SUCCESSFUL, COOPERATIVE NEW YEAR 2009!

There are only a couple of hours left in 2008. I am sitting in the middle of a snow storm in Central Finland, suffering of a flu which I have got as a souvenir from my Latvian visit (Riga is a beautiful city but as cold as Finland during Christmas time).

Looking back to 2008: what has happened on the area of paper industry microbiology?

It seems that certain depression has been obvious in R&D of paper industry - and especially in D. Activities of chemical suppliers will be asked by paper makers to fulfill trouble shooting tasks. Smaller private labs have also been active to assist to solve microbiological problems like H2S production by SRB's, spoilage of raw materials and biofilm formation. 

Novel methods - like PCR and PMEU - are on the threshold of applications. 

I have only one wish for 2009 regarding paper industry microbiology:

I wish that all partners of the joint activities, intended in securing paper process runnability, will have time and interest to build up cooperation. All elements for this are already available:

* experienced personnel of paper mills

* biocide suppliers, having response to help in mb problems

* novel, rapid analytical tools for P&P microbiology

* private, active research institutes

I therefore wish every one 

SUCCESSFUL, COOPERATIVE NEW YEAR 2009!

and promise to myself to be more active as a blog writer for Paper Industry Microbiology!

How much do we understand?

As a microbiologist, IM knows that he can never understand microbial activities comprehensively. This is also known by all his fellows in the field of microbiology. 

How to predict the future steps of a microbial population? What are those factors which are important just on this very moment? Do we actually know them?

As an example: Ca2+ is needed for certain bacteria to produce spores. We still cannot, however, predict the sites of sporulation inside the paper machines because other essential triggers for sporulation may not be known by us.

This does not mean that we must rise our hands and thrust only on the old manners (like machine washings and boil-outs, set in annual calendars on the walls of control rooms). IM does not mean that tradition isn't important - in opposite! - but he would still like to have an optimistic view into the future of rapid microbiological process control. Novel ideas like Quality Control tool "HACCP", microbial activity estimations with "ON LINE ATP" and "PMEU" seem to be more and more well-known in P&P industry today.

Specialists and experts of technical issues begin also to understand the basic fact that it is basically impossible to understand all activities of microbial populations totally because the very complicated interactions of living and non-living components of the systems (which is definitely one of the facts in life which we must tolerate). But our "best guesses" can - and must - be derived from our basic knowledge of microbial metabolism, microbial ecology etc. When this expertise will be connected to laboratory and field experiments and experiences of paper process microbiology, the progress in the development towards better microbiological control of paper machine is secured.

- These ideas of paper industry microbiology seem to be very similar with those which must be understood and accepted in global economy today. No one really know what will happen to the infrastructure of the very complicated network of modern capitalism! Just to have ther very best tools for forecasts and planning!  

Better housekeeping for paper machines.

There has been definitely some improvement in the microbiological control of paper machines since late 1970's (when IM started his work for it). As a very short review, two issues have been highlighted because their positive effect on the hygiene and driveability of machines: application of oxidative agents as biocides and biofilm research. Rapid killing of microbes in strategic sites of processes with compounds like peracetic acid, chlorine dioxide and ozone have given very promising results when the overall load of microbes inside machines shall be dropped. Better understanding of the features of biofilms - essential changes of bacterial metabolism when they attach on surfaces from flowing water and start to release more and more living cells and spores back to the process  - also help to focus attention on them.

Poor interests to invest in better analytical control of microbial activities, in opposite, is surprising, however. Why do the mills not benefit the obvious progress of such control methods like ON LINE luminometry, rapid PMEU incubations etc.? Is it a question of lacking knowledge, lacking interest or the status of old-fashioned analytical methods, not suited to rapid QC/HACCP of paper and board processes? Is microbiology regarded as the unknown living creature on the surface of "Solaris" in the novel of S.Lem (the most excellent film by Andrei Tarkovsky recommended!)

IM has been relatively frustrated for this situation but tries to think optimistic: some small-scale simulations are already running today, and more and more people with technical background have been interested to know about tools to estimate and forecast microbiological events inside their machines. Happy to hear that they understand that with costs of only a couple machine rolls they could have improved microbiological control which can lead to remarkable spare of money when preventing unexpected machine stops or claims of poor product quality by customers.  

The new beginning of P&P industry in Africa?

IM follows frequently the bright blog written by Jim Thompson (http://www.nipimpressions.com/).

His last post discusses about the dark future of Finnish P&P. In opposite, he gives an optimistic forecast: the promising region for the manufacture of pulp and paper could be Africa! After reading his points of view - short but comprehensive - I must agree. Everything could begin once more on this huge continent if only social and political confusions can be won there.

Sitting and thinking - what else? What about a new way to construct paper and board machines? To take into account not only technical issues, but also all chances to have machines which were easier to control and keep clean/safe than these old ones, we are still driving?

There are a lot of relatively simple solutions which can improve the hygiene of raw materials as well as keep wet end area, white water circulation, pulp towers and broke systems cleaner. These ideas were discussed during the professional career of IM and very many wise men (and women) agreed. It has been the question of reconstruction costs which has prevented the realisation of the progress in paper machine development towards cleaner production and processes.

But: what about starting everything once more? To build up machines with clever ON LINE process control and alarm systems? Machines which were easier to clean during production? Machines which even have self-cleaning constructions?

Ozzy Osbourne sings: " I'm a Dreamer" - but what we are lacking just now are the dreams, aren't we?  

Where are the novel ideas?

Where are the novel ideas?

This is actually not my question tonigth. Just to start.. 

There are a lot of them! But are they received?

I will understand it very clearly. My wife is working for young people as a "grand  lady" in Jyväskylä "School Nursery", Central Finland, today (in English: what to do with over 700 youngsters?).

She also has got novel ideas.

But what is the "Black Hole" where all our activities - yours and ours - will be drown?

Novel ideas will promote paper industry to be more economical. 

Where are yours and mine?

On the Threshold of a Dream: Application of rapid mb methods in paper industry

It seems that certain interest in novel, both rapid OFF LINE and automatized ON LINE  methods for the control of paper machine microbiology has arisen at least in Finland. The benefits of fast activities against spoilage of raw materials, biofilm and slime problems in processes as well as immediate corrections of biocide problems is understood in many mills.

What has prevent the progress of microbiological control in the mills until now?

First of all: lack of knowledge (ref. the picture above, drawn by my son in his early years). Bacteria, moulds and yeasts are something frightening for the majority of paper mill personnel. This opinion is false: learning basic facts of microbial ecology, environmental ecology and biotechnology helps to understand the activities of microbes. This kind of knowledge is served every year on trainig courses, intended in to present microbiology to laymen of paper industry.

