Title
Mitigation of adsorbable organic halides in combined effluents of wheat straw soda-AQ pulp bleached with cellulase-poor crude xylanases of Coprinellus disseminatus in elemental chlorine free bleaching
Authors
SHALINI SINGH and DHARM DUTT

Received November 15, 2012
Published Volume 48 Issue 1-2 January-February
Keywords Coprinellus disseminates, biobleaching, wheat straw pulp, AOX

Abstract
Novel cellulase-poor crude xylanases from strains SH-1 NTCC-1163 (enzyme-A), and SH-2 NTCC-1164 (enzyme-B) of Coprinellus disseminatus, mitigated kappa number (56.27 and 58.41%) of wheat straw soda-AQ pulp after OXAE and OXBE bleaching stages, respectively. Significant reductions in AOX (25.00 and 22.05%), with a slight decrease in some strength properties, owing to removal of hemicelluloses, was observed. The removal of hemicelluloses was further validated by an increase in pulp viscosity (6.82 and 4.93%), COD (43.15 and 43.15%) and colour (51.99 and 62.99%) for OXAE1D1E2D2 and OXBE1D1E2D2 sequences, respectively, compared to their respective controls. Compared to controls, AOX reduction was higher in OXAE1DE2P (38.75%) and OXBE1DE2P (36.25%) than OXAE1D1E2D2 (25.00%) and OXBE1D1E2D2 (22.05%) bleached pulps, but at the cost of brightness. AOX, COD and colour were significantly reduced on the 6th day of incubation of combined bleaching effluents.