聚γ-谷氨酸高产菌的选育与培养基优化

Screening of Poly-γ-glutamic Acid High Productive Strain and Optimization of Fermentation Medium

摘要:

利用合成培养基为筛选培养基, 以枯草芽孢杆菌(Bacillus subtilis) B6-1为出发菌株, 经过三轮紫外线诱变和一轮硫酸二乙酯诱变得到了聚γ-谷氨酸高产突变株枯草芽孢杆菌W003, 摇瓶液体发酵的聚γ-谷氨酸产量由出发菌株的10.9 g/L提高到20.5 g/L。单因素实验结果表明, 该菌产聚γ-谷氨酸的合适碳源为葡萄糖, 氮源为硫酸铵。通过正交实验得到了优化的培养基配方, 经36 h液体发酵, 聚γ-谷氨酸产量可达到45.3 g/L。

Abstract:

Bacillus subtilis B6-1 was used as an original strain for mutagenic treatment and a defined medium was used as the selective medium. A mutant named B. subtilis W003 was isolated after three serial ultraviolet (UV) irradiations and one diethyl sulfate (DES) treatment. The γ-PGA yield on a rotary shaker was enhanced from 10.9 g/L in parental strain to 20.5 g/L in the mutant. It was illustrated by single factor experiments that the optimal carbon and nitrogen sources were glucose and (NH4)2SO4 respectively. The optimal fermentation medium was achieved by orthogonal test. In the optimal medium, a γ-PGA yield of 45.3 g/L was obtained after 36 h cultivation.