Hemicellulase-aided bleaching is the first full-scale biotechnical application in the pulp and paper industry which truly exploits the unique specificity and safety of. () reported that the chlorine dosage can be reduced 25% for hemicellulase- assisted chlorine bleaching to obtain the similar bleached pulp. Paice et al. Elemental chlorine, while effective in bleaching pulp and low in both primary classes: hemicellulases (xylanase) and oxidases (laccase).
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Visit for more related articles at Journal of Industrial Pollution Control. Biotechnological techniques like molecular biology, enzymes engineering, genetic engineering genomics, proteomics, metabolomics and bioinformatics etc.
Biotechnology increases the cost efficiency, develop environmentally feasible processes and improves the product quality. Indian paper industry contributes to about 2. The industry uses variety of raw material viz. Paper is manufactured from pulp by sulphite and sulphate process. The main pulping process used globally is the kraft process Hemicellklases. Dahl in C.
Biermann, Handbook of Pulping and Papermaking, Bark of wood is removed. The logs obtained are cut into smaller pieces called chips.
Hemicellulases in the bleaching of chemical pulps.
The chips are cooked by heating under pressure using caustic soda and sulfur. By this lignin that binds the cellulose fibers are removed. This is the chemical pulping process. In mechanical pulping, debarked logs are forced through rotating toothed steel discs. The discs tear the logs and remove the lignin. The lignin degraded gives paper a brownish tinge which are used for printing newspapers http: Biopulping is the treatment of wood chips with lignin- degrading fungi.
It is used prior to mechanical pulping of wood. It eases subsequent mechanical and chemical pulping. Biopulping reduces the demand for energy and chemicals, hemicellulxses paper quality, and decreases the environmental impact of pulp production Pullman et al.
Biotechnology, silviculture, trees and other bioresources can be used to enhance the properties required in cellulose fibers Buschle-Diller and Ren.
Genetically engineered microorganisms and enzymes can displace many of the environmentally adverse practices used in pulp processing http: Fungi such as O.
This is applied before carrying out the normal mechanical or chemical pulping. It reduces the overall energy requirements for mechanical process and reduces the quantum of chemicals for chemical pulping. Chlorine is used for bleaching process which has a huge polluting potential. Pulp is usually tinged with brown color due to lignin content.
Enzyme enhances this bleaching process by two ways. Xylase breaks down the carbohydrate xylan this entraps pulp lignin to reduce the need for chlorine in bleaching but gives numbers of byproducts dioxins and PCBs. Xylanase treatment is used to reduce the consumption of chlorine dioxide and associated costs.
Thermostable microbial xylanases are active under alkaline conditions of pulping are generally preferred for biobleaching Raghukumar, They save production costs and prevents formation of unwanted products during pulp bleaching process. It saves chlorine leading to lower chemical costs and reduction in toxic effluents.
It has also reduced chemical bleaching costs. Higher brightness ceilings have been achieved with an X-stage for a variety of bleach sequences. Oxidative enzyme such hemicelllulases laccase is also used pjlp reducing costs in pulp mills. Lipases are hemicellulzses to control deposits of pitch.
Cellulases are used to improve rates of dewatering of pulp; and pectinases for digesting pectins. Cellulases are used for drainage Foster,deinking Bhardwaj et al. Fungal and enzyme pitch degradation products are used in some Pu,p Gehlhoff, and sulfite mills Fleet et al.
Enzymes control the properties of the pulp fiber and, therefore, the end product. Hydrophobicity of fiber surfaces can be altered by the enzyme laccase Wright, Catalase is used to convert residual hydrogen peroxide to water and oxygen. Bleached fibers need be rinsed only once.
The enzymatic process saves water and energy and the effluent is ecologically harmless. The other enzymes such as laccase and manganese peroxidase have also been used.
Role Of Biotechnology In Pulp And Paper Industry | Open Access Journals
The laccase is blfaching for direct delignification of pulp, enabeling replacement of current bleaching chemical stages such as oxygen or ozone stage. Biobleaching of pulp with enzymes have several advantages like: It enhances fibrillation to give stronger paper Eriksson, Biobleaching eliminates few of hemicelulases steps, thereby simplify and reduce the severity of treatment of wastewater.
Lipase has been used to bleachijg pitch buildup. It has also been beaching for deinking applications in cases where the inks contain vegetable oil formulations Sharyo et al. Recycled paper fibers has to undergo deinking process to remove whatever ink that gets fused on to the paper during printing. Cellulase enzymes are used for this deinking process. This makes the use of recycled paper as a viable option to reduce the number of trees needed to be cut to make paper.
