STUDIES ON APPLICATIONS OF ENZYMATIC PREBI,EACHING IN AGRO-BASED PAPER INDUSTRY

Abstract

The impact of commercial xylanase (novazyme) on soda pulps of wheat straw (tritiurn aestium) and Sarkanda (sacchararn munja), Mixed were studied on different uleaching sequences. CEpH1H2 and CEPEPH bleaching sequences studied. Experiments were performed on wheat straw, Sarkanda and Mixed pulps to analyze the data on enzymatic prebleaching and to understand the manner by which the xylanase works on the substrates. A target brightness of 80% ISO is achievable for three raw materials such as wheat straw, Sarkanda and Mixed pulps using CEVHIH2 and CEPEpH sequences .Higher brightness (84.5`%%% ISO) can he ;ichleved in three pulps using the CEpE1,II sequence. 701,11 bleach chemical _consumption for different sequences followed the order CErHiH2>CF}'El,l-l. BOD and COD also follow the same order but the AOX is lowest for CEPEPH sequence and the highest for CEPHIH2 sequence. The CEYH1H2sequence shows the lowest strength properties compared to CEPEPH sequence. The xylanase prebleaching is possible for the three pulps i.e. wheat straw, Sarkanda and Mixed .the optimized conditions of xylanase prebleaching are different for different pulps .there is a minor decrease in kappa number ,small increase in pulp brightness just after xylanase pretreatment for thee pulps. There is a substantial decrease in bleach chemical consumption of xylanase-pretreated pulps compared to untreated pulps to obtain 80% ISO pulp brightness. The saving in bleach Chemicals of xylanasc-pretreated pulp for sequence (CE1,E1,H) was lower compared to the CEpHIH2 sequence. At the same bleach chemical dose, xylanase pretreated gave pulps of higher brightness as compared to pulps without xylanase pretreatment. AOX values of combined effluents from xylanase-pretreated pulps are lower for different bleaching sequences. The BOD, COD, and BOD/COD of combined effluents are higher for xylanase-pretreated pulps compared to non-xylanase treated pulps.