Another claim: " We shall wash our machines several times per year - we then clean both chemical and microbiological problems away". False again: microbiological problems very often hide inside the process and lead frequently to acute problems which force to stop the production and clean the machine - and in worsest cases, lead to severe faults of products. 

We do not think that visiting our doctor a couple of times per year covers us against infectious diseases all the year, do we? Absolutely not - why then we thrust that infrequent boil-outs could prevent our machines against their "diseases"?

"Where we can catch information of novel control methods? We are not microbiologists?"

A good supply of paper industry microbiology is available nowadays, not only in scientific journals (J.Appl.Environ.Microbiology and J.IndMicrobiol.Biotech.  may be the best sources of P&P microbiology today),  but also on courses, blogs (like this and www.biotechtouch.blogspot.com) and elsewhere in Internet.

Focusing certain activity to be familiar with P&P microbiology isn't too hard task for those persons who are responsible for the technical and quality issues of paper and board production. It is definitely worth to do and to reserve time for it.

Back to the title of this post: great british rock group "The Moody Blues" published and album with the same title years ago. Progressive rock with jazz features (near to the heart of IM) then grew to a respective form of music all over the world on 1960's-1970's. I hope that we are now similarly stepping into a new era of control methods for paper industry microbiology today.

How to present novel mb methods to paper industry?

Novel methods of microbiology have been a most interesting topic for IM for decades. Beginning from 1970's, the value of ATPAssay and RR Test have been obvious, and both were adopted to paper industry on 1980's-1990's.

The increase of economical problems in paper industry are also very obvious today. IM has red articles and blogs about the reasons for this situation in this small, northern country with extensive forests: is it the problem of wood supply (= high Russian taxes for export and decreased activity by Finns themselves to sell their wood to the mills), the overcapacity of fine paper (other P&P products have no problems?) or both?

Back to the subject of my blog (after a short political survey, in which IM really has no expertice):

Paper companies are calling for tools to improve driveability of the machines, to catch better process control systems andto have lower number of product disqualification. Microbiological problems are still huge among all types of paper and board production, and QC methods like ON LINE ATP, BIOTOUCH Concept etc. could help significantly to lower the number of annual hours and days when the machines are stopped because microbiological problems.

But: how can we microbiologist publish these ideas? It seems that people, working for P&P industry, are more and more busy. How can we create a channel to deliver information about new methods to them?

Web-based marketing seems to be one challenging alternative to traditional paper articles, fairs etc. KK-Net (as an example) is doing a pioneer work to activate contacts between P&P industry and research institutes. This can be the way in future what we should follow. 

One must remember: Microbes are active day and night, no matter we may not are!

Petroleum vs. paper industry microbiology - an exciting analogy.

IM has noticed an most interesting review by Lewis R. Brown in SIM News September/October 2007 (SIM = Society of Industrial Microbiology). The author presents us various topics of petroleum microbiology which can significantly help this industrial branch to locate new deposits, to increase production rates, to eliminate corrosion caused by H2S and to have new tools for the bioremediation of oil spills.

What especially has waken IM up was the obvious analogy between petroleum and paper industry microbiology: similar reasons have caused a lag period of the benefication of microbiology. Here are some lines from the beginning of this review article:

" It must be remembered that it was not until the 1940's that a U.S. oil company hired a full-time microbiologist, thus most of the research on petroleum microbiology was conducted in university laboratories. Consequently, potential uses of microbes in the industry were based on laboratory experiments, not field demonstrations, and were viewed with certain amount of scepticism. Also, it must be remembered that microbiology as a science was less than a hundred years old at that time and therefore people in other disciplines, e.g., geology and petroleum engineering, had little or no understanding of microbiology...".

Sounds very familiar to a microbiologist, working for  paper industry. A lot should to be done to publish the multitude of  issues of microbiology which could help paper industry to minimize microbiological problems, to secure product quality and to have benefits served by biotechnological products like enzymes in the manufacture of pulps, papers and boards. 

An ideal biocide - is there any?

What should an ideal biocide be like?

* effective against a variety of microbial species
* effective in different process environments (temperature, pH, RO potential, solid concentrations etc.)
* both fast and conserving type of action
* not harmful for employers of paper machine
* not harmful for paper machine
* not harmful for products of the paper machine
* not harmful for environment
* (something else?)

As far as IM knows, no such ideal biocide has been developed yet. "Tailored" biocide products shall therefore be combined to fight against raw material contamination, microbial activity in large process water and pulp systems, fiofilm producers...

The rapid development of fast-acting oxidative agents (chlorine-and bromine-based compounds, PAA, ClO2 and even O3) is very promising, but they have relatively limited success as storing agents. Their broad-spectrum influence on even bacterial spores should be taken into account
when planning biocide programs, which also should contain compounds to prevent biodegradation during storage periods and formation of biofilms on wet surfaces of the machine.

In some cases, activity of alternative biocides against certain hazardous bacteria are also worth to evaluate.

Shared responsibility for paper machine hygiene.

Current situation of process hygiene control in paper industry is relatively complicated.

No matter very effective control methods are already available (epifluorescence microscopy, ATP Assay, PCR, PMEU incubations) the roles of paper mills, biocide suppliers and raw material producers are not very clear.

Based on the experiences by Industrial Microbiologist since beginning of 80', it seems that paper mills prefer external services and this tendency is evergrowing today. Biocide suppliers have developed novel analyse methods which can be applied even at the mills, and many raw material suppliers know their response to deliver minerals, starches etc. with good hygienic quality for paper and board mills.

What should still be developed is the active role of paper mills themselves to control their machines. There is no more any need for expensive microbiological laboratories - in opposite, many methods could either be applied by wet end laboratories of the mills or be bought from external companies (ref. BIOTOUCH Service).

Wet end chemistry has already been controlled with ON LINE analyse units by certain institutes in Finland over years. ON LINE microbiological control is also coming soon, referring several current project proposals.

A combination of all parties - paper mills, biocide suppliers and raw material producers - would spare remarkable amount of money by optimizing biocide programs, by planning washing programs, by responsing immediately to hazardous situations and avoiding costs of returned products.

Evaluation of slimicides for paper machine process waters.

Time series of steel coupons are the common method to evaluate the effects of biocides against slime-forming bacteria in paper machine processes.The installation of coupons inside the machine may not be the main problem. Two other aspects will limit the value of this method:

* only one slimicide (= the current slimicide used in the machine) can be tested
* duration of the evaluation may take days...weeks

PMEU Incubator (by FINNOFLAG Oy) has been adopted into biocide and slimicide testing because it gives chance to

* evaluate several biocides/slimicides at the same time
* only hours to days are needed to have the results of evaluations

Picture (above) shows a bacterial population, attached on the surface of a PMEU test coupon, with fibres, minerals and starches. These bacteria stand washing of coupon with water after testing which means that they are "primary attachers" on the surface of steel when immersed in process water of a paper machine.

