%LRFDWDO\VLVDQG$JULFXOWXUDO%LRWHFKQRORJ\ ²
G. Singh et al.
even organic chlorine compounds.
PCR. The 816-bp fragment (toward the C terminus) of the WtLcc was manipulated and enzyme variants (Lcc35, Lcc61, and Lcc62) were chosen best on the criteria of enhanced enzyme activity against ABTS. In this study the mutant laccase variants have the same E0 like the parent WtLcc.
Acknowledgments
Authors are thankful to the SERB/DST, Delhi, India, for providing the research funding under Fast Track Young Scientist Program (SB/FT/ LS-315/2012).
7. Environmental regulations for the paper industry and policy measures
References
Pulp and paper industry presently consuming the large quantities of fresh water, 80 – 150m 3 t − 1 of paper, depends on the type of raw ma- terial being used. Commonly agro based paper mills are expending more water than recycled fi bre (RCF) mills for removing the chemicals from processed pulp. Disposal of waste water contained severely en- vironmental toxic compounds (AOX), bleaching (hydrogen peroxide, chlorine dioxide and caustic soda) and whitening agents (kaolin, cal- cium carbonate and titanium dioxide). Consequences of growing awareness about healthy and clean environment, paper industries fa- cing stringent criticisms from Government as well as from general public due to release of untreated or partially treated e ffl uent (Bajpai, 2012). In response to environmental concerns the paper industry has reacted by making process modi fi cations based on existing and new proven technologies. The Central Pollution Control Board (CPCB) has taken several initiatives for reducing the pollution caused by paper mills, up to 2020. CPCB will make sure that none of the paper industry can discharge untreated industrial e ffl uent to the water bodies like rivers and canals. Some of large paper industries recently upgraded their e ffl uent treatment plant (ETP) with installation of tertiary treat- ment system for better e ffl uent quality, particularly colour and sus- pended solids. Some of the medium sized agro-based paper mills have installed the non-conventional chemical recovery system, to incinerate the black liquor, which is one of the major causes of pollution. E ffl uent from all the operational units is mixed together and collected in e ffl uent treatment plant for a common treatment, this is current practice adopted by most of the small and medium paper industries. This mixing up of all types of wastes poses a problem of handling large volumes of e ffl uents with a variety of e ffl uent parameters. It is suggested that co- loured and non-coloured e ffl uents should be segregated and treated separately thereby reducing the overall chemical load and possibly improving the treated wastewater quality. Therefore, mills may initiate actions to reengineer and modernize the existing ETP to phase out unlined lagoons by providing e ffi cient coagulation and fl occulation processes and converting the existing anaerobic lagoons into a lined lagoon for active aerobic process, thereby avoiding any groundwater pollution problem, improving the quality of treated e ffl uent as well as reducing the holding time (http://psa.gov.in).
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8. Conclusion and future prospects
Irrespective of continuous progress of Indian paper industries, only few of the large wood based paper mills have made progress by adop- tion of new green technologies but fully fl edged, total chlorine free (TCF) bleaching of pulp with cocktail of enzymes is still under ob- servations. ECF and TCF paper production o ff ers opportunities for emerging enzyme technology which provide a simple and cost-e ff ective way to satisfy the consumers and environmental protection agencies ’ concerns. The day may not be far when paper products manufactured with chlorine compound-based technology will be prohibited for wrapping of food products and other consumer items. If industry will not implement the international standards, as a result paper export market may face the undesirable consequences in future. It is also im- perative to generate new technologies for economical xylanase and laccase production. Realistic cost estimate and improvement in process economics shall be the key factors for commercial success of any technology and therefore it must be clearly understood that enzyme- based process for bleaching must be as inexpensive as using chlorine or
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