A modified Saccharomyces cerevisiae strain that consumes L-arabinose and produces ethanol
A modified Saccharomyces cerevisiae strain that consumes L-arabinose and produces ethanol
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DOI：
10.1128/aem.69.7.4144-4150.2003
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发表时间：
2003-07-01
影响因子：
4.4
通讯作者：
Boles, E
中科院分区：
文献类型：
--
作者：
Becker, J;Boles, E
代谢工程是改善、重定向或产生微生物中新的代谢反应或整个途径的有力方法。在此，我们描述了能够利用戊糖（L）-阿拉伯糖进行生长并将其发酵成乙醇的酿酒酵母菌株的工程化。扩大了S.使酿酒酵母包括戊糖对于在经济上可行的生物质至乙醇发酵工艺中利用该酵母是重要的。在过表达由枯草芽孢杆菌AraA和大肠杆菌AraB和AraD组成的细菌（L）-阿拉伯糖利用途径以及同时过表达（L）-阿拉伯糖转运酵母半乳糖通透酶后，我们能够选择（L）-阿拉伯糖-利用酵母菌株通过在（L）-阿拉伯糖培养基中顺序转移。对该菌株的分子分析（包括DNA微阵列）表明，有效利用（L）-阿拉伯糖的关键先决条件是（L）-核酮糖激酶的活性降低。此外，高的（L）-阿拉伯糖摄取速率和增强的转糖苷酶活性有利于（L）-阿拉伯糖的利用。在以（L）-阿拉伯糖作为唯一碳源的培养基中倍增时间为约7.9小时，乙醇生产速率为0.06至0.08 g乙醇/g（干重）。h（-1）和高的乙醇产率，该酵母菌株可用于纤维素生物质水解产物中己糖和戊糖的有效发酵。
Metabolic engineering is a powerful method to improve, redirect, or generate new metabolic reactions or whole pathways in microorganisms. Here we describe the engineering of a Saccharomyces cerevisiae strain able to utilize the pentose sugar (L)-arabinose for growth and to ferment it to ethanol. Expanding the substrate fermentation range of S. cerevisiae to include pentoses is important for the utilization of this yeast in economically feasible biomass-to-ethanol fermentation processes. After overexpression of a bacterial (L)-arabinose utilization pathway consisting of Bacillus subtilis AraA and Escherichia coli AraB and AraD and simultaneous overexpression of the (L)-arabinose-transporting yeast galactose permease, we were able to select an (L)-arabinose-utilizing yeast strain by sequential transfer in (L)-arabinose media. Molecular analysis of this strain, including DNA microarrays, revealed that the crucial prerequisite for efficient utilization of (L)-arabinose is a lowered activity of (L)-ribulokinase. Moreover, high (L)-arabinose uptake rates and enhanced transaidolase activities favor utilization of (L)-arabinose. With a doubling time of about 7.9 h in a medium with (L)-arabinose as the sole carbon source, an ethanol production rate of 0.06 to 0.08 g of ethanol per g (dry weight) . h(-1) under oxygen-limiting conditions, and high ethanol yields, this yeast strain should be useful for efficient fermentation of hexoses and pentoses in cellulosic biomass hydrolysates.