Dynamic Flux Balance Modeling of Microbial Co-Cultures for Efficient Batch Fermentation of Glucose and Xylose Mixtures
Dynamic Flux Balance Modeling of Microbial Co-Cultures for Efficient Batch Fermentation of Glucose and Xylose Mixtures
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DOI：
10.1002/bit.22954
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发表时间：
2011-02-01
影响因子：
3.8
通讯作者：
Henson, Michael A.
中科院分区：
文献类型：
--
作者：
Hanly, Timothy J.;Henson, Michael A.
组成木质纤维素生物质的戊糖和己糖的连续摄取限制了纯微生物培养物有效生产增值生物产品的能力。在这项工作中，我们使用动态通量平衡模型来检查底物选择性微生物的混合培养物提高葡萄糖/木糖混合物的利用率并将这些混合底物转化为产品的能力。分别针对仅摄取葡萄糖和木糖而设计的大肠杆菌菌株 ALS1008 和 ZSC113 的共培养模拟表明，在之前的实验研究中观察到的批量底物消耗的改善主要是由于相对于野生型大肠杆菌 ZSC113 木糖摄取的增加。将经过改造以消除葡萄糖摄取的大肠杆菌菌株 ZSC113 与只能代谢葡萄糖的野生型酿酒酵母进行计算共培养，以确定与野生型大肠杆菌和经过改造以联合摄取葡萄糖和木糖的酿酒酵母菌株 RWB218 的纯培养物相比，共培养是否能够增强乙醇产量。在两种微生物在共同环境条件下最佳生长的简化假设下，菌株接种物和需氧到厌氧转换时间的优化使乙醇生产率比纯培养物几乎增加了一倍。为了检查在非最佳 pH 值和温度值下菌株生长速率降低的影响，进行了盈亏平衡分析，以确定单个菌株底物摄取速率可能的降低，从而导致与最佳纯培养物相同的预测乙醇生产率。生物技术。生物工程。 2011；108：376-385。 (C) 2010 年 Wiley 期刊公司。
Sequential uptake of pentose and hexose sugars that compose lignocellulosic biomass limits the ability of pure microbial cultures to efficiently produce value-added bioproducts. In this work, we used dynamic flux balance modeling to examine the capability of mixed cultures of substrate-selective microbes to improve the utilization of glucose/xylose mixtures and to convert these mixed substrates into products. Co-culture simulations of Escherichia coli strains ALS1008 and ZSC113, engineered for glucose and xylose only uptake respectively, indicated that improvements in batch substrate consumption observed in previous experimental studies resulted primarily from an increase in ZSC113 xylose uptake relative to wild-type E. coli. The E. coli strain ZSC113 engineered for the elimination of glucose uptake was computationally co-cultured with wild-type Saccharomyces cerevisiae, which can only metabolize glucose, to determine if the co-culture was capable of enhanced ethanol production compared to pure cultures of wild-type E. coli and the S. cerevisiae strain RWB218 engineered for combined glucose and xylose uptake. Under the simplifying assumption that both microbes grow optimally under common environmental conditions, optimization of the strain inoculum and the aerobic to anaerobic switching time produced an almost twofold increase in ethanol productivity over the pure cultures. To examine the effect of reduced strain growth rates at non-optimal pH and temperature values, a break even analysis was performed to determine possible reductions in individual strain substrate uptake rates that resulted in the same predicted ethanol productivity as the best pure culture. Biotechnol. Bioeng. 2011;108: 376-385. (C) 2010 Wiley Periodicals, Inc.