Influence of carbon, nitrogen sources, inducers, and substrates on lignocellulolytic enzyme activities of Morchella spongiola

Abstract

The influence of various carbon, nitrogen sources, inducers, and different agro-wastes on the growth and ligninolytic enzyme activities of Morchella spongiola (MR17) was studied. This fungus has grown well in mineral salts broth containing mannitol as the carbon and yeast extract as the nitrogen sources. In presence of inducers, the growth was inhibited compared to control. The carbon and nitrogen sources and the inducers affected the laccase activity of M. spongiola . Rhamnose and galactose supported the laccase activity more than other carbon sources tested. The manganese peroxidase (MnP) and versatile peroxidase (VP) activities were not detected in the medium amended with different carbon and nitrogen sources. The inducers, ABTS, and veratryl alcohol enhanced the laccase activity more than others. The MnP activity was maximum in wheat straw, followed by rice straw and phenol red. Maximum VP activity was observed in wheat straw, and rice straw, followed by veratryl alcohol. The protein content increased significantly in groundnuts shell and wheat grain substrates inoculated with M. spongiola . Wheat grains and wheat bran served as the most promising substrates with maximum lignocellulolytic activity. The laccase activity was higher in wheat grains and wheat bran, while VP and MnP activities were higher in rice straw and wheat straw. The cellulase activity was much less compared to other enzyme activities in all the substrates. Maximum lignin degradation was observed in wheat straw, followed by wheat bran. The cellulose degradation was significantly higher in groundnuts shell compared to other substrates. The present study results suggest that M. spongiola can utilize these substrates, induce enzyme activities, and have the potential for mushroom cultivation.