适应性进化策略强化厌氧产氢菌群的发酵效能

Adaptive Evolution Strategy Enhancing Biohydrogen Production Via Anaerobic Mixed Culture

摘要:

厌氧发酵产氢菌群中微生物的多样性造成了其在生理生化行为上的异质性,如对有机酸胁迫响应的不一致性,这种异质性形成产氢过程中的"短板效应",限制了菌群整体发酵能力。以外源丁酸胁迫结合选择性化学抑制剂作为复合选择性压力,在连续流中对产氢菌群进行适应性进化,其目的在于消除菌群中导致"短板效应"的微生物,同时富集带有有益进化的产氢细菌,从而强化厌氧菌群的整体发酵效能。分析表明,进化菌群产氢效能的提高主要归因于耐酸能力的提高、竞争途径的弱化、氢化酶和NADH-铁氧还蛋白氧化还原酶(NADH-ferredoxin oxidireductase)活性的提高。

Abstract:

Microbial diversity of mixed culture can result in substantial heterogeneity in physiological and biochemical behaviors such as responses against stress.Such differences can cause "cask effect" during H2 production,and thereby restrict the overall production capacity.In this study,butyric acid stress combined with selective chemical inhibitors was used as the selection pressure to evolve mixed culture in continuous operation.By the adaptive evolution,H2 production capacity via mixed culture can be enhanced by removing the bacteria causing "cask effect" and enriching functional H2-producing bacteria obtaining beneficial evolution.The enhancement was primarily driven by increased acid tolerance,weakened competing pathways,higher activity of hydrogenase and NADH-ferredoxin oxidoreductase(NFOR).