Abstract:

The influence of fungal elicitors on the liquid fermentation of Ganoderma lucidum (Fr.) Karst was investigated. The fungal elicitors were prepared by acid hydrolysis of edible fungal pathogens including Trichoderma viride (Per.) Fries, Verticillium psalliotae Treschew, and Acremonium strictum Gams. These obtained elicitors were added to the fermentation media of G. lucidum at different concentrations and at different stages and. Addition of A. strictum elicitor at concentration of 120μg/ml to the fermentation media of G. lucidum at middle stage and initial stage resulted in 6.1 folds and 5.2 folds higher of yields of polysaccharide and triterpenoid, compared to the control. T. viride elicitor added at the concentration of 80μg/ml at late stage stimulated a moderate yields of the polysaccharide and triterpenoid whereas the V. psalliotae elicitor resulted in the lowest effect on the two kinds of bioactive products in G. lucidum among these elicitors. In addition, these tested fungal elicitors still enhanced the biomass yield, especially T. viride elictor at concentration of 80μg/ml, resulting in 2.3 folds higher of biomass yield than the control when added to the fermentation media of G. lucidum at initial stage. These results showed that effects of fungal elicitor could vary on the secondary metabolism of G. lucidum.

Key words: fungal pathogens, submerged fermentation, intracellular polysaccharide, intracellular triterpenoids, metabolism regulation