Statistical Optimization of Polysaccharides Production by the Lingzhi or Reishi Medicinal Mushroom Ganoderma lucidum (Agaricomycetes) in Solid-State Fermentation Using Highland Barley Grains.

Ganoderma lucidum is a widely used medicinal mushroom in traditional Chinese medicine that creates a diverse set of bioactive compounds. Highland barley, a typical nutrition-balanced crop, is not convenient for direct consumption but its nutritional characteristics meet the modern requirements of health food. In the present study, barley grains were used as substrates on solid-state fermentation (SSF) of G. lucidum. Statistical optimization of media composition was employed for enhancing the production of polysaccharides. Peptone, medlar, and KH2PO4 were identified as the most important components for producing polysaccharide. Based on the one-factor-at-a-time experimentation, a quadratic regression model with the polysaccharide contents as the response value was established by central composite design (CCD). The results showed that the predicted variables were 2.38% peptone, 1.14% medlar, and 0.25% KH2PO4 for the maximum yield of predicted polysaccharides of 11.64% in the fermented substrate. The experimental polysaccharides obtained using the predicted optimum media composition constituted 11.61% of the fermented substrate, which validates the high degree of accuracy of optimization for enhanced production of polysaccharides by SSF. This study suggested that in the process of barley grains fermentation by G. lucidum for polysaccharides production, the optimized SSF substrate consists of 71.4% barley grains, 2.38% peptone, 1.14% medlar, 0.25% KH2PO4, 2.5% glucose, 0.25% MgSO4 · 7H2O, and 1% CaCO3. According to this study, the strain G. lucidum 00679 showed a good fermentation property by optimizing the media. It might be a candidate industrial strain for further process optimization and scale-up study.

Cloning of mating-type gene MAT1-1 from the caterpillar medicinal mushroom, Cordyceps militaris (Ascomycetes) using TAIL-PCR technology.

Cordyceps militaris and Ophiocordyceps sinensis (syn. Cordyceps sinensis), 2 well-known traditional Chinese medicines, contain the same bioactive components and share a similar developmental process. In this study, one C. militaris strain preserved in our laboratory was proven to be a MAT1 mating-type strain using a polymerase chain reaction-based mating-type assay. A 5000-bp nucleotide sequence of the mating-type MAT1-1 from C. militaris was amplified by thermal asymmetric interlaced polymerase chain reaction, but genes within the mating-type MAT1-2 remain undetectable. Sequence analysis shows that the mating-type gene MAT1-1 idiomorph contains 2 genes, MAT1-1-1 and MAT1-1-2. The MAT1-1-1 gene consists of 1480-bp nucleotides that encode 456 amino acids and contain the conserved a-box domain interrupted by 2 introns; the MAT1-1-2 gene consists of 1066 nucleotides that encode 377 amino acids interrupted by one intron. The intervening distance between MAT1-1-1 and MAT1-1-2 is 778 bp. The C. militaris MAT1-1 idiomorph organization is the same as that of Cordyceps takaomontana. The MAT1-1 mating-type idiomorph of both Cordyceps species lacks the MAT1-1-3 gene, which is typically present in Pyrenomycetes. These studies provide some insights for further study of the morphological development of C. militaris and will eventually benefit the domestication of O. sinensis.