State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China.
State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China.
Biotechnol Adv. 2021 Jan-Feb;46:107679. doi: 10.1016/j.biotechadv.2020.107679. Epub 2020 Dec 11.
Ethanol-type fermentation (ETF) is one of three fermentation types during the acidogenesis of the anaerobic biological treatment. Ethanoligenens, a representative genus of ETF, displays acidophilic, autoaggregative, and ethanol-H co-producing characteristics and facilitates subsequent methanogenesis. Here, the latest advances in the molecular mechanisms of the metabolic regulation of ethanol-H co-producing bacteria based on multi-omics studies were comprehensively reviewed. Comparative genomics demonstrated a low genetic similarity between Ethanoligenens and other hydrogen-producing genera. FeFe‑hydrogenases (FeFe-Hases) and pyruvate ferredoxin oxidoreductase (PFOR) played critical roles in the ethanol-H co-metabolic pathway of Ethanoligenens. Global transcriptome analysis revealed that highly expressed [FeFe]-Hases and ferredoxins drove hydrogen production by Ethanoligenens at low pH conditions (4.0-4.5). Quantitative proteomic analysis also proved that this genus resists acetic acid-induced intracellular acidification through the up-regulated expression of pyrimidine metabolism related proteins. The autoaggregation of Ethanoligenen facilitated its granulation with acetate-oxidizing bacteria in co-culture systems and mitigated a fast pH drop, providing a new approach for solving a pH imbalance and improving hydrogen production. In-depth studies of the regulatory mechanism underlying ethanol-H co-production metabolism and the syntrophic interactions of ethanol-H co-producing Ethanoligenens with other microorganisms will provide insights into the improvement of bioenergy recovery in anaerobic biotechnology. The coupling of ETF with other biotechnologies, which based on the regulation of electron flow direction, syntrophic interaction, and metabolic flux, can be potential strategies to enhance the cascade recovery of energy and resources.
乙醇型发酵（ETF）是厌氧生物处理中酸生成阶段的三种发酵类型之一。乙醇发酵菌属是 ETF 的一个代表性属，具有嗜酸、自聚集和乙醇-H 共生产的特性，有利于随后的产甲烷作用。本文综合评述了基于多组学研究的乙醇-H 共生产菌代谢调控的分子机制的最新进展。比较基因组学表明，乙醇发酵菌与其他产氢属之间的遗传相似度较低。铁铁氢化酶（FeFe-Hases）和丙酮酸铁氧还蛋白氧化还原酶（PFOR）在乙醇发酵菌的乙醇-H 共代谢途径中发挥着关键作用。全转录组分析表明，高表达的[FeFe]-Hases 和铁氧还蛋白在低 pH 值（4.0-4.5）条件下驱动乙醇发酵菌产氢。定量蛋白质组学分析也证明，该属通过上调嘧啶代谢相关蛋白的表达来抵抗乙酸诱导的细胞内酸化。乙醇发酵菌的自聚集有助于其与乙酸氧化菌在共培养系统中形成颗粒，并减轻 pH 值的快速下降，为解决 pH 值失衡和提高产氢提供了一种新方法。深入研究乙醇-H 共生产代谢的调控机制以及乙醇-H 共生产乙醇发酵菌与其他微生物的共营养相互作用，将为提高厌氧生物技术中的生物能源回收提供深入了解。基于电子流方向、共营养相互作用和代谢通量调控的 ETF 与其他生物技术的耦合，可以是增强能量和资源级联回收的潜在策略。