How to control the microbiological status of activated sludge?

There is one area of paper industry microbiology where active measures are needed to cultivate microbial flora: biological waste water treatment plants.

When focusing on activated sludge of aeration basin (anaerobic treatments will be discussed in another post), the roles of different microbes should first be understood.

The tasks of bacteria and protozoa - which are the beneficial microbial groups in the purification process - are different: bacteries are responsible for the transformations (mineralisation) of incoming organic compounds, Protozoa collects small particles (also bacteria) and acts as indicators of the activated sludge condition.

Bacteria shall also build up "flocs" which can settle down and be either returned backwards into the beginning of the purification process or totally removed from the plant. Significant amounts of nutrients will also be lead to the "sludge route" which is especially important for environmental reasons: no matter relatively low concentrations of nitrogen and phosphorus (compared with municipal waste water effluents), the volumes of P&P waste water effluents are huge.

Traditional parameters which are related to the microbiological status of activated sludge are C:P:R ratio, temperature, pH and oxygen concentration. In addition, the share of Protozoan indicator organisms are checked by microscopical methods.

ATP Assay is also a fast and reliable method to check the viability of activated sludge and control unfavourable sludge escape from secondary sedimentation basins (IM has written his second graduate work about this issue on 90's).

Incubations with PMEU equipment (FINNOFLAG Oy, Finland) have been very successful when the effects of low oxygen concentrations on the structure of flocs are the subject of the study. This method, in connection of bright field/dark field/phase contrast microscopy, gives also fast responses (even in hours) when the detrimental effects of toxic water fractions on activated sludge flora shall be checked.

There are many reasons for the bulking of activated sludge: nutrient supply, oxygen concentration, temperature etc. In all cases, a layer of activated sludge will rise on the surface of the basin and cannot be taken away from the water flow to sedimentation stages.

Measurements of redox potentials can give more information about the risks of anaerobic growth in biological waste water purification systems than sole oxygen concentration analyses(practical reslusts by IM). RO potential control may also work as a replacement/addition to traditional Respiratory Rate test, often used to check the viability of activated sludge.

Microbial activities continue also in sedimentation basins. IM has detected a significant rise of nitrogen concentration in certain basins in studies performed on 80's. The reason is obviously the activity of a coliform species, Klebsiella pneumoniae, which is able to fix nitrogen from atmosphere (nitrogen fixation). The routes of the pathogenic Legionella pneumophila in the purification process should also be investigated more deeply. Novel types of analytical methods to replace the traditional colony count methods (intended in the control of household water) shall be developed, however: L.pneumophila is very hard to "find" among other bacteria and fungi which are capable to grow extensively on selective nutrient media for Legionella.

ON LINE control has - until now - not got any role in HACCP of waste water treatment systems but promising technical solutions are already available for semi-continuous control of activated sludge microbiology.

Biofuels from pulp industry have a gret potential in future.

IM follows frequently the network site "The Paper Index Times" which has published this new post today:

"Monday, July 14, 2008

Paper and Pulp Mills Poised to Produce Biofuels
No other industry is so well suited to produce fuels from waste wood cellulose than the paper/pulp industry. By converting pulp by-products from waste to precious fuel, pulp mills can do a big favour to themselves, the environment, and the energy consuming public.
The pulp and paper industry has the scale to produce more than 9 billion gallons per year of biofuels, or as much as 20,000 MW of biomass power - as much as 16 Quads of cumulative fossil energy savings – realize net CO2 emissions reductions of more than 100 million tons annually, in the process generating financial returns, relative to continued investment in existing technology, with internal rates of return between 15-40% depending of fuel prices and incentives, according to a presentation given by Navigant Consulting’s Ryan Katofsky at the “Florida Farm to Fuel Summit,” which took place in St. Petersburg July last year....Gasifying rather than incinerating black liquor in soda furnaces – as is common practice - results in the production of a number of by-products, including synthesis gas. The bio-syngas can then be turned into a range of liquid fuels, such as methanol, dimethyl ester (DME), Fischer-Tropsch synthetic diesel and hydrogen gas. _SourcePulp mills could easily become energy self-sufficient by using the waste process heat of paper manufacture, and eventually supply energy to the outside in the form of electricity or fuels. The more productive uses that can be found for solid waste, waste sludge, waste exhaust gases, waste heat, and waste water, the cleaner the environment will become--land, air, and water.
Labels: cellulosic fuels, garbage energy

Features of sporeforming bacteria.

Sporeformers are certain bacteria which can transform themselves from vegetative (= growing) form to spores (= resting form). Best-known examples of these bacteria are aerobic sporeformers ("bacillus-type", inc. Bacillus sp. , Paenibacillus sp. and other Gram-positive, aerobic sporeformers) and anaerobic sporeformers (most common species belong to the genus Clostridium). These bacteria are very common in all environments, especially in soils.

Spores of bacteria are not intended in the reproduction of organisms (like fungal spores) but to keep bacteria alive in conditions where they cannot be metabolically active. Sporulation is caused by the lack of nutrients, and germination of spores takes place whenever environmental conditions turn better for the growth of the bacterial cells.

These bacteria are a problem for paper industry because their spores tolerate dryness, cleaning agents and biocides very well. Their main sources are mineral pigments and starches, especially when these raw materials are delivered to the mills as dry powders. Whenever they are slurried, an effective biocide program shall be applied in the total system of their storage and dosing into the machines.

Another problems are analytical ones. Spores can be detected after a simple pasteurization of the samples (vegetative cells get killed, only spores stay alive) but this procedure kills also vegetative sporeformes. An analysis called "Sporeforming bacteria" does therefore not show potential sporeformers which are in vegetative growth phase. In addition, germination of spores, like every other chances in the properties of bacteria, takes certain time. This slows the growth of spores on nutrient media significantly. Fastest germination times can be achieved by PMEU incubator but the outgrowth of spores into vegetative cells may take much longer periods on the agar plates.

Evaluation of biocides should also be done with equipments like PMEU which show the different effects of biocides in the original samples.

Last but not least: if the growth of certain aerobic sporeformers has been very active, starch-degrading enzymes can stay active after biocidic treatments. Amylases can be found even after heat treatments because many of them are thermotolerant ones.

Sporeforming bacteria of paper industry have been studied very actively in Helsinki University, Dep. of Applied Chemistry and Microbiology. IM recommends to read scientific articles, written by the research group of Professor Mirja Salkinoja-Salonen, in magazines like "Applied and Environmental Microbiology" and "Industrial Microbiology and Biotechnology".

This group of bacteria is always a target of HACCP activities of paper mills, especially when products with high hygiene quality are manufactured. Studies to understand their features is therefore continuing also in future.

