苯甲酰胺和羧甲基纤维素钠对香菇菌丝体多糖合成和抗氧化活性的影响

Lentinula edodes polysaccharides exhibit diverse biological activities. Currently, most L. edodes polysaccharides are extracted from fruiting bodies, resulting in low yield, high cost, and short harvest period. Therefore, enhancing polysaccharide production has become a research priority. Epigenetic modifications regulate the synthesis and metabolism of secondary metabolites through various mechanisms and play significant roles in microbial secondary metabolism. To investigate whether polysaccharide synthesis in L. edodes is influenced by epigenetics, this study utilized L. edodes strain Xin 808 as experimental material, and analyzed the effects of different concentrations of two epigenetic modifiers [benzamide and sodium carboxymethyl cellulose (CMC-Na)] on mycelial growth, cellulase activity, polysaccharide production, activity of key polysaccharide-synthesizing enzymes, relative expression levels of the enzyme encoding genes, and antioxidant activity of polysaccharides. Results showed that although 4 µg/mL benzamid and CMC-Na reduced biomass compared to the control, they significantly promoted the growth of L. edodes mycelium on solid culture medium and increased the polysaccharide content in the mycelium. Cellulase activity decreased compared to that of the control, but the intracellular crude polysaccharide concentration increased, reaching 2.31-fold (benzamide) and 2.01-fold (CMC-Na) as compared with that of the control. The activities of UDP-glucose pyrophosphorylase (UGPase), phosphoglucose isomerase (PGI), and α-phosphoglucomutase (α-PGM), the enzymes associated with lentinan metabolism, increased. Under benzamide treatment, these enzymes exhibited increases in activity, increasing by 2.21-fold, 2.38-fold, and 2.19-fold as compared with enzyme activities of the control group, respectively. However, the relative expression levels of the encoding genes were significantly downregulated. In vitro polysaccharide antioxidant capacity increased in variant degrees. At the concentration of 0.2 mg/mL ·OH scavenging ability showed the most pronounced. These results demonstrate that adding benzamide and sodium carboxymethyl cellulose at appropriate concentrations influences L. edodes mycelial growth and polysaccharide synthesis.