食品与发酵工业2017，Vol.43Issue(10)：30-35,6.DOI:10.13995/j.cnki.11-1802/ts.014845
过表达mqo对重组谷氨酸棒杆菌L-异亮氨酸和4-羟基异亮氨酸合成的影响
Effects of mqo overexpression on the synthesis of L-isoleucine and 4-hydroxyisoleucine in recombinant Corynebacterium glutamicum
摘要
Abstract
4-hydroxyisoleucine (4-HIL),which can exhibit unique insulinotropic and insulin-sensitizing activities,has potential medical value in treating diabetes.An L-isoleucine (Ile)-producer,Corynebacterium glutamicum ssp.lactofermentum SN01 can synthesize 4-HIL when ido gene.In order to promote the supply of oxaloacetate and synthesis of 4-HIL,mqo was overexpressed in this recombinant strain.After 144 h of fermentation,4-HIL production of ido-mqo-expressing strain was (60.86 ± 2.24) mol/L,lower than that of ido-expressing strain (72.06 ± 5.60) mmol/L.However,its Ile concentration was (101.39 ± 2.20) mmol/L,significantly higher than that of ido-expressing strain (5.00 ± 1.43) mmol/L.The RT-PCR analysis of some key genes in the metabolic pathway of ido-mqo-expressing strain showed that the carbon flow entering the TCA cycle was diverted by the isocitrate lyase to the glyoxylic acid cycle,resulting in the insufficient supply of another substrate for 4-HIL synthesis,i.e.α-ketoglutarate (α-KG) and excessive Ile concentration.Therefore,ot-KG was added.When 40 mmol/L of o-KG was added,the yield of 4-HIL increased to (77.7 ± 10.91) mmol/L and the conversion ratio of Ile to 4-HIL increased to 75％.Therefore,overexpression of mqo can promote Ile synthesis,and addition of α-KG can promote the conversion of Ile to 4-HIL,thereby increasing the yield of 4-HIL.关键词
4-羟基异亮氨酸/谷氨酸棒杆菌SN01/L-异亮氨酸/mqo/α-酮戊二酸Key words
4-hydroxyisoleucine/Corynebacterium glutamicum ssp.lactofermentum SN01/L-isoleucine/mqo/α-ketoglutarate引用本文复制引用
卢正珂,史锋..过表达mqo对重组谷氨酸棒杆菌L-异亮氨酸和4-羟基异亮氨酸合成的影响[J].食品与发酵工业,2017,43(10):30-35,6.基金项目
江南大学食品科学与技术国家重点实验室自由探索资助课题(编号SKLF-ZZB-201405) （编号SKLF-ZZB-201405）