Concepts of microbial ecology and biotechnology in process industry.

Coming back to the issues of microbial ecology and biotechnology:

Both of them have helped IM to understand the multitude of microbial activities which are typical for paper industry. Technical framework, beginning from the preparation of raw materials and ending to the waste water treatment plants can be regarded as fermentors or bioreactors where growth conditions vary a lot. Everlasting input of bacteria (and sometimes also fungal organisms) contain strains which can be adapted into these processes and live in them over very long periods - even tens of years. These topics, definitely, belong also to the research area of microbial ecology and its theories about adaptation, competition, synergisms...

These issues have been discussed by IM already in previous posts and shall be taken into account - in more detailled form - in near future.

By the way - what would be more interesting than to have shared net forum of paper industry engineers, environmental microbiologists, ecologists, biotechnicians and other specialists to discuss about similarities and analogies between natural environments and paper mills? Even limnology gives hints to understand certain microbial activities - like the growth of microbes in water flows as biofilm organisms. Another analogy can be found when observing the microbial populations of lake or ocean sediments and the microbial flora of different kind of depositions in paper mill machinery.

IM is looking forward to hear various multiscience views by biologists, biotechnical and environmental microbiologists, ecologists, limnologists and oceanologists about similarities between natural environments and paper machines!

Why shall paper industry be moved to foreign countries from Finland?

IM was sitting with an old friend from Helsinki on the terrace of his summer cottage (no water lines, no electricity)on yesterday evening.

- (IM) Where are we going in near future?
- Basic production (agriculture, fishing etc.) will be respected after a while...
- Why we cannot continue P&P production in Finland?
- Labour costs are not the problem. Their share is under 10% of the costs of paper production.
- But..?
- Transport of the products and price of the raw material are the main problems.

IM has read from local newspaper "KESKISUOMALAINEN" about the problems of timber production. A manager of timber enterprise told that "the taxes are the problem. Price of the Finnish raw wood is too high today. Government should help to have wood with acceptable prices..".

This is economy.

Microbiology shall be taken as an important issue in paper production.

IM will thank Dr. Elias Hakalehto about his valuable comments!

It seems that there is only one industrial environment where the intense growth of harmful bacteria is allowed: paper and board production.

This is caused by the need of huge amounts of water inside paper mills. This water is carrying valuable raw materials and (despite the frequent questions by IM) the most spoiled water fractions will not be delivered to waste water treatment. The spare of water has led to (microbiologically) insane solutions like the use of certain white water fractions in spray water system of wire section. Every microbiologist knows what happens...

There are several microbiological threats in paper industry:

* spoilage of raw materials
* biofilm and slime problems of the machines
* defects of product hygiene
* health risks

Production of paper without water was discussed at 80's. It does not work. Connection of fibres in wire section has failed. Water is needed to form a network of fibres, strong enough to "jump" to pressing section. It is an impressive event: still having tens of percents water, paper will go independently over a gap between wire and pressing rolls, without any support...

Water is needed in paper machines, no doubt. But how to control its microbiological quality?

Harmful bacteria can (which IM has experienced) be detected with rapid methods like PMEU, ATP Assay and PCR. It is the question of (economical) resources if it will be done.

The role of Klebsiella pneumoniae as an opportunistic pathogen in paper industry.

Klebsiella pneumoniae is a common bacterium of the BERGEY's group "Gram-negative facultatively anaerobic rods", having motility by peritrichous flagella and being unable to perform oxidase test positively.

The former description indicates that we can set K.pneumoniae into the family Enterobacteriaceae with such, maybe better-known bacteria like Escherichia coli and Salmonella sp. They all have one distinct feature: they can grow either aerobically (= in an atmosphere containing oxygen) or anaerobically (= in an atmosphere without oxygen). The presence of two different energy metabolism, aerobic respiration and fermentation, allow this adaptation into two significantly different environments.

Klebsiella pneumoniae likes to live in wet environments and can use different sugars as the source of energy and carbon.

All these features of this bacterium declare its tendency to live in paper industry waters containing sugars from wood (waters originating mechanical pulp production; debarker waters; waste waters containing pulp mill effluents). The capability to use atmospheric nitrogen (N2) as the source of nitrogen (called nitrogen fixation) is also common among K.pneumoniae strains and gives to it good chances to compete with such microbes which are depending on organic nitrogen supply - which is often very poor in paper industry waters, having low N:C ratio.

What makes this peaceful situation more hazardous, are some other features of Klebsiella pneumoniae: its ability to produce exopolysaccharide capsel (= slime) and its resistance against several antibiotics. Optimal temperature for its growth is 35-37 oC which is responding to the body temperature of a man.

It has been described as an independent species already in 1885. Genus is named respecting famous Dr. Klebs, well-known microbiologist; name of this species comes from its ability to cause bacterial pneumoniae and other severe infections which may be fatal for weak persons (very young, very old or those having poor immune response like cancer patients). BROCK says: " ..the presence of bacteria in the blood is generally indicative of systemic infection. The most common pathogens found in blood include...enteric bacteria, especially Escherichia coli and Klebsiella pneumoniae...".

The physiological and biochemical features of K.pneumoniae strains isolated from patient samples and either from waste waters (DUFOUR & CABELLI 1976) or from paper industry processes (MENTU 1982) are very identical and the risk to be infected by this opportunistic pathogen is therefore obvious.

Finnish Work Environment Fund funded a research project in the beginning of 80's to investigate health risks, connected to the contaminated aerosols in the paper machine and debarker halls. K.pneumoniae was one of the microbes investigated in this research. The results of this extended project were published in Appl. Environ.Microbiology (SEPPO I. NIEMELÄ, PENTTI VÄÄTÄNEN, JUHA MENTU, ANTTI JOKINEN, PAAVO JÄPPINEN & PAAVO SILLANPÄÄ 1985). The writers said at the end of this article's Discussion: "...The lack of correlation between microbial incidence and occurrence of symptoms seems to indicate that permanent colonization of the process water microbes is not common or that the human pathogenity of these microbes is low. The microbes found in nasal cavities were evidently mostly transient. We conclude that the natural host defenses of the basically healthy adult worker population are normally effective enough to protect the workers from the the opportunistic pathogens present in the process waters and in the air of the paper mill environment. This does not preclude the possibility of a worker's becoming a host to a pathogenic microbe when the worker is in a subnormal state of health".

After 20 year from the publishing of this article, first cases of Legionella pneumophila infections, connected with paper industry, were found.

- Detailed list of references is not included in this article (to spare rows) but available on request from IM.

Pathogenic microbes in paper industry?

