Advances in biosynthesis of cordycepin from Cordyceps militaris / 生物工程学报

Cordycepin as the main active ingredient of Cordyceps militaris, a traditional medicinal fungus in China, has many physiological functions such as anti-cancer, anti-tumor and anti-virus activity. The most potential route for effective cordycepin production has been considered as liquid fermentation of C. militaris though with low productivity at present. Thus, it is urgent to apply both process engineering strategy and metabolic engineering strategy to enhance the productivity of cordycepin. In this review, the effects of medium components (i.e. the carbon/nitrogen source, precursor substances and metal ions) and operation factors (i.e. pH, dissolved oxygen and light) on cordycepin biosynthesis in liquid fermentation system are summarized. Besides, separation of cordycepin, the gene cluster involved and predicted biosynthesis pathways of cordycepin are also discussed, providing possible solutions of finally realizing efficient production of cordycepin.

Assessment of Palm Press Fibre and Sawdust-Based Substrate Formulas for Efficient Carpophore Production of Lentinus squarrosulus (Mont.) Singer

Development of efficient substrate formulas to improve yield and shorten production time is one of the prerequisites for commercial cultivation of edible mushrooms. In this study, fifteen substrate formulas consisting of varying ratios of palm press fibre (PPF), mahogany sawdust (MS), Gmelina sawdust, wheat bran (WB), and fixed proportions of 1% calcium carbonate (CaCO3) and 1% sucrose were assessed for efficient Lentinus squarrosulus production. Proximate compositions of mushrooms produced on the different substrate formulas were also analysed and compared. Substrate formulations containing 85% PPF, 13% WB, 1% CaCO3, and 1% sucrose were found to produce the highest carpophore yield, biological efficiency and size (206.5 g/kg, 61.96%, and 7.26 g, respectively). Days to production (first harvest) tended to increase with an increase in the amount of WB in the substrate formulas, except for PPF based formulas. The addition of WB in amounts equivalent to 8~18% in substrate formulas containing 80~90% PPF resulted in a decrease in the time to first harvest by an average of 17.7 days compared to 80~90% MS with similar treatment. Nutritional content of mushrooms was affected by the different substrate formulas. Protein content was high for mushrooms produced on formulas containing PPF as the basal substrate. Thus, formulas comprising PPF, WB, CaCO3, and sucrose at 85% : 13% : 1% : 1%) respectively could be explored as starter basal ingredients for efficient large scale production of L. squarrosulus.