Abstract:

Effects of fermentation temperature and initial pH on the mycelial biomass and exopolysaccharides of Ganoderm lucidum GL0811 in flask culture were studied, and in the following batch fermentation, effects of pH and dissolved oxygen control during the fermentation process on the mycelial biomass and exopolysaccharides of Ganoderm lucidum GL0811 were further studied. The optimum flask culture conditions were as follows: temperature 30℃, initial pH 6.0. The strategy of pH and dissolved oxygen control were as follows: pH 5.5 druing 0－40h, pH 5.0 during 40－48h and pH 4.5 during 48－96h with the agitation rate 160 r/min and aeration rate 0.75vvm. Under the optimum condition, the maximum mycelial biomass and exopolysaccharides reached up to 19.7 g/L and 3.23g/L respectively, which were 53.9% and 35.1% higher than those in the uncontrolled fermentation.

Key words: Ganoderma polysaccharides, submerged fermentation, pH, dissolved oxygen, condition optimization