Appl Biochem Biotechnol. 2014 Jan;172(1):340-50. doi: 10.1007/s12010-013-0539-x.
Corynebacterium glutamicum wild type lacks the ability to utilize the xylose fractions of lignocellulosic hydrolysates. In the present work, we constructed a xylose metabolic pathway in C. glutamicum by heterologous expression of the xylA and xylB genes coming from Escherichia coli. Dilute-acid hydrolysates of corn cobs containing xylose and glucose were used as a substrate for succinic acid production by recombinant C. glutamicum NC-2. The results indicated that the available activated charcoal pretreatment in dilute-acid hydrolysates of corn cobs could be able to overcome the inhibitory effect in succinic acid production. Succinic acid was shown to be efficiently produced from corn cob hydrolysates (55 g l(-1) xylose and 4 g l(-1) glucose) under oxygen deprivation with addition of sodium carbonate. Succinic acid concentration reached 40.8 g l(-1) with a yield of 0.69 g g(-1) total sugars within 48 h. It was the first report of succinic acid production from corn cob hydrolysates by metabolically engineered C. glutamicum. This study suggested that dilute-acid hydrolysates of corn cobs may be an alternative substrate for the efficient production of succinic acid by C. glutamicum.
谷氨酸棒杆菌野生型缺乏利用木质纤维素水解物中木糖部分的能力。在本工作中，我们通过异源表达来自大肠杆菌的 xylA 和 xylB 基因，在谷氨酸棒杆菌中构建了木糖代谢途径。含有木糖和葡萄糖的玉米芯稀酸水解物被用作重组谷氨酸棒杆菌 NC-2 生产琥珀酸的底物。结果表明，可用的活性炭预处理可克服玉米芯稀酸水解物中对琥珀酸生产的抑制作用。在添加碳酸钠的缺氧条件下，从玉米芯水解物（55 g l(-1)木糖和 4 g l(-1)葡萄糖）中可有效地生产琥珀酸。在 48 小时内，琥珀酸浓度达到 40.8 g l(-1)，总糖得率为 0.69 g g(-1)。这是首次报道通过代谢工程改造的谷氨酸棒杆菌从玉米芯水解物中生产琥珀酸。本研究表明，玉米芯稀酸水解物可能是谷氨酸棒杆菌高效生产琥珀酸的替代底物。
