The effect of alkali lignin on laccase activity and mycelial biomass of Flammulina velutipes: Alkali lignin on laccase activity and mycelial biomass

The effect of alkali lignin on laccase activity and mycelial biomass of Flammulina velutipes was investigated at different fermentation temperatures. The secretion of laccase by F. velutipes has certain specificity. Under most fermentation medium conditions, no laccase activity of F. velutipes CCMSSC 00103 was detected, but laccase activity of F. velutipes FL 19 could be detected. Among the three strains of F. velutipes, the laccase secretion capacity of F. velutipes FL 19 was clearly higher than that of F. velutipes CCMSSC 05331 and F. velutipes CCMSSC 00103. Maximum laccase activity with the value of 73.42 ± 4.74 U/L was secreted by F. velutipes FL 19 in fermentation medium with alkali lignin, KH2PO4, Vitamin B1, and glucose, and appeared on the 2nd day. The presence of alkali lignin was useful for improving laccase activity secreted by F. velutipes. The effect of alkali lignin on improving laccase activity exceeded that of Populus beijingensis. F. velutipes was more suitable for secreting laccase at 26 °C because the maximum laccase activity at 26 °C (73.42 ± 4.74 U/L) was higher than that measured at 33 °C (70.71 ± 6.89 U/L). The results can be useful for selecting suitable medium and temperature of F. velutipes strains to produce low-cost laccase.