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Biocatalysis and Agricultural Biotechnology
journal homepage: www.elsevier.com/locate/bab
Biobleaching for pulp and paper industry in India: Emerging enzyme technology Gursharan Singh, Satinderpal Kaur, Madhu Khatri, Shailendra Kumar Arya ⁎ Department of Biotechnology, University Institute of Engineering Technology, Panjab University, Chandigarh, India
ARTICLE INFO
A B S T R A C T
Indian pulp and paper industry is one of the fastest emerging business sector of the country which has shown tremendous growth in last few years. Governments policies are creating sustain pressure on paper industries to preserve the clean and pollution free environment at any price. As a result industries are pondering to replace the chemical bleaching processes with facile bio-based cost e ff ective technologies. Eco-friendly bleaching enzymes like xylanases and laccases have the potential for biobleaching of wood and agro-based pulps at industrial scale. In India, enzymatic prebleaching of pulp is widely being investigated and has achieved favorable outcomes but at laboratory scales only and commercial application of enzymes for the deligni fi cation of pulp is still at budding stage. This article tends to draw the attention on signi fi cant e ff orts which have been continually attributed by indigenous research laboratories and industries to replace the chemical bleaching with enzymes.
Keywords: Biobleaching Eco-friendly Laccase Pulp and paper Xylanase
1. Introduction
Bajpai, 2012). The high organic content (especially in the wood based pulp), coupled with chlorine dioxide used in the bleaching process, results in the production of organo-chlorine compounds, which are fi - nally discharged as bleach e ffl uents in water bodies. These organo- chlorine compounds (measured as Adsorbable Organic Halogens, AOX) have been reported to cause genetic and reproductive damages in aquatic as well as terrestrial animals including humans (Sharma et al., 2014). Although more eco-friendly options for bleaching are open to pulp mills in the form of alternatives to ClO 2 like extended cooking or oxygen, hydrogen peroxide or ozone based deligni fi cation, but im- plementation of these alternates needs process modi fi cations and is considered as cost intensive proposition at large scale. Enzymes provide a simpler and cost e ff ective way to reduce the use of ClO 2 , chlorine compounds and other bleaching chemicals. Enzymes also o ff er the simple approach that allows for a higher brightness ceiling to be reached (Abhay et al., 2018). This can all be achieved without major capital investment. The applications of xylanase enzyme as pre- bleaching agent has been established in several laboratories and has also been commercially exploited in Europe, North America and in few Asian countries (Bajpai, 2012).
Currently Indian pulp and paper industrial units account for ~ 3.0% of the world's production of paper. The estimated turnover of the in- dustry is US$ ~ 8.0 billion. The industry provides employment to more than 0.5 million people directly and 1.5 million indirectly. During 2015 – 16, domestic production of paper was estimated to be 12.2 mil- lion tons (http://ipma.co.in). Paper industry in country is becoming more promising as the domestic demand of paper is increasing due to the growing population and literacy rate, growth in gross domestic product (GDP) and lifestyle of the individuals (Sharma et al., 2015a; Sharma et al., 2015b; Sharma et al., 2015c). The focus of paper industry is now shifting towards eco-friendly production of paper. The paper is produced from pulps generated from wood, agricultural residues like wheat straw or from waste paper. The use of wood based technology is constantly on the decline because of capital and raw material avail- ability constraints. The production of pulp and paper involves three important steps viz. pulping, bleaching, and fi nal paper fi nishing. The removal of recalcitrant lignin from pulp is called bleaching which is necessary for making the bright and white paper. Till the end of 20th century, bleaching of pulps, irrespective of their origin from soft or hard wood, employed large amounts of chlorine and chlorine based chemi- cals. But now most of the pulp and paper mills worldwide use chlorine dioxide (ClO 2 ) as the elemental chlorine free (ECF) bleaching agent for the production of high quality white paper (Dwivedi et al., 2010;
2. Structure of the Indian paper industry
The Indian paper industry recognized as the aggregation of small, medium and large sized paper mills with di ff erent paper making
⁎ Corresponding author. E-mail address: skarya@pu.ac.in (S.K. Arya).
https://doi.org/10.1016/j.bcab.2019.01.019 Received 8 November 2018; Received in revised form 9 January 2019; Accepted 10 January 2019
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