A paper industry professional (graduated in technical, not in any biological department) discussing with IM. - Every sentence in this story is fictional one (like they tend to tell at the end of many movies) but they base on those years (nearly 30), during which IM has been involved in P&P microbiology and they, in a way, are a condensate of frequent discussions about microbiological topics on the meetings and in the paper mills:

- You have told us that there may be over million living bacteria in every milliliter of white water inside a paper machine?
- Yes. High number of scientific reports by independent researchers can confirm it.
- What about viruses?
- Obviously there are viruses - but not those which are pathogenic to man. Viruses of paper industry will infect bacteria, they are called bacteriophages.
- What is the reason for the fact, there are no viral human pathogens?
- No significant source of those viruses - you can find them in waste waters of villages and big cities but, as you understand, people tend not to release their viruses into paper machine processes...and...
- And...?
- If there were viruses, pathogenic to man, they should have host cells...
- Wait a minute...bacterophages infect bacteria...
- You got it! And human viruses need human cells as hosts - they cannot reproduce themselves outside their host cells.
- Genetics..I know. And specified viruses to infect specified cells...
- Yes. They shall, in a way, "match" together.

A moment of silence. Fish are jumping on the lake, western horizon turns from yellow to darker shades.

- What about bacteria? If there really are so many there?
- That is a much longer story. We will discuss about hazards, caused by the bacteria, tomorrow morning.
- O.K. It is a late evening, sun has just gone down and..
- ...and the best time of the day for fishing!

(continues...)

Automatized control systems for paper industry microbiology are coming.

IM read good news from international, net-based paper industry newsletter: oxidative agents can be measure automatically today!

Next step is obviously automatic measurement of microbial activity. A couple of analytical methods are available for this purpose. Forecast by IM is that some of them are in practical use already before the end of this decade.

This kind of automatized control needs rapid methods (like PMEU incubations and combined analytical methods to achieve fast results) for frequent evaluation of biocide alternatives, solving of trouble shooting situations and detection of harmful microbes (Bacillus cereus, Deinococcus geothermalis, Klebsiella and Burkholderia species, Sphaerotilus natans, Legionella pneumophila, amylolytic and cellulolytic microbes etc.).

Now it is the right time to start rapid control methods of paper and board machines. Colony count analyses take too much time to be a real HACCP alternative, and they are very laborous.

- Net newsletter tells:

"NAPERVILLE, Ill., USA --June 23, 2008-- After successful trials that created improved product quality, operating cost savings and environmental and safety performance benefits for papermakers, Nalco Company (NYSE:NLC) has launched OxiPRO(tm) Deposit Control technology to the global pulp and paper industry. This novel, patent-pending control technology combines measurement, data analysis and precise dosing with proprietary chemistry to prevent unnecessary downtime and product defects. Real-time measurement of changing surface deposition, microbial activity and process conditions triggers proprietary data analysis software and on-site application experts to ensure that feed points, dosing strategies and the proper proprietary chemistries continuously optimize papermaking performance. "This new technology offers invaluable benefits to our customers - targeted to their unique application requirements - by controlling costly variability in microbial growth and surface deposits. Real-time control allows Nalco to help customers reduce operating costs and use chemistry only as needed, which reduces safety hazards and the potential for upsets to the health of the wastewater treatment plant," said Michael Meier, Nalco's Global Program Manager for Deposit Control Expertise Center. For more information about Nalco's innovative OxiPRO Deposit Control Technology, visit www.nalco.com/OxiPRO, send your inquiry to oxipro@nalco.com or contact your local Nalco Sales Engineer. About Nalco Nalco is the world's leading water treatment and process improvement company, delivering significant environmental, social and economic performance benefits to our customers. We help our customers reduce energy, water and other natural resource consumption, enhance air quality, minimize environmental releases and improve productivity and end products while boosting the bottom line. Together our comprehensive solutions contribute to the sustainable development of customer operations. More than 11,500 Nalco employees operate in 130 countries supported by a comprehensive network of manufacturing facilities, sales offices and research centers to serve a broad range of end markets. In 2007, Nalco achieved sales of more than $3.9 billion. For more information visit www.nalco.com. Source: Nalco"

How much is needed to know?

IM is thinking about the various levels of microbiological knowledge, needed to control risk factors of paper and board production.

There is certainly some basic level which shall be reached. Colony counts - both "total count" and counts of more specified microbial groups - serve as the first steps and can very often tell much about current HACCP status to the operators of the machines.

Another basic activity - especially in trouble shooting situations - is microscopy (which has been discussed earlier on this blog). It also gives one view into microbiology of the processes and can also been applied to trouble shooting of product problems whenever challenges of epifluorescence microscopy are available.

Colony counts, of course, tell us about the microbes which are the members of ecosystem / bioreactor called paper machine (also discussed earlier...). Still there are (at least) two points of view which are missing:

• what kind of environments are favoured by the microbial populations? Temperature, pH, redox potential, certain chemical compounds, any symbiotic relationships, any antagonistic effects, tendency to grow in water / on the surfaces....?
• what are the main activities of the microbial population? Growth rates? Age of the population (LAG/LOG/KILL)? Special metabolic activities (enzymatic breakdown of starches by amylolytic bacteria etc.)?

It is questionable if any identifications of microbial flora is needed in all cases but, whenever done, ID information tells us, what the microbes are able to do (no matter, they really do not always act like "they should" when referring literature!).

It is the combination of two features - count and activity - of microbial flora which matters. Colony counts alone really do not tell everything about the activities of the flora. Some specified tests - not necessarily very complicated - can be done to understand the main metabolic activities which are going on in the process. One example may be HUGH&LEIFSON tests, teached on all primary microbiology courses of universities, which very easily give information of energy metabolism, favorite carbohydrates, motility and gas formation of isolated bacterial strains.

RAPID METHODS can also tell about the combined effects of count and activity of process flora. PMEU incubator by FINNOFLAG Oy is very much recommended to assays where certain metabolic activities shall be evaluated (see also www.biotouch.blogspot.com). Enzymatic attack by microbes against different additives can be checked very fast in this way.

A combination of some basic tests for the main representative isolates among total count analyses - basic microscopy, Gram test, oxidase ad catalase tests, HUGH&LEIFSON tests etc. - give valuable information about the main features of total population but this data works as a tool for QC and HACCP only when combined with the experimental results of activity tests and knowledge about sensitivities to different types of biocidic treatments.

Microbial ecology shall still be mentioned as the solid basement for the understanding of potential activities which microbial flora of paper and board machines and their raw material lines is expected to perform. Ecological way of thinking can also tell how the situations may change in near future if one or several basic growth factors are altered.

Future forecasts (like "weather report for a paper machine"- an analogy presented by Helge Keitel, one partner of BIOTOUCH group) should therefore be based on both fast and reliable investigations of process activities and on the overall knowledge of microbial ecology.

