Inhibition of growth of Zymomonas mobilis by model compounds found in lignocellulosic hydrolysates.
Inhibition of growth of Zymomonas mobilis by model compounds found in lignocellulosic hydrolysates.
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DOI：
10.1186/1754-6834-6-99
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发表时间：
2013-07-09
影响因子：
6.3
通讯作者：
Zhang M
中科院分区：
文献类型：
--
作者：
Franden MA;Pilath HM;Mohagheghi A;Pienkos PT;Zhang M
在生物质原料的预处理和随后在糖化之前的调节期间，产生或引入许多有毒化合物，其抑制微生物生长，并且在许多情况下抑制乙醇的产生。了解水解产物中发现的化合物的毒性作用对于提高发酵过程中的糖利用率和乙醇产率至关重要。在这项研究中，我们建立了一个有用的工具，通过测量生长速率的有毒化合物的存在下，水解产物的毒性进行调查，并检查选择模型抑制剂的醛，有机和无机酸（沿着与各种阳离子），和醇对运动发酵单胞菌8b（ZM 4衍生物）的生长，使用葡萄糖或木糖作为碳源的影响。在Z.在大肠杆菌和酿酒酵母中观察到的醛和有机酸（有一些例外）。我们观察了Z。mobilis 8b对有机酸的耐受性比以前报道的更强，尽管碳源和生长条件在耐受性中起作用。在木糖中的生长被深深地抑制由一元羧酸有机酸相比，在葡萄糖中的生长，而二羧酸表现出很少或没有影响的生长速度在任何基板。此外，阳离子可以按照其毒性的顺序排列，Ca ++>> Na +> NH 4 +> K+。HMF（5-羟甲基糠醛），糠醛和乙酸，观察到有助于抑制Z。在稀酸预处理的玉米秸秆水解产物中，mobilis的生长不以协同方式组合相互作用。进一步证明了Z. Mobilis 8b能够在发酵过程中将醛类糠醛、香草醛、4-羟基苯甲醛和一定程度的双辛醛转化为它们的醇形式（糠基、香草基、4-羟基苄醇和双辛基醇）。本报告中的几个关键发现提供了一种预测水解产物抑制组分毒性贡献的机制，并为潜在的工艺开发提供指导，沿着潜在的未来菌株改良和耐受性策略。
During the pretreatment of biomass feedstocks and subsequent conditioning prior to saccharification, many toxic compounds are produced or introduced which inhibit microbial growth and in many cases, production of ethanol. An understanding of the toxic effects of compounds found in hydrolysate is critical to improving sugar utilization and ethanol yields in the fermentation process. In this study, we established a useful tool for surveying hydrolysate toxicity by measuring growth rates in the presence of toxic compounds, and examined the effects of selected model inhibitors of aldehydes, organic and inorganic acids (along with various cations), and alcohols on growth of Zymomonas mobilis 8b (a ZM4 derivative) using glucose or xylose as the carbon source. Toxicity strongly correlated to hydrophobicity in Z. mobilis, which has been observed in Escherichia coli and Saccharomyces cerevisiae for aldehydes and with some exceptions, organic acids. We observed Z. mobilis 8b to be more tolerant to organic acids than previously reported, although the carbon source and growth conditions play a role in tolerance. Growth in xylose was profoundly inhibited by monocarboxylic organic acids compared to growth in glucose, whereas dicarboxylic acids demonstrated little or no effects on growth rate in either substrate. Furthermore, cations can be ranked in order of their toxicity, Ca++ > > Na+ > NH4+ > K+. HMF (5-hydroxymethylfurfural), furfural and acetate, which were observed to contribute to inhibition of Z. mobilis growth in dilute acid pretreated corn stover hydrolysate, do not interact in a synergistic manner in combination. We provide further evidence that Z. mobilis 8b is capable of converting the aldehydes furfural, vanillin, 4-hydroxybenzaldehyde and to some extent syringaldehyde to their alcohol forms (furfuryl, vanillyl, 4-hydroxybenzyl and syringyl alcohol) during fermentation. Several key findings in this report provide a mechanism for predicting toxic contributions of inhibitory components of hydrolysate and provide guidance for potential process development, along with potential future strain improvement and tolerance strategies.
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影响因子：
3.4
作者：
Helle, S;Cameron, D;Duff, S
通讯作者：
Duff, S
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作者：
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