为提高乙醇产率,通过同源重组的方式敲除嗜热厌氧杆菌乳酸支路中的乳酸脱氢酶基因,得到了嗜热厌氧代谢工程菌Δldh突变株.应用葡萄糖、木糖、葡萄糖/木糖混合糖3种碳源,分别对Δldh突变株与野生菌进行分批补料发酵产乙醇的研究.结果表明,与野生菌相比,Δldh突变株不仅显著提高了乙醇产率,而且提高了糖的消耗速率;Δldh突变株与野生菌都能以葡萄糖和木糖为基质生长,而与木糖为单一碳源相比,在葡萄糖/木糖共发酵时,木糖消耗速率有所降低;在以葡萄糖为单一碳源时,Δldh突变株的乙醇质量浓度和产率达到最高,分别为25.93 g/L和0.39 g/（L.h）.

In order to improve the yield of ethanol,the lactate dehydrogenase in a key branch of Thermoanaerobacterium aotearoense was deleted via the homologous recombination,and the thermophilic and anaerobic metabolic engineered Thermoanaerobacterium aotearoense,namely Δldh mutant was screened.Then,glucose fermentation,xylose fermentation and glucose/xylose co-fermentation of Δldh mutant and the wild strain were respectively performed to produce ethanol.The results indicate that（1） as compared with the wild strain,Δldh mutant is of higher ethanol yield and rapid suger consumption;（2） both the Δldh mutant and the wild strain grow well on glucose and xylose;（3） as compared with sole xylose fermentation,a xylose restraining may occur during the glucose/xylose co-fermentation;and（4） when glucose is used as the sole carbon source,both the mass concentration and the yield of ethanol reach the maximum values,namely 25.93g/L and 0.39g/（L·h）,respectively.