of Biotechnology in Pulp
and Paper Industry
Pratima Bajpai* and Dr. Pramod K. Bajpai**
of environment friendly processes is becoming more
popular in the pulp and paper industry and therefore
biotechnological processes are coming to the forefront
of research. Biotechnology is defined as the use of
biological organisms/ systems and processes for
practical or commercial purposes. In this broad sense,
biotechnology encompasses a diverse array of activities
including fermentation, immobilized cell and enzyme
technology, cell and tissue culture and monoclonal
antibody techniques; although in recent years, the term
has been increasingly identified with techniques for
genetic transfer and DNA manipulation, namely genetic
engineering. The attractiveness of biotechnology lies in
its potential to provide processes/ products where
non-biological processes are impractical, to increase
specificity in reactions, to provide less
environmentally deleterious processes , to save
energy , and by virtue of the foregoing, to decrease
cost. The raw material in forest-based industries is
wood and its components. Thus, possibilities for
employing biotechnology in these industries are numerous
as one of nature’s most important biological processes
is the degradation of lignocellulosic materials to
carbon dioxide, water and humic substances. In fact,
biotechnology has been used in the paper industry for
quite some time. Wastewater treatment systems for
removal of oxygen-demanding substances and suspended
solids, fermentation of sulphite liquors and preparation
of starch for paper sizing have long been part of the
industry. Improvement in fibre supply by selection of
superior trees is still being carried out by forest
product companies. Even the control of slime and
deposits on paper machines can be considered as an
aspect of biotechnology. However, during last few years,
biotechnologists have sought specific applications for
microorganisms/ enzymes in the pulp and paper industry.
This article reviews the past success and future
possibilities for biotechnology in the pulp and paper
the time, when biotechnology was developed for the pulp
and paper industry i.e. in the mid 70’s, our knowledge
about the enzyme mechanisms involved in the degradation
of wood and its component was in its infancy. The
suggestion, at that time, to use enzymes in pulp and
papermaking seemed out of reach. Production of the
required enzyme quantities at a price that would have
been close to economic feasibility was impossible.
However, since then enormous progress has been made in
the biosciences in general i.e. in genetics, molecular
biology, biochemistry and microbiology. This has allowed
for production of enzymes at economically feasible
process, which has made them technically interesting for
the industry. Enzymes from alkaliphilic and thermophilic
microorganisms can now be cloned into efficient
production systems and enzymes for bleaching, enzymatic
deinking and other papermaking processes can be produced
at costs we could hardly envision 10 years ago.
Microorganisms can now be genetically changed to make
them ideal for specific purposes and enzyme can be
designed to better catalyze industrially important
reactions. The massive amount of efforts devoted over
the past few decades to a better understanding of the
enzymes produced by wood degrading microorganisms for
conversion and degradation of lignin, cellulose and
hemicellulose have provided a fresh base for successful
development of biotechnology in pulp and paper industry.
Due to above advances, the
current state of the art of biotechnology in pulp and paper
industry has improved tremendously over the last decade and
several new biotechnology markets have been developed. One such
development is the use of xylanase in bleaching of kraft pulp.
This technology has been successfully transferred to full
industrial scale in just a few years. The use of xylanase
degrading enzymes to aid in the bleaching of chemical pulp was
introduced by Viikari et al. . Xylanases are indirect
tools for lignin removal. There are many different hypotheses
for how xylanases act and aid in pulp bleaching. A thorough
discussion of these hypotheses and theories has been published
. This technology is now in use at several mills worldwide.
Use of xylanase enzyme can sometimes reduce chemical bleaching
costs by upto 20%. For chlorine based bleaching technologies,
xylanase pretreatment of kraft pulps has also been shown to
reduce the AOX discharges by 5-20% depending upon wood furnish
and mill pulping conditions. The use of a xylanase stage into
commercial TCF bleaching operations has also been successfully
implemented. One such example is the Enzone process, which
bleaches hardwood pulp to full brightness in the sequence OXZP
and softwood pulp in the sequence OXEPZP . The xylanase stage
contributes to the high brightness which, after the full
sequence is 5-8% ISO higher as compared to when the xylanase
stage is not used.
methods for degradation of pitch have found application in
sulphite and TMP mills. Treatment of wood chips in the chip
piles with specific resin degrading fungi is one method and
another method is to use lipases. Lipases have been used in mill
operations to control pitch build up in the white water systems.
