Response Mechanism of Extracellular Laccase Activity of Lyophyllum decastes to Cultivation Substrates and Subculture

Abstract

Different fermentation substrates were employed to investigate the variation patterns of lignocellulolytic enzymes in Lyophyllum decastes and the changes in laccase activity in subculture. The results showed that the activities of Lac, CMCase, and Xyl produced by the L. decastes F1 strain in liquid fermentation were significantly affected by different cultivating substrates. The optimal primary substrate for inducing Lac secretion in L. decastes F1 strain was corncob, followed by cottonseed hulls. The best supplementary substrate for Lac induction was soybean meal. The addition of corn cob and wheat bran was found to significantly stimulate the secretion of CMCae and Xyl in L. decastes F1 strain. The addition of different cultivation substrates enhanced Lac production in L. decastes subcultured strains (F1, F5, F10), but strains subjected to serial subculturing exhibited progressively diminished laccase production. The highest laccase activity detected in the fastest-growing subcultured strains within identical solid cultivation substrates demonstrated a phase-specific positive correlation between mycelial growth and extracellular laccase secretion.