Construction of Cordycepin High-Production Strain and Optimization of Culture Conditions

This study aimed to increase cordycepin production by over-expressing bio-synthetic enzyme genes, including the adenylosuccinate synthase, adenylosuccinate lyase, and 5'-nucleotidase genes. Research data showed that the extracellular and intracellular cordycepin concent of 24 recombinant strains were higher than those of C. militaris WT, indicating that over-expression of key enzyme genes increased cordycepin production. Among them, the CM-adss-5 strain had highest cordycepin production, and the extracellular and intracellular cordycepin concent were 1119.75 ± 1.61 and 65.56 ± 0.97 mg/L, which were 1.26 and 2.61 times that of C. militaris WT. This study also optimized the culture conditions of CM-adss-5 strain through single factor experiments to obtain the best culture conditions. The best culture condition was 25 °C constant temperature, 180-rpm shaking culture, fermentation period 12 days, inoculate amount 5%, initial pH 6, seed age 108 h, and liquid volume 110/250 mL. Then, the extracellular and intracellular cordycepin content of CM-adss-5 strain reached 2581.96 ± 21.07 and 164.08 ± 1.44 mg/L, which were higher by 130.6% and 150.3%, respectively. Therefore, our research provides a way to efficiently produce cordycepin for the development of cordycepin and its downstream products.