A deinking process involving sodium hydroxide, flocculants, dispersants and surfactants is used widely currently. The alkali can make the treated pulp yellow and, consequently, hydrogen peroxide is used subsequently to bleach the alkali deinked pulp. In addition, alkaline deinking diminishes the strength of the pulp fiber and the chemicals used contribute to environmental pollution.
An enzyme-based biotechnology alternative to chemical deinking is being developed. Lignin chain of galacturonic acid that binds the cellulosic pupp can be reduced by making GM trees with less of hemicellulaxes but wood with less of lignin degrades quickly to release more carbon dioxide into the atmosphere.
Deforestation is a matter of concern for both the environmentalists and the paper industry this has forced. Biotechnology can be resourceful in: It is also required to develop low capital pulping and bleaching technologies, simplified pulp bleaching operations, elimination of the inorganic recovery systems for the production of chemical pulps. Biotechnology can be also helpful in development of biofilters to control and hemicellulasees soluble organic and inorganic materials in the white water, to control microbial growth in the water systems of a paper machine and development bleavhing bio-systems to improve drainage and retention control.
Biotechnology can play a leading role, including: Improved deinking and de-starching technologies, to increase drainage, strength, and other physical properties of recycled paper.
Lignin fragments, resin acids, and other low molecular weight compounds which are released during chipping and pulping can be used to generate value-added products.
US5591304A – Method for the use of enzymes in bleaching paper pulp – Google Patents
Genetic plant engineering used to improve the strength, yield, and bleachability of mechanical and chemical pulps Merkle and Dean, The biotechnology is not as helpful in paper as in textiles Chen et al.
Enzymatic systems are catalytic, highly selective, and operable under mild temperature and pressures. Use of enzymes can modify the fiber material. Since they are proteins and work under mild condition of temperature and pH, their use is restricted to various stages at pulping level and bleaching level.
Lignocellulosic material can be degraded by a set of different enzymes like cellulases, swollenins and expansions, cellulolytic, hemicellulolytic and ligninolytic enzymes. Hemicellulases is also well established with the same general trends. Many other enzymes like hydrolytic enzymes, oxidoreductases are now emerging as an important one. The trends, can be clearly seen in Fig. Enzymatic modification of fiber, modify the surface, improved fibre properties and creates completely new fibre characteristics.
It also improves the runnability of the pulping, bleaching and papermaking processes. In the enzymatic process, cellulase and hemicellulase enzymes are mixed with the paper pulp. The enzymes hydrolyze some of the surface sugars on the pulp fiber and this releases the ink particles bound to the fiber.
Role Of Biotechnology In Pulp And Paper Industry
Washing and draining of the pulp remove most of the ink. Any remaining ink is removed during a conventional flotation step. Treatment with alkali is not used and this eliminates the need for subsequent bleaching with hydrogen peroxide. Production of paper consumes huge amounts of water which needs to be hdmicellulases.
Wastewater recycling potentially saves on the expense of treating any freshwater entering the mill and on reduces the environmental impact of effluent disposal. Enzymes can facilitate dewatering of pulp and removal of contaminants without reducing the strength of the recycled pulp fibers. Speedier dewatering improves sheet formation and allows faster processing bleachhing paper machine Jackson et al.
Residual enzymes are deactivated during drying of the paper. Enzymatic deinking work with old newsprint and office waste paper. Enzyme treatment effectively removes laser printer and photocopier inks that are mostly found in office wastepaper Prasad, Biotechnology-based processes for paper industry should reduce the capital costs of pulp production, generate higher value fiber resources, lower total manufacturing costs heimcellulases make it commercially feasible.
The issues to be addressed in future are: Social factors like poverty, bldaching, corporate spending are the factors behind low level consumption. The key challenges are poor and technology obsolete, lacking ability in achieving economy scale and lack of skilled labor http: Unprecedented developments in genomics, biotechnology, telecommunications, artificial intelligence, material science, and engineering have provided techno economicaly feasible technologies and products for the pulp and paper industry.
Advantage with the enzymatic route for pulp making is including lesser costs for effluent disposal. Biotechnology has positively impacted on: Keywords Biotechnology, Pulp and paper industry, Pul; recycling Introduction Indian paper industry contributes to about 2.