Study on the effect of Siraitia grosvernori fruit extracts on polysaccharides production of Ganoderma lucidum

Abstract

Ganoderma lucidum is a polypore mushroom of which polysaccharides have been reported to have numerous biological activities (antioxidant, antidiabetic, anti- LQÀDPPDWLRQ DQG DQWL-tumor activities). The purposes of this study were to study the effect of Siraitia grosvernorii fruit on the growth and polysaccharide (PS) production of G. lucidum and to optimize the PS production of this fungus by using Response Surface Methodology (RSM). The obtained results revealed that adding S. grosvernori fruit either in the form of fruit powder or fruit extracts had no significant effect on dry cell weight (DCW) of G. lucidum. However, adding the fruit powder significantly increased the PS production. Three variables including fruit powder, glucose concentration and yeast extract were selected for RSM study. 15 treatments were designed using Box-Behnken method and JMP 9 software. The statistical analysis showed that these three variables had significant effects on PS production and they interacted with each other (F < 0.05). Glucose and fruit powder was found to have positive effect as increasing their concentrations led to the increase of PS production. However, the interaction was saturated when the fruit powder was at concentration of 3 g/l. Glucose and yeast extract showed a negative interaction as raising the concentrations of them at the same time resulted in lower polysaccharide production. The maximum PS production (5 g/l) was found from the treatment of which the medium compositions included: 2 (g/l) fruit powder, 30 (g/l) glucose and 2 (g/l) yeast extract. Under these conditions, PS production of G. lucidum was enhanced 1.67 times compared with the original culture (3.0025 g/l) Key words: Ganoderma lucidum, polysaccharides, optimization, RSM, Siraitia grosivenorii,