Different lipases have been used for removal of pitch. Few
commercial preparations of lipases for pitch removal are
available. The enzymatic pitch control method using lipase was
put into practice in a large-scale papermaking process as a
routine operation in the early 1990s and was the first case in
the world in which an enzyme was put into practice in a
large-scale papermaking process [chapter 2 of reference 1].
Lipases have also found a market for deinking applications in
cases where the inks contain vegetable oils in their
Polymers used in laser and
xerographic printing have made conventional deinking methods
inadequate for recycling to produce high quality paper.
Recycling mills are, therefore, increasing dependence upon
mechanical devices for breaking down the large, non-impact ink
particles to be able to remove them by flotation or washing.
These intensive mechanical forces are energy demanding and
shorten the fibers decreasing freeness and strength of the paper
formed from these fibres. Mixtures of enzymes, mostly cellulases,
have therefore been implemented to substitute for chemical
deinking of such furnishes. Other furnishes, such as old
newsprint (ONP) and old magazine (OMP) are also successfully
deinked using mixture of enzymes. Using the so-called Enzynk
process, developed at the University of Georgia, it was found
that all kinds of recycled paper could be successfully deinked
. Some type of furnishes need a large variety of enzymes,
others less multiple enzyme components. The company Enzymatic
Deinking Technologies (EDT) with offices and laboratories in
Norcross near Atlanta, Georgia was founded in 1994. The company
has commercialized the enzymatic deinking technology in pulp and
paper mills in United States, Europe and Asia and the market for
this technique seems to be growing very fast. At present,
enzymatic deinking is one of the most promising and viable
biotechnologies in the pulp and paper industry. Enzymatic
deinking has the capability to reduce the dirt count and
stickies and to increase freeness of the pulp to a much greater
extent as compared to conventional chemical pulping.
1: Enzymes investigated for bleaching of wood pulp
||Degradation of xylan
|Laccase plus redox mediators
||Oxidation/ polymerization of lignin
||Oxidation/ polymerization of lignin
||Depolymerization/ repolymerization of lignin
quinones, phenoxy and cation
The pulp and
paper industry has invested enormous amounts of work and money
to abandon at least molecular chlorine and to develop more
environmentally benign bleaching processes. Oxygen based
chemicals such as O2, O3 or H2O2 in combination with enzymes can
be employed for bleaching of pulp and the use of these enzymes
in these processes is practically a hot area of research (Table
1). As expected, the phenol oxidase, laccase, manganese
peroxidase (MnP) and lignin peroxidase (LiP) are possible enzyme
candidates in pulp bleaching processes. Of these, laccase
combined with redox mediators is probably the most interesting
and it became clear in the recent 8th International Conference
on Biotechnology in Pulp & Paper Industry that a race is on
involving laboratories in several countries to develop a
bleaching stage using laccase plus redox mediators into
One biotechnology-based process
close to commercialization is biopulping. For pulp and paper
production, wood chips are stored in chip piles for various
lengths of time depending on their future fate. While fresh
chips are prepared for kraft pulping, somewhat larger storage
times are normally required for chips aimed for sulphite or
mechanical pulping. Delignification of chips prior to further
processing is desirable both in chemical or mechanical pulping
for savings of energy, chemicals, treatment time etc. The
delignification is particularly desirable in production of
mechanical pulp since it is very energy demanding process. To
obtain specific lignin degrading fungi, researchers at the
Swedish Pulp and Paper Research Institute in Stockholm directed
considerable efforts towards developing cellulase less mutants
of white-rot fungus Phanerochaete chrysosporium. However,
a more thorough investigation on the feasibility of
biomechanical pulping was started in 1987 at the Forest Products
Laboratory (FPL) in Madison, Wisconsin. A comprehensive
screening program was initiated to select fast-growing white-rot
fungi able to selectively remove lignin from wood. Cereporiopsis
subvermispora was found to be the best suited for this
purpose and has been used in large-scale outdoor delignification
of a 50 metric ton chip pile at FPL. In this test about 30%
energy was saved and the quality of the paper from the
pretreated chips was better than that from the non-pretreated
chips . Efforts are being made to commercialize the process.
