Experimental analysis on the effect of addition of <i>Rhizoma gastrodiae</i> on mycelia and exopolysaccharide productions by submerged culture of <i>Grifola frondosa</i>

Abstract

The effect of addition of Rhizoma gastrodiae on mycelia and exopolysaccharide production by submerged culture of Grifola frondosa was investigated. About 7% (v/v) of R. gastrodiae extract was added to the basal medium used for its biomass and exopolysaccharide productions. The biomass and exopolysaccharide productions reached a maximum of 2.0630±0.0520 g/L and 89.3846±3.2422 mg/L, respectively after day 10 and 8 of cultivation. G. frondosa was sensitive to R. gastrodiae, and there was a reduction in the cycle of exopolysaccharide synthesis. The pH variation in culture provided an indirect inference to this stimulating effect of R. gastrodiae extract addition. Moreover, a curve fitting and parameter analysis was carried out to assay the increasing effect on biomass and exopolysaccharide productions. Meanwhile, the kinetics parameters predicted through the fitting equations in culture, X0 = 0.1523 g/L, Xm = 2.0630 g/L, µm = 0.4994 d-1, α = 0.0858 and α = -0.0069, further clarified the stimulatory effects of R. gastrodiae extract addition in G. frondosa culture.

Key words: Rhizoma gastrodiae, Grifola frondosa, biomass, exopolysaccharide.