灵芝胞外多糖高产菌株筛选及其深层发酵培养基的优化

Screening of Ganoderma lucidum Strains with High Extracellular Polysaccharide Productivity and the Optimization of Its Submerged Culture Medium

运用反馈抑制理论构建了耐灵芝胞外多糖 (EPS)反馈抑制的筛选模型。添加在筛选培养基中的其指示因子同源胞外多糖浓度为 2 .34g/L。将实验室保藏的 37株灵芝菌株输入该模型 ,即可检出耐灵芝胞外多糖反馈抑制作用最强、产胞外多糖能力最强的菌株GL0 2 9。然后在基础培养基的基础上用正交试验方法优化GL0 2 9深层发酵培养基。结果表明 ,组合碳源和组合氮源培养基最适合该菌株深层发酵生产灵芝胞外多糖。深层发酵培养基配方为 :蔗糖 10 g/L ,玉米粉15 g/L ,蛋白胨 2 g/L ,酵母膏 1g/L ,KCl 0 .5g/L ,KH2 PO4 ·7H2 O 0 .5 g/L ,pH自然。于 30℃、12 0r/min摇瓶培养 9d ,该菌株的胞外多糖产量高达 3.0 7g/L。

The theory of feedback inhibition was used to construct the screening model of Ganoderma lucidum extracellular polysaccharide (EPS) feedback inhibition resistant. And the concentration of its indicating factor, the homologous EPS added in the screening medium, was proved to be 2.34g/L. While GL029, the best G.lucidum EPS feedback inhibition resistant strain, namely the strain with the highest EPS productivity,was selected when 37 G. lucidum strains preserved in our laboratory were put into the screening model. Then the orthogonal test was used to optimize the submerged culture medium for GL029. The experimental results showed that the combined C sources and N sources were the optimum nutritional sources for the submerged culture of GL029 to produce EPS, and that 3.07g/L EPS could be produced when GL029 was cultured for 9d under the environment conditions of natural pH, 30℃ and with a rocking rate of 120r/min, by the medium of sucrose 10g/L, corn meal 15g/L, peptone 2g/L, yeast extract 1g/L, KCl 0.5g/L, KH 2PO 4·7H 2O 0.5 g/L and water 1000mL.