Assessment of a Thermostable Xylanase from Paenibacillus sp. ASCD2 for Application in Prebleaching of Eucalyptus Kraft Pulp

Abstract

Cellulase free thermostable xylanase from Paenibacillus sp. ASCD2 was used to evaluate its applicability in prebleaching of eucalyptus kraft pulp. Pretreatment of eucalyptus kraft pulp with crude xylanase (40 U per gram of dry pulp) at 60 °C for 3 h showed 21.8 ± 0.04 % reduction in kappa number of kraft pulp along with release of 17.4 ± 0.36 mg/g reducing sugars. Increase in the absorbance at 237 and 465 nm during biobleaching of kraft pulp indicated release of chromophores and hydrophobic compounds from the pulp fibres respectively. Scanning electron microscopic studies indicated that there was increase in opening of the microfibres, swelling, separation and loss in packness of the pulp fibres of xylanase pretreated chemically bleached pulp. The results of the present study proved that xylanase treatment prior to chemical bleaching can reduce the use of chemicals for bleaching of pulp in paper pulp industry.