代谢木糖重组谷氨酸棒杆菌的构建

Construction of xylose-utilizing recombinant Corynebacterium glutamicum strain

为了使谷氨酸棒杆菌较好地利用木糖生产有机酸,将来自Escherichia coli K-12的木糖异构酶基因xylA构建到表达载体pXMJ19中,导入Corynebacterium glutamicum ATCC13032Δldh中,成功表达了该酶基因。结果表明:重组菌株在以木糖为唯一C源进行发酵时,木糖的消耗速率为0.54 g/(L·h),木糖异构酶比酶活约为0.54 U/mL;在以木糖和葡萄糖的混合糖为C源进行发酵时,菌株优先利用葡萄糖,在葡萄糖完全消耗后,菌株开始有效利用木糖;以木糖为唯一C源进行两阶段发酵时,琥珀酸的收率可达(0.62±0.003)g/g。

In order to construct a strain of Corynebacterium glutamicum by using the xylose to produce organic acids,the xylA gene from Escherichia coli K-12,encoding xylose isomerase,was integrated in the expression vector of pXMJ19.The gene was expressed in the Corynebacterium glutamicum ATCC13032Δldh strain.The recombinant strain was capable of growth on xylose as a sole carbon source,the xylose consumption rate was 0.54 g/（ L＆#183;h ）.The xylose isomerase activity reached 0.54 U/mL.In medium containing glucose and xylose, the recombinant strain consumed glucose first, after the glucose was consumped entirely, the effective utilization of xylose was started.The yield of succinate was （ 0.62 ＆#177; 0.003） g/g during the two-stage fermentation on xylose as a sole carbon source.