Original Articles: 2011 Vol: 3 Issue: 4
Studies on decolorization and xylanase production on sawdust liquid extract and studies on biobleaching activity by white rot fungi
Abstract
The efficiency of three white rot fungi Trametes versicolor, Lenzites betulina and Polyporus elegans in bringing about decolorization and enhancement of xylanase production was studied using sawdust liquid extract, a crude source of xylan at two different concentrations of 12% and 20%. The selected cultures were proved to be efficient in both decolorization of xylan and production of xylanases. A clear linear correlation between the enzyme production and decolorization was observed. The decolorization percentage increased with increase in enzyme production from 6th to 12th days of incubation. Trametes versicolor showed maximum decolorization and enzyme production at both the concentrations. It showed 100% of decolorization and 900ug/ml enzyme production at 12% and 95% decolorization and 750ug/ml enzyme at 20%. Lenzites betulina and Polyporus elegans showed 90% and 85% of decolorization and 700ug/ml, 650ug/ml enzyme production at 12% while 85% and 80% decolorization with 650ug/ml, 583ug/ml enzyme production at 20 % concentration of saw dust extract respectively. The study of the bleaching and delignifying (kappa number reduction) ability of wood degrading fungi on pulp were also studied. The results obtained revealed that the selected cultures were able to reduce kappa number. Trametes versicolor was able to reduce kappa number up to 10 points, Lenzites betulina and Polyporus elegans upto 6 and 2 points respectively. Xylanase enzyme was secreted during bleaching by all the three white rot fungi. Based on the results it can be interpreted that xylanases enhance the delignification process and therefore the bleaching of pulp.