中文摘要：

木质纤维素生物质是一种由多种糖类组成的混合碳源,对于生产各种生物燃料和生物化学物质有很重要的经济意义和环境意义。因此,许多研究者致力于多种糖类共利用的研究。作者在研究中探讨了在好氧和厌氧条件下,调控crp基因（crp＋）对菌株消耗诸如葡萄糖、果糖、木糖等糖类组成的混合碳源的影响。野生型先消耗葡萄糖,葡萄糖耗尽后果糖和木糖才同时被消耗。在crp＋突变株中,分解代谢阻遏在一定程度上被解除,胞外木糖醇产量降低,使得果糖和木糖能够同时被消耗,木糖的消耗速率增加。同时,通过发酵数据、基因转录水平分析和代谢流分析等方法来阐明crp＋对整体调控机制的影响。crp基因的增强会导致c AMP-Crp的活性提高,从而促进TCA循环、抑制糖酵解途径,使乙酸的产量下降。

英文摘要：

Lignocellulosic biomass consisted with multiple sugar mixtures is thought to have great economic and environmental significance in producing various biofuels and biochemicals. The effects of modulating crp（crp＋） genes on multiple carbon sources consumption（such as glucose, fructose, and xylose） were investigated under both aerobic and anaerobic conditions. The results show that glucose was first consumed for the wild-type Escherichia coli, and fructose and xylose are followed upon glucose depletion. However, the catabolic repression of the crp＋ mutant was relaxed, and extracellular xylitol production was reduced, which leads to co-consumption of fructose and xylose and increased xylose consumption rates. Fermentation data, flux analysis, and gene transcript analysis were used to clarify how crp amplification affected overall regulation mechanisms. The amplification of crp improved intracellular c AMP-Crp activity, which activates TCA, restrains glycolysis and causes the decrease of acetate production.