Fungal treatment for kraft pulping of eucalyptus has been
recently studied, the results of which show promise for an
improved process . Fungal treatment reduced the pitch content
in the wood chips and during kraft pulping, reduced the active
alkali requirement upto 18%, reduced the total cooking time by
upto 33% or reduced the sulphidity requirement of the
white liquor by upto
30%. The quality of the resultant biopulp was better than that
of the control. The bleached pulps were easier to refine than
the reference pulp.
pulp drainage with enzymes (mixture of cellulase and xylanase
enzyme) is practiced routinely at mill scale. Several commercial
enzymes are available which improve the drainage of secondary
fibres. Ciba-Geigy and its partner Genencor have conducted more
than 100 plant scale trials. The outcome is several regular
customers worldwide. Cellulase and hemicellulase enzymes are
also found to reduce energy requirement during refining of
chemical and mechanical pulps. At the moment, the process is not
economically viable. However, with rising power cost and a
possible reduction in enzyme cost in the near future, the
process seems to have great potential. Mills, that are currently
throughput limited because of refiner power limits, may assign
substantial value to the removal of bottlenecks provided by
Pectinases and hemicellulase
enzymes are found to reduce energy requirement as much as 80%
during debarking. One of the major difficulties with enzymatic
debarking is the poor infiltration of enzymes in the cambium of
whole logs. Pectinase and xylanase have been also used in
processing plant fibre sources such as flax and hemp. At
present, the fibre liberation is affected by retting.
Replacement of slow natural retting by treatment with artificial
mixture of enzymes could become a new fibre liberation
technology. A patent of disclosure from Honshu Paper Co.
described the use of commercial cellulases to enhance the
flexibility of hardwood vessels . Enzyme treatment reduced
vessel picking by 85%. At the same time, smoothness and tensile
strength increased and drainage time also increased. A novel
enzyme formulation, Shivex, which is basically a xylanase
enzyme, can be used to increase the efficiency of shive removal
by bleaching. By treating brown stock with Shivex, mills
can increase the degree of shive removal in the subsequent
bleaching by 50%. At a given bleached brightness, Shivex
treatment results in a lower shive count. Enzyme treatment,
therefore, helps to remove shives from the pulp beyond the
associated gain in the brightness. Removal of shives and ease of
pulp bleaching by the use of enzymes also help in reducing the
2: Biotechnology in pulp & paper industry: Current status
||Biological depithing of raw material
pitch removal from wood chips
||Enzymatic pitch removal from pulp
||Xylanases for pulp bleaching
||Improvement of pulp drainage by enzymes
||Production of dissolving pulp using xylanase enzyme
||Biofiltration for control of odorous emissions
||Improving beatability of pulp with enzymes
||Pulp bleaching with lignin oxidizing enzymes
||Biopulping - mechanical/ chemical
de-toxification of bleach
||Enzymatic retting of flax fibres
Table 2 presents
the current developmental stages of various biotechnological
approaches for use in the pulp and paper industry. While many
applications are still in the research and development stage,
several new applications have found their way into the mill in an
unprecedently short period of time. In addition, some of these new
developments in biotechnology, if successful, could have a
profound impact on the future technology of the pulp and paper
commercial application of biotechnology in pulp and
paper in India started with the modification of starch
for surface sizing of paper. Thapar Centre for
Industrial R&D (TCIRD), Patiala carried the
developmental work in the 1980s and the process
technology is in use in few paper mills since 1992. A
similar process of enzymatic modification of starch was
also developed by TCIRD for lamination of paperboards,
which was brought to the mills in mid 1990s.
