The gene gltA coding citric acid synthase of an L-lencine producing strain Corynebacterium glutamicum ALDP was knocked out by homologous recombination, and the mutant citrate transporter coding gene CP_103 was introduced to obtain a strain capable of efficiently ingesting citric acid. On that basis, the effect of different citric acid adding methods on the OD600 nm value, L-leucine production and the conversion ratio of glucose to acid was investigated. The results showed that the citrate acid uptake capacity of C. glutamicum ALDPΔgltA was significantly increased by introducing mutant gene CP_103 coding citric acid transporter. When the initial citrate addition was 5 g/L and the citric acid content was maintained in the range of 10-15 g/L by feeding during fermentation process, the OD600 nm value of C. glutamicum ALDPΔgltACP_103 decreased slightly. However, the L-leucine production of C. glutamicum ALDPΔgltACP_103 was the highest and reached (22.5±1.5) g/L, and the conversion ratio of glucose to acid was 23.1％, which increased by 23.0％ and 48.1％, respectively, comparing with the original strain C. glutamicum ALDP.%该研究利用同源重组方法敲除L-亮氨酸生产菌株谷氨酸棒状杆菌(Corynebacterium glutamicum)ALDP的柠檬酸合酶基因gltA,并引入柠檬酸转运蛋白突变基因CP_103,获得一株能高效摄取柠檬酸的菌株.在此基础上,比较不同的柠檬酸添加方式对菌株的OD600nm值、L-亮氨酸产量和糖酸转化率的影响.结果表明,通过引入柠檬酸转运蛋白突变基因CP_103,显著提高了C. glutamicum ALDPΔgltA的柠檬酸摄取能力.当初始发酵液中的柠檬酸添加量为5 g/L,并在发酵过程中通过流加的方式维持柠檬酸含量在10～15 g/L范围内,较出发菌株C. glutamicum ALDP,C. glutamicum ALDPΔgltACP_103的OD600nm值轻微下降,但是L-亮氨酸产量达到最高,为(22.5±1.5)g/L、糖酸转化率为23.1％,分别提高23.0％和48.1％.
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