【作者】 张慧；

【导师】 陈宁；

【作者基本信息】 天津科技大学 ， 轻工技术与工程， 2005， 硕士

【摘要】 本文以代谢控制发酵理论为指导,重点研究了L-缬氨酸高产菌的选育及其发酵条件。主要研究内容和结果如下: (1)确定了黄色短杆菌TV826与黄色短杆菌TV1053原生质体融合的最佳条件,以黄色短杆菌(Brevibacterium flavum)TV1053和黄色短杆菌(B.flavum)TV826为亲株,采用原生质体融合技术,定向选育出了具有目的遗传标记的86株融合子,经过对这些融合子进行初筛和复筛,最终得到一株在摇瓶发酵条件下,L-缬氨酸产量达到26g/L的目的融合子TV02256。将目的融合子TV02256连续传代,结果表明该融合子TV02256的遗传是稳定的。 (2)对选育获得的L-缬氨酸高产菌株进行摇瓶分批发酵试验,运用正交设计试验法和主成分分析法优化出最佳种子培养基和发酵培养基组成,并确定了最优发酵培养条件。在最优条件下,目的融合子TV02256摇瓶分批发酵L-缬氨酸产量达到39.4g/L。 (3)以摇瓶分批发酵最优条件为基础,进行200吨发酵罐分批发酵放大试验,确定了最佳分批发酵工艺,6批次的L-缬氨酸平均产酸达43.8g/L,糖酸转化率平均为25.6%。更多还原

【Abstract】 According to the theory of metabolic control fermentation, the dissertation focuses on the breeding and fermentation condition of L-valine high-yielding strain. The main research contents and results are as follows:(1) The optimum conditions of protoplast fusion of Brevibacterium flavum TV1053 and Brevibacterium flavum TV826 were dermined. 86 fusion hybrids were got by the method of protoplast fusion with Brebibacterium flavum TV1053 and Brebibacterium flavum TV826 as the parent strains. Finally one L-valine high-producing TV02256 was screened. The strain could produce L-valine 26g/L under the fermentation condition without being optimized. Genetic character of Strain TV02256 was very stable.(2) The batch fermentation condition of the L-valine high-producing strain in shake flask was studied in this dissertation. The seed medium was optimized by orthogonal design experiment,and the seed culture conditions were also studied. The fermentation medium was optimized by the method of principal component analysis and fermentation conditions were studies. Under the optimum condition, the strain TV02256 could produce L-valine 39.4g/L by shaking flask batch fermentation.(3) Based on the above optimum condition, the batch fermentation was performed in 20000-liter fermentor. And the optimal fermentation conditions were got.更多还原