Abstract:In the microbial screening of medicinal fungi with high ergothioneine（EGT） production，the existing EGT assay method requires improvement due to its cumbersome steps and the high cost of reagents and equipment. Transformants harboring the ergothionase plasmid （pET28a） were employed for heterologous expression to yield a crude ergothionase solution（ enzyme activity was 458.6 U/mL）. The rapid detection system of the enzymatic method was optimized using EGT standards and medicinal fungi as samples，and a correlation analysis was conducted between the results of the enzymatic method-based rapid detection and those of highperformance liquid chromatography （HPLC） to validate the practical feasibility of the enzymatic method for rapid detection of medicinal fungi. The results indicated that when 100 μL of sample solution was mixed with 100 μL of crude enzyme solution （45.86 U），and the absorbance of the reaction mixture was monitored at 311 nm for more than 20 min，the EGT content across samples could be detected rapidly and accurately.