Enhanced polysaccharide production through quorum sensing system in Cordyceps militaris

Abstract

This study aimed to enhance extracellular polysaccharide (EPS) production in Cordyceps militaris by constructing a quorum sensing (QS) system to regulate the expression of biosynthetic enzyme genes, including phosphoglucomutase, hexokinase, phosphomannomutase, polysaccharide synthase, and UDP‐glucose 4‐epimerase genes. The study found higher EPS concentrations in seven recombinant strains compared to the wild‐type C. militaris, indicating that the overexpression of key enzyme genes increased EPS production. Among them, the CM‐pgm‐2 strain exhibited the highest EPS production, reaching a concentration of 3.82 ± 0.26 g/L, which was 1.52 times higher than the amount produced by the wild C. militaris strain. Additionally, the regulatory effects of aromatic amino acids on the QS system of the CM‐pgm‐2 strain were investigated. Under the influence of 45 mg/L tryptophan, the EPS production in CM‐pgm‐2 reached 4.75 ± 0.20 g/L, representing a 1.90‐fold increase compared to wild C. militaris strains. This study provided an effective method for the large‐scale production of EPSs in C. militaris, and opened up new avenues for research into fungal QS mechanisms.