Testing the many faces of bio economics

This frightening picture is reminding me about a blog visualizing microbes and bacteria.

I hope to find those representations soon to have a model.

Nevertheless, we’re going to create our own picture and graphics gallery.

We need to invest time in creating cartoons and images.

There’re tons of pictures describing process technology solutions, but the challenge is to create visual effects to show events that aren’t visible to the eye.

Juha Mentu does have pictures from microscopic “body counts”.

We’ve the artistic freedom to show the mystery of microbial activity with inventive graphical effects.

The need of paper industry biocides: alternative prospects.

IM is wondering: are there any other sector of process industry, where microbes are allowed to grow like in paper industry?

Biotechnological processes, of course. But their populations are carefully selected and controlled. And they are employers of the company, not criminals trying to cause harm to the company.

Some significant changes in paper industry processes have taken place after the rise of active environmental care. Both the closure of water circulation and the cancelling of biocides having mercury as an active incredient are favorable for the environment, of course. But the microbial growth inside the paper machines has activated at the same time.

The beginning of neutral paper production led to an "ecocatastrophe" inside paper machines. The rise of pH value (as well as the rise of temperature, caused by the extended recirculation of water) was fatal for slow, acid-loving fungal growth. New mineral additives are an important source of certain types of bacteria, causing severe problems like production of slime, spoiling of the process compounds and hygiene faults of the products.

IM has published an article "Paper Machine: an Ecosystem and a Bioreactor" (INOCULA 1/2007. Helsinki, Finland). Many readers agree: paper machines offer ecological niches for bacteria, and the controlled environments of wet end circulations are very much similar with those of biotechnical processes, based on chemostatic fermentors.

A lot could be do to make paper machines more unfavorable growth environment for microbial contaminants. Very good results have been achieved in some projects where ecological aspects have been taken into account. These issues will be discussed later in this blog.

But the main question is: how much biocides we still need to control the microbial growth in all regions of a paper machine?

Incoming raw materials, sorry to say, may be very contaminated: the highest value of total count during IM's career has been over 100 000 000 cfu/g in a mineral slurry (which was fortunately replaced by a fresh lot by the supplier!). It is therefore obvious that a continuous control - both analytical and practical - is needed for starches, mineral pigments and other contaminated raw materials. This does not mean that all lots are spoiled: there are suppliers which know their response to deliver pure products to the mills but all kind of errors in biocidic pre-treatment, transport and storage of these products may happen.

Certain sites of paper machines also need biocidic treatments all the time. Chosing proper solutions for biocide programs (type of biocide, active compound, dosing sites, timing etc.) of a paper machine is a challenging tasks. In best cases, both the paper mill and biocide personnel are sitting down and discussing of the individual problems of the paper process hygiene.

When specified laboratory services, having tools like PMEU and biofilm microscopy, are included, the final result can be optimal one. Paper industry microbiologists can also help significantly by declaring the effects of process parameters on the growth of planktonic and biofilm bacteria.

The more competence is included, the better solution will be find.

How to evaluate paper industry biocides?

The following post was sent to "industrymicrobiologist.blogspot.com" but I think that it may interest also the readers of BIOTOUCH blog (and comments, of course, are more than welcome!).

Before referring the originat text, I would like to add some ideas about evaluation of biocides.

As known by microbiologists, traditional plate count methods cause bias into the biocide test results. No matter the active compounds are added to the process samples for KILL tests, final results are still derived by colony count analyses.

To have faster and more reliable evaluation (no need to dose every alternative into the process for days..weeks) a novel test method, which performes the biocide evaluation in original samples all over the test, is needed. PMEU method seems, until now, definitely to be the best choose.

And then the original post:

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 I know, 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 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.

PMEU Incubator as a tool for fast evaluation of slimicides.

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
* 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.

More about this issue: http://www.industrymicrobiologist.blogspot.com/.