Optimization of Ganoderma leucocontextum Fermented Tea Medium Formula Based on High-yield Extracellular Crude

To investigate the optimal nutritional conditions and their contributing factors for the secretion of extracellular crude polysaccharides with Ganoderma leucocontextum on a liquid tea substrate, this study optimized the nutritional conditions of its extracellular crude polysaccharides formation by orthogonal experiment and analysis of variance on the basis of the single-factor test, and explored the relevance between its liquid culture characteristics and the secretion of extracellular crude polysaccharides using correlation and path analyses. The results of study revealed that the greatest output of extracellular crude polysaccharide (1.49±0.33 g/L) was achieved on a tea culture medium of 50 g/L potato, 40 g/L glucose, 3 g/L laterite, 20 g/L Pu'er tea and 0.075 mm tea powder particle size, and was affected by each nutritional condition in the descending order of glucose>tea variety>laterite>potato>tea powder particle size. Moreover, the secretion of extracellular crude polysaccharides in G. leucocontextum was significantly impacted by the soluble solids of the fermentation broth and the number of mycelium balls, with the former having the greatest indirect effect while the latter, the greatest direct and combined effect on it. In conclusion, the nutritional conditions (variety, concentration, particle size, etc.) of the tea culture medium and the liquid culture characteristics of G. leucocontextum exerted a significant and interactive effect on the secretion of extracellular crude polysaccharides, and the aforesaid results may provide a theoretical reference for extraction of polysaccharides from this mushroom and development of it as functional foods.