The second application
of biotech process in Indian pulp and paper industry is
xylanase pre-bleaching of pulp. Extensive R&D work
on enzymatic prebleaching of pulp from Indian raw
materials and manufactured according to pulping and
bleaching processes prevalent in India, was done by
TCIRD in early 1990s [11-16]. The first ever mill trial
on xylanase pre-bleaching in India was conducted in a
pulp and paper mill of Ballarpur Industries Ltd. (BILT)
in 1992 using acidic xylanase enzyme, produced by M/s
Biocon India Pvt. Ltd. Subsequently, several other mill
trials were organized in different mills using different
types of raw materials and practicing different pulping
and bleaching processes, using xylanase enzymes of
different qualities (including alkaline and
thermotolerant ones). Due to pressure on reducing
organochlorine compounds (AOX) in the effluents ,
more and more pulp mills are getting interested in this
process and have also started taking mill trials.
Century Pulp and Paper , Grasim, Central Pulp and
Paper Mills, Star Paper Mills, Shreyans Papers and
Varinder Agro Paper Mills
and Varinder Agro Paper Mills are worth mentioning.
First ever process on the use of xylanase enzyme for the
production of high quality dissolving pulp has been
developed at TCIRD . By this process, a pulp of
better optical properties and reactivity is obtained
which also results in higher viscose yield. The process
has been transferred to a pulp mill and an Indian patent
is pending for the same.
the thermostable alkaline xylanase enzymes are available
in India from M/s Novozyme South Asia Pvt. Ltd., Biocon
India Pvt. Ltd. (in collaboration with Rohm Enzyme Oy,
Finland), Advance Biochemicals Ltd. (in collaboration
with BIL, Australia). Earlier Esvin Biotech has also
tried to produce xylanase enzyme, in collaboration with
BIL-Australia, for pre-bleaching of pulp, which could
not see the light of the day. Recently, M/s J.K. Pharma
has also started promoting alkaline xylanase enzyme and
M/s Khandelwal Laboratories Ltd. is scaling up the
xylanase production with partial financial support from
Depart of Scientific and Industrial Research (DSIR),
Ministry of Industries, Government of India.
R&D work on isolation and screening of microbial
cultures, capable of producing low molecular weight
xylanase enzyme, was done at National Chemical
Laboratory Pune in early 1990s, further progress could
not take place. Lately, IIT Delhi, Birla Institute of
Scientific and Industrial Research Jaipur and few other
research and academic institutions have started working
on culture development for the production of alkaline
thermotolerant xylanase enzymes. A national research
laboratory - Central Pulp and Paper Research Institute (CPPRI)
and a premier educational institution in the country -
Institute of Paper Technology (IPT) have also initiated
R&D on xylanase enzyme pre-bleaching of pulp.
works on improving the drainabilty and refining of pulp
(virgin as well as recycled) using enzymes have been
carried out at TCIRD [20,21]. These processes are still
to be commercialized in India for the want of their cost
effectiveness. R&D on enzymatic deinking of recycled
paper has been initiated at TCIRD . Efforts are on
at TCIRD and few other organizations on deinking of
mixed office waste and other waste papers.
R&D project on the development of lignin oxidizing
enzymes and its use in delignification of brown stock
has been started recently at TCIRD with the financial
supports from Department of Science & Technology
(DST), Government of India and Ballarpur Industries Ltd.
The laboratory work on
bio-pulping of Indian raw materials was initiated in
1995 at TCIRD, Patiala in collaboration with Forest
Products Laboratory, Madison, Wisconsin (USA)/
Bio-pulping International Inc. (USA). A technically
sound process has been developed for biokraft pulping of
eucalyptus , for which a world patent under PCT was
applied in the year 1998 and subsequently to several
countries including India and USA. Now, the efforts are
on to commercialize the process. Recently, Indian Agro
Paper Mills Association (IAPMA) has shown interest on
bio-chemical pulping of agri-residues. Based on the
encouraging laboratory results with bagasse and wheat
straw at TCIRD, further R&D work has been done with
wheat straw. Now, IAPMA and TCIRD are arranging for the
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