EFFECT OF TWO FUNGAL STRAINS OF COPRINELLUS DISSEMINATUS SH-1 NTCC-1163 AND SH-2 NTCC-1164 ON PULP REFINING AND MECHANICAL STRENGTH PROPERTIES OF WHEAT STRAW SODA-AQ PULP

摘要

Effect of novel cellulase-poor crude enzymes from two different strains of C. disseminatus - SH-1 NTCC-1163 (enzyme A) and SH-2 NTCC-1164 (enzyme B) - produced under solid-state fermentation (SSF) conditions, on both pulp beating and mechanical strength properties of wheat straw soda-AQ pulp bleached by CEHH, TCF and ECF bleaching sequences, was investigated. X~AECEHH and X~BECEHH pulps bleached at 4% chlorine demand required 66.66 and 30.30%, respectively, fewer PFI mill revolutions, to attain a beating level of 40 °SR, compared to the control. Tensile and burst indexes of X~AECEHH pulp decreased by 10.74 and 6.94%, whereas the number of double folds and tear index improved by 8.63 and 0.73%, respectively, compared to the control. The X~AECEHH and X~BECEHH pulps bleached at 2.5% chlorine demand required more PFI revolutions, while the decrease in mechanical strength properties was lower, compared to X~AECEHH and X~BECEHH sequences bleached at 4% chlorine demand. On the contrary, OX~AEDED, OX~BEDED, OX~AEDEP and OX~BEDEP bleached pulps required more PFI revolutions compared to their respective controls, due to the removal of the low DP xylan content, as a result of xylan removal during oxygen delignification. OX~AEDED and OX~BEDED bleached pulps showed a decrease in tensile and burst indexes and in the number of double folds, as well as an improvement in the tear index, while the decrease in strength properties was observed less in OX~BEDED bleached pulp. The OX~AEDEP and OX~BEDEP bleaching sequences followed the same pattern.