Biotechnological Investigation of lignolytic Potential of Rigidoporus sp DK4

Abstract

Laccase has wide application in industries like textile dye bleaching, pulping and bioremediation, due to broad substrate specificity and redox potential. With advancement in biotechnology industry, fungi have been in use for commercial laccase production. Strain improvement is an essential part of process development for microbial products, to be economically feasible. It can reduce costs by developing strains with increased productivity. The strain improvement intended to increase production of desirable enzymes by mutant strains. Fungal strain improvement to increase production of enzymes has been the feature of all viable fermentation processes, such superior strains can be cost effective with better productivity. Present study, proposed the possibility for the exploitation of the Rigidoporus sp. DK4 and its mutants for production of laccase under SmF and SSF. So, present study was carried out to enhance the production of laccase by means of chemical and physical mutagens. newlineThe effects of various mutagens such as acrylamide, colchicines, ethylmethane sulphonate, ethidium bromide and gamma radiations on laccase production by Rigidoporus sp. DK4 were investigated. All chemical and physical mutagens have more distinct effect on its growth rate, higher concentration of mutagen may have lethal effect on treated fungi. All the mutagens showed varying influence on fungal growth. Screening of novel mutants was carried out using plate assay, based on guaiacol oxidation and polymeric dye decolourization. All mutants showed promising resluts in screening. In terms of laccase activity, no linear relationship observed with respect to concentrations of mutagens. Highest laccase producing mutant of Rigidoporus sp. DK4 (EMS treatment at 200and#956;g/ml) observed to produce 4.84 fold increase in laccase activity (34560U/L), therefore EMS-200 mutant strain was selected for further optimization study. newlineRigidoporus sp. DK4 cultivated under submerged fermentation condition to optimize culture conditions for induction of hyper laccase prod