Fang Zhi-guo
College of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China.
Huan Jing Ke Xue. 2010 Apr;31(4):1059-65.
Fermentation of the type of cellulosic materials to ethanol was evaluated in batch system of mono-cultures of cellulolytic ethanol producing strains (Clostridium thermocellum strain LQRI), and co-cultures of LQRI in combination with one of the non-cellulolytic ethanol producing strains (Thermoanaerobacter pseudoethanolicus strains X514 or Thermoanaerobacter ethanolicus 39E). Results showed that ethanol yields and cellulose degradation abilities were significantly improved by the establishment of co-cultures consisting of LQRI and Thermoanaerobacter ethanolicus partner. A factorial experimental comparison revealed that the co-culture of LQRI + X514 provided the higher ethanol yield than the co-culture of LQRI + 39E, but no significant difference on cellulose degradation by LQRI was found in these co-cultures. In the absence of yeast extract, the highest ethanol concentrations in the co-cultures of LQRI + X514 and LQRI + 39E were about 71 mmol/L and 36.5 mmol/L, which were approximately 5-11 and 3-5 times higher than that of the mono-culture LQRI under the same concentration substrate, respectively. In the presence of 0.6% yeast extract, the highest ethanol concentrations in the co-cultures of LQRI + X514 and LQRI + 39E were rapidly improved and reached 263.5 mmol/L and 143.5 mmol/L, which were approximately 8-22 and 8-12 times higher than that of the mono-culture LQRI under the same concentrations substrate, respectively. The maximum ethanol concentration reached about 263.5 mmol/L (1.2%) in the co-culture of LQRI + X514 grown on 5% Solka Floc in the presence of 0.6% yeast extract, while the maximum ethanol concentration reached 143.5 mmol/L (1.2%) in the co-culture of LQRI + 39E grown on 2% Solka Floc in the presence of 0.6% yeast extract.
在纤维素乙醇生产菌株（嗜热栖热菌LQRI）的单培养分批系统以及LQRI与一种非纤维素乙醇生产菌株（嗜热栖热菌X514或嗜热栖热菌39E）组合的共培养分批系统中，对纤维素类材料发酵生产乙醇进行了评估。结果表明，由LQRI和嗜热栖热菌作为伙伴组成的共培养体系显著提高了乙醇产量和纤维素降解能力。析因实验比较显示，LQRI + X514的共培养体系比LQRI + 39E的共培养体系乙醇产量更高，但在这些共培养体系中，LQRI对纤维素的降解没有显著差异。在没有酵母提取物的情况下，LQRI + X514和LQRI + 39E共培养体系中的最高乙醇浓度分别约为71 mmol/L和36.5 mmol/L，在相同浓度底物下，分别约为单培养LQRI体系的5 - 11倍和3 - 5倍。在存在0.6%酵母提取物的情况下，LQRI + X514和LQRI + 39E共培养体系中的最高乙醇浓度迅速提高，分别达到263.5 mmol/L和143.5 mmol/L，在相同浓度底物下，分别约为单培养LQRI体系的8 - 22倍和8 - 12倍。在0.6%酵母提取物存在的情况下，以5% Solka Floc为底物培养的LQRI + X514共培养体系中，最大乙醇浓度达到约263.5 mmol/L（1.2%），而以2% Solka Floc为底物培养的LQRI + 39E共培养体系中，最大乙醇浓度在0.6%酵母提取物存在的情况下达到143.5 mmol/L（1.2%）。