As a conclusion, the main task is therefore to answer to the question:

What can happen under certain environmental conditions when certain microbial activities have been detected?

Paper mills, model 1908 and 2008?

To produce paper, lot of activities besides technical operation are needed.

IM tries to review a paper mill in 1908 (no matter has not born so early...). Machines have bougth from foreign countries (from U.S.A., maybe?), products have been chosen (obviously there were no very many brands on a single paper machine) and fibers were derived mechanically. Water consumption was high (because no environmental pressures at those times). Lots of people working in non-automatized jobs. Markets were both local and international, but relatively easy to understand.

All has changed significantly in one hundred years.

New products; new processes; new raw materials; diversity of grammages and brands on one machine; international, complicated markets...

Two issues have got overwhelming importance: speed and R&D.

These two are interconnected. A machine without careful R&D already in the construction of pulp, raw material and process systems cannot work very well. R&D is also needed in trouble shooting situations (the price of your lunch may be lower than the cost of one delayed production second of the machine).

What are then the roles of R and D today?

The needs for QC are ever growing: faster analyses to avoid economical losses. Paper mill laboratories work to fulfil this task. R is certainly needed to improve the methods of QC.

D should be connected to R to produce new methods for these analytical and operational tasks - not only to develope new kind of products, which also is very important). The personal opinion of IM is that the gaps between R and D are usually caused by economical reasons: everybody respect R but the connection from research results to improved methods may be long (and long-lasting).

Curiosity and interest in the development of new methods is still worth of all expences. More secure driving of machines, more stable quality, less trouble shooting...

What is needed to produce good paper?

IM is sitting on the terrace of his summer cottage. Sun is still high in southwest, seagulls are screaming -everything so peaceful.

And then the idea: what is needed to produce good paper?

First, people.

Those people who are interested in to drive a paper mill. All issues included - and there are many of them.

Price of wood; transportation of wood and other raw materials; services for the paper machines; 24 h driving of it....

In the beginning of his career, IM tend to visit control rooms of a paper machine during evening time. Sitting there, watching all the controls of the monitors, discussing about problems and how to cure them.

For some reason, microbiology has always been an interesting topic for personnel of a paper machine. What can happen to the raw materials? Can microbial activities cause problems in broke systems? How shall the water circulation and tanks be handled?

IM feels very humble today - to be one link in the complicated process called paper production.

One link - but as important as other links as well.

To understand the very multiscientific field of paper production - not to forget all activities to keep it on an economical satisfied level - is a hard task. What is needed (thinks IM) is to understand each other's work. It takes time to understand this truth - not your area only, but all efforts of others are needed to produce Good Paper.

ON LINE methods for paper industry microbiology.

Rapid and ON LINE methods of microbiology have gathered evergrowing interest in pulp and paper industry.

There are several features of these novel, alternative control tools which will give significant benefit when raw materials, processes and products are the subjects of microbiological QC:

• specified physical, chemical and biochemical analyses can be arranged to give fast and reliable information about the amounts and activities of microbial populations
• analytical results can be collected and processed to give time series with frequent observations
• main statistical tests (like correlation and regression analyses) can also be performed to show any dependences of microbiological status in critical points of the processes as well as the response of microbial flora on major growth factors in "paper mill ecosystem"
• Real HACCP needs rapid analyses and fast reporting from CCP sites
• Statistical testing can be based on Normal Distribution of obsevations (compared to Poisson Distribution when colony count methods or microscopy is applied)

IM has noticed very promising progress in co-operation between paper industry research and developers of rapid analytical tools during last years. Maybe a real HACCP can be constructed in pulp and paper industry in near future?

Global distribution of paper industry microbiology.

IM felt very happy to get a message about the honour to have his blog connected into a global net news organisation for paper industry:

"We have a popular pulp and paper industry news website (http://news.paperindex.com) where we have started covering blogs too. We have posted headline and snippets of your latest blog post on our website. Hope this will help you generate good traffic to your blog."

Microbiology is connected to paper industry in many ways which have been discussed in this blog. There are also microbiologist working on this area worldwide - their number may not be high but their work is very valuable for the use of P&P raw materials, running of the machines, performing QC of paper products as well for the biological waste water treatment.

"Density of paper industry microbiologists" is definitely low in the world but IM hopes that blogging will increase its popularity among P&P microbiologists and he tries himself to inform all readers of www.industrymicrobiologist@blogspot.com about new ideas on this area. He also recommends to visit www.biotouch@blogspot.com which also contains recent news and future forecasts of microbiology and biotechnology.

Microscopy as an analytical tool for paper industry.

IM (Industrial Microbiologist) has worked as a microscopy teacher and trainer for paper industry since the beginning of 80's. It seems that this analytical tool is very popular: annual courses in Helsinki and at the customers' facilities have indicated an everlasting need to achieve training and experience in microscopy.

There are three major areas of paper industry where microscopy can serve as a rapid tool for analytical control:

• Raw material, process and product microbiology. Traditional Bright Field, Dark Field and Phase Contrast microscopy are always valuable methods. Epifluorescence microscopy techniques (Confocal microscopy included) help significantly when biofilm studies with test coupons will be performed.
• Fibre microscopy. Bright Field microscopy of stained fibre preparates is a common method for the investigations of fibre contents of paper and board.
• Activated sludge microscopy. This is the fastest and most reliable method to check the main activated sludge properties: condition of microbial population and flock formation. It also gives information about sludge age.

Technical equipment for paper industry microscopy bases on ordinary light microscopy, but some prerequisites are needed when microbes are the subject of study:

• illumination technique for "wet preparates" = Phase Contrast illumination.
• higher numerical aperture than for other applications to reach distiction of small objects (an example: N.A. > 1.0 for 40x Phase Contrast objective which means the need of oil immersion - type objectives).
• Epifluorescence (UV) illumination (for trouble shooting and test coupon analyses).
• high-sensitive digital camera (to detect objects in Epifluorescence microscopy).

Laboratory technicians, operators and researchers of paper industry are very interested to apply microscopy into their analytical procedure. These methods, however, need time and patience when learning to explain the views on the preparates. Training is first needed to diagnose all the raw materials of the processes, typical paper industry microbes etc. before a microscopist is ready to solve real trouble shooting samples. The knowledge of different type bacteria, protozoa and higher organisms of activated sludge systems is also needed.

There are two ways to collect experience for the evaluation of microscopical preparates: either training alone with different well-known preparates (tip: slides with bacteria can be bought from certain companies) or join courses where paper industry microscopy will be teach (such kind of courses will be held annually at least in Finland).

To be familiar with a paper machine...

Sun has already risen. Taxi leaves Industry Microbiologist (IM) at the mill gate. Wishes of good morning, a short phone call, registration as a visitor...

