Transcriptional profiling reveals molecular basis and novel genetic targets for improved resistance to multiple fermentation inhibitors in Saccharomyces cerevisiae.
Transcriptional profiling reveals molecular basis and novel genetic targets for improved resistance to multiple fermentation inhibitors in Saccharomyces cerevisiae.
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DOI：
10.1186/s13068-015-0418-5
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发表时间：
2016
影响因子：
6.3
通讯作者：
Wei N
中科院分区：
文献类型：
--
作者：
Chen Y;Sheng J;Jiang T;Stevens J;Feng X;Wei N
木质纤维素生物质是一种有前途的可再生生物燃料来源。然而，木质纤维素生物质的预处理产生发酵抑制剂，其不利地影响工业微生物如酿酒酵母（Saccharomyces cerevisiae）的生长并阻止木质纤维素生物燃料的经济生产。发展S.酿酒酵母抑制剂抗性提高的原因在于对抑制剂应激反应的分子基础的不完全理解以及关于增加酵母对混合发酵抑制剂抗性的有效遗传靶点的有限信息。在这项研究中，我们应用比较转录组学分析，以确定乙酸和/或糠醛抗性的分子基础，在S。啤酒。我们最近通过反向代谢工程培育了一株对乙酸、糠醛及其混合物具有上级抗性的酵母菌株YC 1。在这项研究中，我们首先通过RNA测序确定转录变化在YC 1与野生型菌株S-C1在三种不同的抑制剂条件下，包括单独的乙酸，单独的糠醛，乙酸和糠醛的混合物。与S.酿酒酵母的单一和混合抑制剂。具体来说，我们确定了184个共识基因，差异调节，以响应不同的抑制剂耐药性之间的YC 1和S-C1。生物信息学分析接下来揭示了调节这些共有基因的关键转录因子（TF）。鉴定的最高TF Sfp 1 p和Ace 2 p作为菌株优化的过表达靶标进行实验测试。SFP 1基因的过表达将比乙醇生产率提高了近4倍，而ACE 2基因的过表达在乙酸和糠醛的存在下将该速率提高了3倍。SFP 1基因在抗性菌株YC 1中的过表达进一步导致在乙酸和糠醛存在下乙醇生产率增加42%，表明Sfp 1 p在优化酵母菌株以提高对混合发酵抑制剂的耐受性中的作用。确定了酵母对乙酸和糠醛抗性的转录调节。Sfp 1 p和Ace 2 p两个转录因子在提高酵母菌对混合发酵抑制剂的抗性中的功能首次被发现。该研究展示了一个组学指导的代谢工程框架，它可以被开发为一个有前途的策略，以改善复杂的微生物表型。本文的在线版本（doi：10.1186/s13068-015-0418-5）包含补充材料，可供授权用户使用。
Lignocellulosic biomass is a promising source of renewable biofuels. However, pretreatment of lignocellulosic biomass generates fermentation inhibitors that adversely affect the growth of industrial microorganisms such as Saccharomyces cerevisiae and prevent economic production of lignocellulosic biofuels. A critical challenge on developing S. cerevisiae with improved inhibitor resistance lies in incomplete understanding of molecular basis for inhibitor stress response and limited information on effective genetic targets for increasing yeast resistance to mixed fermentation inhibitors. In this study, we applied comparative transcriptomic analysis to determine the molecular basis for acetic acid and/or furfural resistance in S. cerevisiae. We recently developed a yeast strain YC1 with superior resistance to acetic acid, furfural, and their mixture through inverse metabolic engineering. In this study, we first determined transcriptional changes through RNA sequencing in YC1 versus the wild-type strain S-C1 under three different inhibitor conditions, including acetic acid alone, furfural alone, and mixture of acetic acid and furfural. The genes associated with stress responses of S. cerevisiae to single and mixed inhibitors were revealed. Specifically, we identified 184 consensus genes that were differentially regulated in response to the distinct inhibitor resistance between YC1 and S-C1. Bioinformatic analysis next revealed key transcription factors (TFs) that regulate these consensus genes. The top TFs identified, Sfp1p and Ace2p, were experimentally tested as overexpression targets for strain optimization. Overexpression of the SFP1 gene improved specific ethanol productivity by nearly four times, while overexpression of the ACE2 gene enhanced the rate by three times in the presence of acetic acid and furfural. Overexpression of SFP1 gene in the resistant strain YC1 further resulted in 42 % increase in ethanol productivity in the presence of acetic acid and furfural, suggesting the effect of Sfp1p in optimizing the yeast strain for improved tolerance to mixed fermentation inhibitor. Transcriptional regulation underlying yeast resistance to acetic acid and furfural was determined. Two transcription factors, Sfp1p and Ace2p, were uncovered for the first time for their functions in improving yeast resistance to mixed fermentation inhibitors. The study demonstrated an omics-guided metabolic engineering framework, which could be developed as a promising strategy to improve complex microbial phenotypes. The online version of this article (doi:10.1186/s13068-015-0418-5) contains supplementary material, which is available to authorized users.