Effect of Xylanases from C. Disseminatus SW-1 NTCC-1165 on Pulp and Effluent Characteristics during CEHH Bleaching of Soda-AQ Bagasse Pulp

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Author(s) Swarnima Agnihotri | Dharm Dutt | Amit Kumar
Pages 346-357
Volume 1
Issue 7
Date July, 2012
Keywords Coprinellus disseminatus SW-1 NTCC-1165, Sugarcane bagasse, Soda-AQ pulp, Bleaching, Bleach effluent, SEM
Abstract

A new thermo-alkali-tolerant xylanase from Coprinellus disseminatus SW-1 NTCC-1165 produced under solid-state fermentation, mitigated pulp kappa number of sugarcane bagasse soda-AQ pulp by 29.80 and 36.6% after XE and XO-stages respectively, total chlorine charge by 29.70 and 36.53% with brightness increase by 4.4 and 3.7% for XECEHH and XOCEHH sequences respectively compared to their respective controls. The release of reducing sugars and chromophores was the maximum at a xylanase dose of 8 IU/g, reaction time 120 min, consistency 10%, temperature 550C and pH 6.4. The xylanase pretreatment reduced the AOX by 28.16 and 34.65% in combined bleach effluent of CEHH and OCEHH bleaching sequences respectively. In addition, it improved all the strength properties of paper and pulp viscosity by 0.65 (XECEHH) and 2.57% (XOCEHH). Increase in COD and colour in studied bleaching sequences were attributable to hydrolysis of hemicelluloses, release of lignin-carbohydrates complexes after xylanase treatment. Xylanase treatment modifies fibre surface by introducing cracks, peelings, swelling and external fibrillation which facilitates faster penetration of bleach chemicals by extenuating physical barrier as revealed by scanning electron microscopy.

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