Then to the mill office. Friendly welcomed by the hosts - usually both from the production and QC laboratories. "Coffee?" - "Thank you, certainly!".

Short conversation about everyday issues. Everybody is sitting down. The meeting can start.

Short presentation of the company, mill, machines and products (if not already known by IM). It is interesting how informative such presentations today are! Basic facts, not too much - room for detailled questions.

Then towards the topics of the day.

There are several types of problems, caused by the microbial activity in raw materials, processes and products. Every problem is individual one and strictly confidential, but references from other mills are relatively easy to find. No more discussion about the problem itself at the moment, but ideas are stored somewhere in the mind.

Process layouts! Excellent! They are really needed to understand this new machine as "fermentor and ecosystem". What kind of raw materials+ What comes from where? Conditions? Flows? Delays in flows? Storage times? Biocide programs? Washing strategies? Several details...

And every time, after the answers - to store all this information somewhere in the mind (of course also on paper). To be processed later in the hotel room with a a pen and a sheet of paper. Different techniques- statistics, time series, even mind mapping...

But, before departure from the mill: visit to the machine. a most important issues. Analytical results from the control room of the machine, discussions with the personnel...Checking CCP's of the wet end and tank section, broke system...

Even more small details to send somewhere, in the back of the head.

Some analytical procedures before leaving. Rapid methods, if possible: luminometry, PC microscopy...

After overnighting, back to the mill. Person at the gate is alredy known by IM. "Hello, I will call...".

Straight to the meeting room. Some new persons have already arrived. Exchange of visit cards (how many different visit cards are there in the world? Is somewhere a museum for visit cards?).

Short summary of yesterdays' experiences and some proposals to be discussed. New persons present new ideas and new points of views. Conclusions, future forecasts.

Collection of small samples (easy to carrry with in IM's car - or to be packaged in a separate bag when flighting). Then the final meeting: what shall be done next? By who?

Farewell wishes, very friendly. Most important dates for activities, meetings, e-mail contacts have already been confirmed.

Leaving the mill - a satisfied feeling: something will progress, some help has been given...

- A typical visit by Industry Microbiologist in a paper mill. He really likes his job!

"Triangle" joint projects / services of paper industry microbiology.

Paper industry microbiology - both research and services - is suffering from the lack of money today (as other research areas, too). Company R&D prefer joint projects instead of their own institutional research. There seems to be certain synergism between partners of paper industry (paper mills, raw material and biocide suppliers as well as research institutes and independent researchers on this area).

A "triangle model" of a joint project has proven to be beneficial one. Alternatives could be

* paper mill + biocide supplier + microbiological services
* raw material supplier + biocide supplier + microbiological services

National funding is very hard to achieve today: a lot of project proposals will be sent every year but a small fraction of them will be accepted by the funding organisations. Direct contacts between partners (mentioned above) in developmental, control and trouble shooting cases are faster and a combination of paper industry experience, knowledge of biocide chemistry and microbiological skills can give the best results in improvement and development of paper machine process and product hygiene.

What is paper industry microbiology?

A combination of paper industry and microbiology is rare.

The last textbook about this topic was published in U.S.A. - the year was something like 1955 (when I was a small boy).

After that, a lot of things have happened. It is a most interesting issue. Have you heard about

* "ecocatastrophe" in process microbiology during the change from acidic to neutral/alcalic process?
* the role of bacteria in this new situation - all environmental conditions in a paper machine have changed?
* the role of calcium carbonate and kaolin in the microbiology of paper machines?
* ever increasing recirculation of process waters give more growth period for selected process bacteria?
* sporulation of bacteria is stimulated by longer recirculation periods - what does it mean?
* biocides may be dosed in TOO LOW levels - in opposite to opinions that all kind of microbiological control of process water automatically lead to lower consumption of biocides?

These are issues which I have dealed with over 20 years. I am therefore asking your opinions!

Benefits of microbiological process control - in money?

There are several ways to calculate economical benefits of a proper mb control system. Mind-mapping technique can be used first to detect all aspects included:

TOTAL ECONOMY

• ECONOMY OF PRODUCTION
• SAVINGS CONNECTED TO SECURED PRODUCT QUALITY
• OTHER ISSUES...?

ECONOMY OF PRODUCTION

• COST OF SPOILED RAW MATERIALS
• OPTIMAL BIOCIDE PROGRAMS
• MINIMIZED WASHING & BOILOUT PERIODS
• PREVENTION OF DRIVE DELAYS
• OTHER ISSUES...?

SAVINGS CONNECTED TO SECURED PRODUCT QUALITY

• CUSTOMER CLAIMS....
• FLUENT CONVERTING ACTIONS
• IMAGE OF THE PRODUCT BRAND
• OTHER ISSUES...?

An active, problem-preventing microbiological control of raw materials and processes is a most important activity of a paper mill to prevent costs, connected to poor process managements and product faults. We can calculate this value in many ways:

* how much money is spent every second when the production is delayed? 10 euros/s?
* what is the price of a lost jumbo roll, 10...30 metric tons? 5000 € to 30 000 €?
* what are the costs of ineffective / too low / wrongly distributed biocide dosage?
* how much money is spent when a lot of mineral filler or starch is spoiled in a storage tank?
* how much working time of the mill employers is spent for corrective measures after a microbiological problem situation?
* comparison of proper HACCP, based on rapid mb methods and an old-fashioned microbiological control, activated only in hazardous situations?

Different points of view....please think over and refer!

Rapid control of microbiological status of a paper machine.

Paper industry trust on traditional, proven microbiological methods. Customer claims force the paper mills to use them for end-product QC.

Fast detection - and forecasts - of mb problems cannot be performed by these methods. Some promising progress has taken place since 90's, however:

* optical detection of attachements in paper machine water systems (usually based on IR techniques)
* collection & microscopy of test coupons from processes
* luminometric methods for the evaluation of microbial activity in raw materials and processes

Unfortunately there seems to be no "rapid method" for the estimation of product hygiene yet. Methods of molecular biology may help in future?

Luminometric methods, connected with the examionation of real ("ecologic") process samples is the best alternative for specific assays of microbial counts and activities. Combination of rapid incubation and luminometric assays of process samples is available today ("BIOTOUCH" concept, see figure in right marginal below).

Several calculations and estimations about spare of money has been done. All of them indicate significant reduction of costs which are caused by poor-acting biocide programs (ref. inadequate antibiotic treatment of patients!), problems in machine drive and decreased quality of paper and board product.

Joint projects for the development of paper industry microbiology?

For certain reasons (described in the letters below) the methods of paper industry microbiology shall be critically reviewed. Transferring traditional methods of food and clinical microbiology (as the most obvious sources of P&P microbiological methods) may help to prove the hygieny of paper and board products but cannot actually work as "rapid methods" for process control at all.

