摘要
L-异亮氨酸是多数哺乳动物必需氨基酸,广泛应用在食品、医药、运动营养等领域。为促进细胞内L-异亮氨酸外排,提高发酵液中L-异亮氨酸含量,以谷氨酸棒杆菌(Corynebacterium glutamicum)IBCL-1为出发菌株,构建CI01、CI02、CI03与IBCL-1ΔlysA 4株菌株。通过发酵对比CI01、CI02、CI03菌株生产L-异亮氨酸能力,其中CI01菌株L-异亮氨酸产量最高为21.36 g·L^(-1),相较于出发菌株IBCL-1提高6.8%。为降低主要副产物L-赖氨酸含量,敲除合成IBCL-1中L-赖氨酸关键基因lysA,所获菌株IBCL-1ΔlysA可大量消耗外源L-赖氨酸。最后将CI01与IBCL-1ΔlysA菌株混合发酵生产L-异亮氨酸,确定13:1为两种菌接种量最佳配比,发酵液中L-异亮氨酸含量为22.96 g·L^(-1),L-赖氨酸含量为0.42 g·L^(-1),显著提高L-异亮氨酸生产效率。
L-isoleucine is an essential amino acid for most mammals and is widely used in the fields of food,medicine and sports nutrition.In order to promote the efflux of L-isoleucine in cells and increase the content of L-isoleucine in the fermentation broth,Corynebacterium glutamicum IBCL-1 was used as the starting strain to construct strains CI01,CI02,CI03,and IBCL-1ΔlysA.By compared the production of L-isoleucine by CI01,CI02 and CI03 strains through fermentation,it was found that the Lisoleucine yield CI01 was the highest at 21.36 g·L^(-1),which was 6.8%higher than that of the starting strain IBCL-1.To reduce the content of the main by-product L-lysine,the key gene lysA for L-lysine synthesis in IBCL-1 was knocked out,and the obtained strain IBCL-1ΔlysA could consume a large amount of exogenous L-lysine.Finally,CI01 and the IBCL-1ΔlysA strain were mixed for fermentative production of L-isoleucine.The optimal ratio of inoculation of the two strains was determined to be 13:1.The final fermentation broth contained 22.96 g·L^(-1) of L-isoleucine and 0.42 g·L^(-1) of L-lysine and significantly improved the production efficiency of L-isoleucine.
作者
苏沣
洪皓
齐佳琨
刘军
范超
张春枝
SU Feng;HONG Hao;QI Jiakun;LIU Jun;FAN Chao;ZHANG Chunzhi(College of Biotechnology,Dalian Polytechnic University,Dalian Liaoning 116033,China;Dalian Yinuo Biological Co.,Ltd.,Dalian Liaoning 116600,China)
出处
《东北农业大学学报》
CAS
CSCD
北大核心
2023年第12期32-40,共9页
Journal of Northeast Agricultural University
基金
2021年辽宁省中央引导地方科技发展资金计划(2021JH6/10500223)。
