SOLVING SLIME IN PAPER AND PULP INDUSTRY

1. BIOTECHNOLOGY IN
SOLVING OF SLIME
PROBLEM
DR. ESTHER SHOBA R
ASSISTANT PROFESSOR
KRISTU JAYANTI COLLEGE

2. INTRODUCTION
• A well known and longstanding problem in paper manufacture is the proliferation
of biological slimes on machinery.
• The process conditions of paper mills are favorable for the reproduction of slime
forming microorganisms because of the nutrients ,temperature, and moisture.
• The slime formation occurs due to growth of microorganism like fungi ,bacteria
etc.
• Fiber based paper mills using closed processes have optimal conditions for
growth of the organism due to high nutrient level ,optimum temperature and pH.

3. MICROORGANISM
S RESPONSIBLE
FOR SLIME
FORMATION IN
PAPER INDUSTRY

4. THE PROBLEMS IN PAPER MILL
Different types of losses happens in paper industries due to the formation of slime,
such as:
• Production of dangerous gases(hydrogen, methane etc)
• The microbial growth causes spoilage of raw materials and additives used during
paper making.
• Reduction in quality( slime spots, holes, odors in paper products)
• Loss of production.

5. SLIME CONTROL
Biocides :Using of these biocides became a part of the paper and pulp
industry.
• Properties : Cheap , efficient, and should not disturb the paper making process.
• Biocides are divided in 2 types :-
Oxidizing biocides : Sodium bromide , ammonium sulfate.
Nonoxidizing biocides : 2-Bromo-2-nitropropane-1,3-diol, Diethyldithicarbamate.

6. Cleaning :-
• To control the slime, mechanical cleaning and boil out at extreme pH levels and
high temperature.
• Cleaning is often done with high pressure water flushing.
• Mechanical cleaning and boil out are often impracticable, and can be costly they
usually involve equipment down time.

7. HOW BIOTECHNOLOGY IS SOLVE THIS
PROBLEM
Biosurfactants :-
• The term biosurfactant has generally been used to refer to any compound which
has some influence on interfaces.
• The best characterized lipopeptide surfactants are SURFACTIN, which has been
isolated from several strains of Bacillus subtilis and Bacillus pumilis, VISCOSIN
which is produced by Pseudomonas fluorescens, and ARTHROFACTIN produced
by Arthrobacter sp. Strain MIS38.

8. • Surfactin produced by Bacillus subtilis ATTC 21332 is one of the most effective
biosurfactants known.
• Biosurfactants are involved in cell adhesion, emulsification, dispersion,
flocculation, cell aggregation etc.
• Biosurfactants are biodegradable, potentially less toxic tan the synthetic
compounds currently used and can be produced from a variety of substrates.

9. ENZYMATIC SLIME DEPOSIT CONTROL
• Nowadays research is focused on both the prevention and disruption of biofilm
build-up caused by slime-forming species of bacteria, yeasts and fungi.
• The use of enzyme in the control of microbiological slime deposits, particular
EDC-1(enzymatic deposit control) developed by Hatcher has proved useful under
modern mill conditions.
• EDC-1 is an enzyme that hydrolyses and depolymerizes the fructose
polysaccharide Levan, which has been identified in paper mil slime.

10. • It is non-toxic does not promote resistance, does not accumulate in the system as
it is in activated at 80-100°C and is safe to handle.
• The reason is that EDC-1 is a specific Levan- hydrolyzing enzyme ,i.e., it is
restricted to Levan-producing bacteria which have been shown to be secondary
factor in many process waters.

11. BIO DISPERSANTS
• Bio dispersants play an essential role in modern programs to control biofilms
caused by excessive growth of micro-organisms such as bacteria, yeast and
moulds.
• It is based on the non-ionic polymers, which are non-toxic, non foaming, colorless
and free of organic solvents.
• Because of their non-ionic character they will neither increase the system
anioncity nor interfere with other papermaking chemicals.
• It has no pH limitations.

12. • Slime not only deteriorates paper but it protects bacteria from biocidal conditions and
biocides by making penetration of biocides to cell mass difficult,
• Therefore, an alternative has been developed that employs slime dissolving enzymes.
• Once the slime has been digested away the cells are then directly exposed to the
biocide which is now effective at lower concentration.
• The slime, which is a fructan polymer, is broken down to monomers by carbohydrase
type of enzymes
• There are two types of enzymes involved in fructan degradation-hydrolases and
transferases. The hydrolytic enzymes, according to their mode of action, are either
endo- or exo-enzymes, producing a homologous series of oligofructans or only fructose,
respectively.
• The transferases, on the other hand, split off fructose dimers and by simultaneous
transfructosylation give rise to difructose anhydride.

13. • Several microorganisms producing levan degrading enzymes have been isolated from
various sources.
• The organisms include: Bacillus stearothermophilus, B. cereus, B. cereus var.
mucordes, B. megaterium, Aerobacter aerogeries, lkwinia herbicola, Serratia
marcescerls ; Micrococcus spp., Pseudomonas spp., Streptococcus spp. (hemolytic);
• Lactobacillus plantarium, Streptomyces cyanoalbus. Streptomyces voleus [%I],
Arthrobacter ureafaciens; and Rhodotorula sp
• Levanases from Streptomyces sp. no. 7-3, BaciNus sp. no 71 and Rhodotorula sp.
have been purified and their molecular weights are found be 54, 135 and 39 kDa,
respectively. The enzyme of Streptomyces sp. no. 7-3 and Streptomyces exfoliates F3-
2 [61] have been found to hydrolyze levan to produce levanbiose.
• Levanase from Bacillus sp. produces levanheptose as the predominant product.

14. • Cloning of this enzyme has been attempted in various organisms. The Bacillus subtilis
levanase has been cloned in Escherichia coli and Saccharomyces cerevisiae
• Combined treatment with 20 ppm methelyne-bisthiocyanate (MBT) and 40 ppm levan
hydrolase has been shown to lower the colony count of Aerobacter Ievanicum and
Bacillus subtilis from 109 and 104 CFU/mL to 106 and 103 CFU/mL, respectively.
Whereas against Rhodotorula glutinis the use of 10 ppm MBT and 40 ppm enzyme
decreased the colony count from 104 to 10 CFU/mL.
• Further it was shown that on application of enzyme (0.10 kg/metric ton) on machines
producing printing grade paper, the biocide concentration could be reduced from 0.13 to
0.02 kg/metric ton.
• The amount of biocide was reduced to -15% of what had been employed prior to using
the enzyme.
• A similar level of reduction in biocide concentration was achieved in the whitewater
system of a paper mill when an enzyme preparation was deployed

15. • Patterson reported that with the use of enzyme, the concentration of biocide may be
reduced only by 50% and slime breaks are reduced from three per day to three per
month.
• Similarly, Colasurdo and Wilton [13] noted that with the use of an enzyme preparation
at SONOCO Products Co., Hartsville, U.S.A., the slime breaks were virtually eliminated,
leading to increased productivity.
• Another enzyme product NOPCO EDC-1 is in common use in the United States, Japan,
Britain, and Scandinavia for improved control of slime with reduced biocide levels.
• This strategy has improved paper quality by reducing the number of holes and splits
during manufacture.
• The levanase enzyme produced by Rhodotorula sp. has also been found to reduce the
needed biocide concentration by 25% without adversely affecting the paper properties