单 位：
江南大学生物工程学院工业生物技术教育部重点实验室
关键词：
L-异亮氨酸;化学诱变;常压室温等离子体;抗性筛选
摘 要：
旨在诱变选育L-异亮氨酸高产菌,并探索突变株最佳发酵条件。利用传统化学诱变结合常压室温等离子体生物诱变体系对实验室保藏的Brevibacterium flavum I-12进行逐级诱变,选育2-噻唑丙氨酸(2-TA)和磺胺胍(SG)高抗性和在琥珀酸平板上能快速生长的突变菌株。随后,在单因素实验的基础上,利用响应面设计优化出目的突变株摇瓶发酵培养基组分的最佳参数水平。结果显示,经过一系列诱变和筛选,成功选育出一株在40 g/L的2-TA和5 g/L的SG,且以琥珀酸为唯一碳源的培养基上快速生长突变株,命名为B. flavum TA-6,该菌株产酸达26.2±0.5 g/L,比出发菌株提高了44.75%,而副产物L-缬氨酸和L-亮氨酸积累量明显降低。经响应面法优化发酵条件后,突变株产酸可达27.8±0.5 g/L,比优化前提高了6.1%。通过传统化学诱变结合ARTP生物诱变体系,成功选育出一株杂酸降低的L-异亮氨酸高产菌TA-6,该菌株具有潜在生产应用价值。
译 名：
Breeding of Strain Producing L-isoleucine and Medium Optimization for It
作 者：
WANG Zhuang-zhuang;WEI Jia;YU Hai-bo;XU Jian-zhong;ZHANG Wei-guo;Key Laboratory of Industrial Biotechnology,Ministry of Education,School of Biotechnology,Jiangnan University;
单 位：
WANG Zhuang-zhuang%WEI Jia%YU Hai-bo%XU Jian-zhong%ZHANG Wei-guo%Key Laboratory of Industrial Biotechnology,Ministry of Education,School of Biotechnology,Jiangnan University
关键词：
L-isoleucine;;chemical mutagenesis;;atmospheric pressure room temperature plasma;;resistance screening
摘 要：
This work aims to breed a strain yielding high L-isoleucine by mutagenesis,and explore the optimal fermentation conditionsfor the mutant strain. The original strain Brevibacterium flavum I-12 was mutagenized by conventional chemical mutagenesis and atmosphericand room temperature plasma(ARTP)biological breeding system. A mutant strain having high resistance to 2-thiazolyl alanine(2-TA)andsulfaguanidine(SG)and capable of rapid growth on a succinic acid plate was selected. Subsequently,the response surface design based onthe single factor experiment was used to optimize the optimal parameter level of the shake flask fermentation medium components for the targetmutant strain. Results showed that a strain producing L-isoleucine was obtained after multiple rounds of random mutagenesis and screening,which was resistant to 40 g/L of 2-TA and 5 g/L of SG and rapidly grew on the medium with succinate as the sole carbon source,and designatedas B. flavum TA-6. The L-isoleucine production by this mutant strain reached 26.2±0.5 g/L,which was 44.75% higher than that by the originalstrain(18.1±0.5 g/L);while the accumulations of side product L-valine and L-leucine significantly reduced. The L-isoleucine productionincreased to 27.8±0.5 g/L after optimizing the fermentation conditions by response surface method,which was 6.1% higher than that beforeoptimization. In conclusion,a strain yielding high L-isoleucine but producing low other acids,TA-6,is obtained by conventional chemicalmutagenesis and ARTP biological breeding system,thus it has potential production and application value in L-isoleucine fermentation industry.
