Invesigation On Enzymatic Activities In Different Flammulina Strains

Lignocellulosic biomass is composed of three major components:lignin, cellulose and hemicellulose. The source of lignocellulosic biomass is extensive, and lignocellulosic biomass have renewable characteristic. Carbon and nitrogen sources are the most important nutrition for growth of edible fungi. The enzyme activities obtained from Flammulina strains were affected by carbon or nitrogen sources (including simple carbon or nitrogen sources and lignocellulose), fermentation method, ions and strains.Three Flammulina velutipes strains were used to study the effects of corncob and cottonseed hull as well as simple carbon and nitrogen sources on enzyme activities of cellulose, hemicellulose and lignin decomposition. The activities of CMCase, xylanase and laccase indicated significant differences among Flammulina velutipes strains (P<0.001), and cultural media significantly affected the activities of CMCase, xylanase and laccase in Flammulina velutipes (P<0.001). The CMCase and xylanase activities on medium with simple carbon sources were significantly reduced than those on medium with complicated carbon sources only. The CMCase and xylanase activities on complete yeast medium were significantly decreased than those on media without glucose (P<0.05) or simple nitrogen sources (P<0.05). The laccase activities on media without simple nitrogen sources were significantly lower than those on complete yeast media (P<0.05) and media without glucose (P<0.05), indicating the laccase activities on complicated media were lower than those media with simple carbon and nitrogen sources.Thirteen Flammulina strains were used to study the laccase activities in submerged fermentation using cottonseed hull as inducer. The results showed that the laccase activities varied significantly in different strains or cultural medium. The laccase activities of Flammulina were affected by the genetic distance and cultural conditions. In terms of species, the occurrence time of laccase activities by F. rossica isolates were earlier than that by F. velutipes and F.fennae. Generally, Cu2+ ion and complicated lignocellulose increased the secretion of extracellular enzymes. The effects of Cu2+ ion on laccase activities by different strains depended on the copper ion concentration which the strains could be tolerant. The copper ion concentration used in this study increased laccase activities by most stains, but decreased laccase activities by the strains of CCMSSC 05331 and BJFC 012295. Besides, appropriate concentration of simple carbon or nitrogen sources could increase laccase activities, and the occurrence time of laccase activities and maximum laccase activities were delayed comparing with complicated lignocellulose.