Efficient production of l-lactic acid by an engineered Thermoanaerobacterium aotearoense with broad substrate specificity.
Efficient production of l-lactic acid by an engineered Thermoanaerobacterium aotearoense with broad substrate specificity.
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DOI：
10.1186/1754-6834-6-124
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发表时间：
2013-08-28
影响因子：
6.3
通讯作者：
Wang X
中科院分区：
文献类型：
--
作者：
Yang X;Lai Z;Lai C;Zhu M;Li S;Wang J;Wang X
有效地将木质纤维素生物质转化为光纯乳酸是经济生产可生物降解聚乳酸的关键挑战。最近分离出的一种菌株，热厌氧细菌aotearoense SCUT27，由于其广泛的底物特异性，有望成为一种高效的生物质产乳酸细菌。此外，其严格的厌氧和嗜热特性抑制了其他微生物的污染。在此，我们报告了通过T. aotearoense SCUT27的同源重组实现碳通量重定向，从而显著提高了各种木质纤维素衍生糖的乳酸生产浓度和产率。T. aotearoense SCUT27被设计为阻断醋酸形成途径以提高乳酸产量。以10 g/L葡萄糖和10 g/L木糖为底物，乳酸产量分别提高1.8倍和2.1倍。工程菌株LA1002在50 g/L底物条件下，最大L -乳酸产率为0.93 g/g葡萄糖，光学纯度为99.3%，与理论值（1.0 g/g葡萄糖）非常接近。特别是，LA1002在发酵48 h后，以10 g/L木聚糖为单底物，未经任何预处理，乳酸浓度达到了前所未有的3.20 g/L。对L -乳酸进行了非灭菌发酵生产，乳酸浓度和产率分别达到44.89 g/L和0.89 g/g混合糖。阻断T. aotearoense SCUT27的醋酸形成途径可显著提高l-乳酸的产量和产量。据我们所知，考虑到最终浓度、产量和发酵时间，这是以木聚糖为唯一碳源的发酵产乳酸的最佳表现。此外，应该提到的是，葡萄糖和木糖非灭菌同时发酵的性能与正常灭菌培养的性能非常接近。所有这些结果表明，突变菌株LA1002是一个新的有希望的候选菌株，可以有效地从木质纤维素生物质中生产光纯l-乳酸。
Efficient conversion of lignocellulosic biomass to optically pure lactic acid is a key challenge for the economical production of biodegradable poly-lactic acid. A recently isolated strain, Thermoanaerobacterium aotearoense SCUT27, is promising as an efficient lactic acid production bacterium from biomass due to its broad substrate specificity. Additionally, its strictly anaerobic and thermophilic characteristics suppress contamination from other microoragnisms. Herein, we report the significant improvements of concentration and yield in lactic acid production from various lignocellulosic derived sugars, achieved by the carbon flux redirection through homologous recombination in T. aotearoense SCUT27. T. aotearoense SCUT27 was engineered to block the acetic acid formation pathway to improve the lactic acid production. The genetic manipulation resulted in 1.8 and 2.1 fold increase of the lactic acid yield using 10 g/L of glucose or 10 g/L of xylose as substrate, respectively. The maximum l-lactic acid yield of 0.93 g/g glucose with an optical purity of 99.3% was obtained by the engineered strain, designated as LA1002, from 50 g/L of substrate, which is very close to the theoretical value (1.0 g/g of glucose). In particular, LA1002 produced lactic acid at an unprecedented concentration up to 3.20 g/L using 10 g/L xylan as the single substrate without any pretreatment after 48 h fermentation. The non-sterilized fermentative production of l-lactic acid was also carried out, achieving values of 44.89 g/L and 0.89 g/g mixed sugar for lactic acid concentration and yield, respectively. Blocking acetic acid formation pathway in T. aotearoense SCUT27 increased l-lactic acid production and yield dramatically. To our best knowledge, this is the best performance of fermentation on lactic acid production using xylan as the sole carbon source, considering the final concentration, yield and fermentation time. In addition, it should be mentioned that the performance of non-sterilized simultaneous fermentation from glucose and xylose was very close to that of normal sterilized cultivation. All these results used the mutant strain, LA1002, indicated that it is a new promising candidate for the effective production of optically pure l-lactic acid from lignocellulosic biomass.
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影响因子：
9.8
作者：
Hu, Chun-Yi;Chi, Da-Jun;Chen, Yo-Chia
通讯作者：
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影响因子：
9.8
作者：
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11.4
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作者：
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通讯作者：
Paalme, T