Optimization of low-cost medium constituents for submerged fermentation of Ganoderma lucidum by using response surface methodology
响应曲面法优化灵芝廉价型深层发酵培养基的研究

To obtain a low-cost medium for submerged fermentation of Ganoderma lucidum in a large scale, four medium constituents were optimized by using central composite rotatable design (CCRD) and response surface methodology (RSM). The four factors were corn flour (x_1), wheat bran flour (x_2), soybean flour (x3) and sucrose (x_4). The results show that the mathematical model for biomass production and polysaccharide production are Y_1 = 15.1 - 0.31x_1 - 0.34x_2 + 0.36x_3 - 0.44x_4 - 1.26x_1~2 - 1.98x_2_2 - 0.85x_3~2 - 1.15x_4~2 - 0.59x_2x_3, and Y_2 = 2,0 - 0.08x_1 - 0.08x_2 + 0.04x_3 - 0.09x_4 - 1.13x_1~2 - 0.33x_2~2 - 0.08x_3~2 - 0.16x_4~2 - 0.16x_2x_3 - 0.10x_1x_4, respectively. Based on the models, the optimum medium for biomass production is corn flour 19.7g/L, wheat bran flour 11.3g/L, soybean flour 6.3g/L, and sucrose 19.5g/L; while the optimum medium for polysaccharide production is corn flour 19.6g/L, wheat bran flour 11.0g/L, soybean flour 6.7g/L, and sucrose 19.1g/L. The maximum biomass and polysaccharide in a 150-L stirred-tank bioreactor reach 16.92g/L and 1.86g/L under the optimized medium, respectively. The use of the medium can reduce the costs for both biomass and polysaccharide production by G. lucidum at large scale.