摘要
从发酵制品中分离到一株不依赖谷氨酸作为发酵底物的高产菌株PGA-N,通过形态、生理生化试验和遗传学研究,确定PGA-N为地衣芽胞杆菌(Bacillus licheniformis)。根据该菌株的产生环境,设计了无L-谷氨酸发酵基础培养基,并对该培养基进行了碳氮源优化和菌种诱变筛选。PGA-N经过亚硝基胍和紫外线诱变筛选后得一突变株——PGA-N-C10,其γ-PGA的产量提高到8.82g/L。实验还考察了搅拌转速与细胞生物量、γ-PGA产量以及γ-PGA分子量之间的关系,在搅拌速度为400r/min时,γ-PGA产率可高达11.00g/L。
A high productive poly γ-glutamic acid （γ-PGA） strain PGA-N in a culture medium containing no L-glutamine was isolated from fermentation products. With the following identifications of colony morphology, physiological and biochemistry experiments, and genetics, the strain PGA-N was classified as a Bacillus licheniformis. According to the product environment, the base culture medium having no L-glutamine was simulated. In order to enhance the production of the strain PGA-N, the fermentation conditions, such as carbon source, nitrogen source, were optimized and the γ-glutamic acid production reached 5.16 g/L after getting the optimum formulation of this culture medium. PGA-N was mutagenized with combination of NTG and UV. A mutant PGA-N-C10 was screened which PGA production was increased from 5.16 g/L to 8.82 g/L. The study also investigated the effects of agitation speed on the cell biomass, γ-PGA production and the γ-PGA molecular weight. The γ-PGA yield of PGA-N-C10 was as high as 11.00 g/L when the agitation speed was 400 r/min.
出处
《微生物学通报》
CAS
CSCD
北大核心
2009年第5期705-710,共6页
Microbiology China
基金
科技部科技计划项目(No.2008GB2E000233)
广州市科技计划项目资助(No.2006Z3-D0291)
越秀区科技计划项目(No.2007-PT-011)
