Significance of fungal elicitors on the production of ganoderic acid and Ganoderma polysaccharides by the submerged culture of medicinal mushroom Ganoderma lucidum

The main components of polysaccharide, protein and lipid (i.e., whole elicitor) and the sole polysaccharide component (i.e., polysaccharide elicitor) isolated from the cultured mycelia of Tuber aestivum vittad significantly stimulated the accumulation of extracellular polysaccharides (EPS), and the highest EPS production of 0.92 ± 0.07 g/L was obtained by the elicitation of its whole elicitor. The highest content (i.e., 12.91 ± 1.05 mg/100 mg) and production (i.e., 1.94 ± 0.18 g/L) of intracellular polysaccharides (IPS) was obtained by adding the combination components of polysaccharide and protein (i.e., elicitor of polysaccharide and protein) from Tuber sinense. Specific ganoderic acid (GA) biosynthesis (i.e., GA content) was stimulated by adding the elicitor of polysaccharide and protein, while inhibited by the polysaccharide elicitor prepared from Tuber melanosporum. While, the maximal GA production of 315.5 ± 12.4 mg/L was obtained under the elicitation of polysaccharide elicitor from Penicillium citrinum because of a relatively high cell density.