Cordycepin production by a novel endophytic fungus Irpex lacteus CHG05 isolated from Cordyceps hawkesii Gray.

Cordycepin is an essential nucleoside antibiotic with a broad spectrum of physiological functions, which is currently produced by the fermentation of Cordyceps militaris. Even though numerous efforts were made to enhance cordycepin production, the cordycepin yield is still limited. High-cordycepin-yielding strains are still a prerequisite for industrial cordycepin production in large amounts. Screening high-cordycepin-yielding strains from other sources may break new grounds for cordycepin. In this study, Cordyceps hawkesii Gray, with high homology to C. militaris, was selected as the source to screen the cordycepin manufacturing endophytic fungi. Four isolates capable of cordycepin production were successfully obtained among all isolated endophytic fungi. One of the four with better cordycepin yield was identified as Irpex lacteus CHG05, which belongs to the Phlebia species. The response surface methodology was applied to optimize the culture conditions for cordycepin fermentation. 162.05 mg/L of cordycepin with a 53.1% improvement was achieved compared to the original conditions. This study indicates that the endophytic fungi from C. hawkesii Gray could produce cordycepin and served as the first report for cordycepin by the white-rot fungus of I. lacteus. Even though the yield is low compared to C. militaris, this strain provided another choice for enhanced cordycepin in the future.