The need of cooperation between paper industry, microbiological institutions and developers of microbiological methods is obvious. There are several alternatives to build up joint projects for proceeding of microbiological process and product control but, for some reasons, the interests of the potential partners do not meet.

It would be interesting to hear different opinions about the chances to combine R&D activities (and money!) in the area of paper industry microbiology. Be first to comment!

Standard vs. novel methods of microbiology in paper industry?

Standard colony count methods give reliable estimates of the number of cultivable bacteria in paper industry samples.

They also serve as documents of the hygiene of paper industry products.

HACCP of paper and board machines cannot be based on these methods, however, because they do not give immediate information about the process and product hygiene. Active, fast responses to the hazardous changes of microbiological status cannot be guided by colony count methods. Something shall be done at once, in minutes or hours - not after CFU incubation periods of 1...5 days.

Traditional standard methods are still the first choose when observing paper industry microbiology. There are several facts which still prevent the application of "Rapid Methods of Microbiology", already popular on other areas of microbiological process and product control, into paper industry:

* CFU methods have been accepted by the customers for a long time (tens of years) ago
* novel, rapid alternatives of microbiological control are not known by the technically-orientated personnel of paper industry
* interchange of microbiological knowledge between paper industry and other branches of global industry are still few (paper industry research , in a way, is relatively isolated whenever other topics than physicochemical and technical paper research are concerned)
* new methods are very rarely accepted among standard mb methods of paper industry

What must be done to apply "Rapid Methods of Microbiology" into paper industry, where they could act as valuable tools for HACCP of process and product hygiene?

Microscopy as a control tool in paper industry.

A microscope, intended for microbiology, can be very effective tool in the microbiological control of paper machines. There are some technical differences between paper analysis and microbiological analysis microscopes, mainly in their optical features (depth of field as an inverse factor to distinction of small details etc.) but, in most cases, a middle-price, modern paper analysis microscope can be modified for microbiological examinations.

Some illumination methods - not so familiar on other areas of microscopy - are especially beneficial for paper industry microbiology analyses. Dark Field illumination (with special condensor) can help to find tiny (< 1 micrometer) microorganisms, Phase Contrast illumination (needs certain types of condensors and objectives) is excellent when checking living, non-stained preparates and UV Epifluorescence Microscopy opens new chances to differentiate living and non-living microscale objects.

Assaying microbial activities in paper machine processes.

To evaluate the potential of microbial growth in paper industry processes, traditional colony count analyses do not fulfil all needs.

Colony count analyses (cfu/ml or cfu/g) are well-known methods to detect certain microbes or microbial groups. The are valuable when specified troublemakers shall be detected.

Total effects of microbial growth cannot be seen by using only cfu methods because
* they do not show the activities of microbes, only their counts
* they are performed in artificial environment (nutrient media), not in the original samples

Rapid incubation of process samples is needed to show potential hazard, caused by process population. Biocide testing is also better to do in original samples from beginning to the end.

The most promising method to perform these kind of "mini-fermentations" today is PMEU incubation (Portable Microbiological Enrichment Unit; FINNOFLAG Oy; Kuopio, FINLAND) which gives results of microbial activities and effects of biocides in hours (compared with days when cfu methods are applied). No protecting, stimulating, inhibiting or other selecting effects of nutrient media are also totally excluded in process sample incubations.

One of the main ideas of microbiology is: Both the counts and activities of microbes shall be taken into account. Populations with relatively high colony counts can have slow metabolic activity - and in opposite.

As a summary: microbial activity, not the count of colonies, causes problems in paper industry processes.

Mineral pigments and fillers as a hazard to the paper production hygiene?

"Microbial contaminants will decrease the quality of pigments and fillers in paper and board industry. Microbe-caused spoilage of these raw materials as well as indirect deteriorative effects of these spoiled additives on the machine housekeeping, production and hygienic properties of paper products are well-known problems at the mills." (MENTU, J. et al. 1997. Microbiological Control of Pigments and Fillers in Paper Industry. In: Transactions of the 11th Fundamental Research Symposium in held at Cambridge: September 1997. PIRA International, Surrey,UK).

If we start to examine the routes of microbes into the paper manufacturing processes, mineral pigments and fillers have a role as one of the most important agents to contaminate the paper and board production processes.

This is caused by the characteristic features of these additives: they are (excl. Precipitated Calsium Carbonate) all originated from rocks and contain high counts of soil microbes: spore-forming and other bacteria as well as fungi. Depending of the further treatments of the raw minerals, the quality of minerals will get better or worser. A wide variation of colony counts can be detected in mineral slurries, ranging from 0 to over 10 000 000 cfu/ml!

Biocidic treatment of minerals is a challenging tasks for several reasons. Bacterial spores (very common form of bacteria in minerals) tolerate traditional biocides better than vegetative bacteria; minerals have microbe-covering effects; long transportation and storing periods give extended growth time for microbes etc.

Paper machines need minerals day and night. This everlasting input of mineral-borne bacteria acts as a significant contamination route. Control methods to detect spoiled lots and CCP's of the "coating kitchens" should work very fast and give early warnings in emergence situations as well as documentation of the overall quality of different brands of minerals.

How to build up this kind of reliable mb control for mineral pigments and fillers?

Some new alternatives of traditional, long-lasting and labourious colony count analyses really exists today.

A paper machine can be regarded as an ECOSYSTEM, whose conditions are very stable because the strict adjustments of the process. It also acts as a BIOREACTOR with a continuous supply of nutrients and output of aged culture with its metabolites.


An essential feature of a paper machine process is its environmental stability (temperature, pH, redox potential, nutrients, stimulative and inhibitive factors etc.) which leads to the development of a selected, accommodated microbial populations in ecological "niches" all over the machine. The risk of microbial problems cannot usually be taken into account when optimizing these controls. This can lead to an active, waterborne population of various bacteria with total counts of even 1000 000 000 cfu/ml. Many essential raw materials of the paper production like starches, mineral fillers and coating paste components have also beneficial effects on the growth and activity of microorganisms.


These microbiological problems get ever worse by the formation of biofilms and slime layers. Aged biofilms are not only restricted sites of microbial growth but they also release bacteria and bacterial spores into the water circulations of the paper machine.


Storage tanks of raw materials can be regarded as batch fermentors where the typical growth steps LAG, LOG, STAT and KILL can be detected during extended storing periods. A paper machine itself acts like a continuous culture bioreactor or a chemostat, securing stable growt environment of the process-adapted microbial population.

Microbiology for Pulp and Paper Industry

What is a paper machine? A tool to produce paper, obviously. But what else?

It is also an ECOSYSTEM and a BIOREACTOR.

- More interesting facts about the secrets of paper machine environment coming soon...