Anaerobic fungi are among the most active plant‐degrading microbes in nature. Increased insight into the mechanisms and environmental cues that regulate fungal hydrolysis would better inform bioprocessing strategies to depolymerize lignocellulose. Here, we compare the response of three strains of anaerobic fungi (Piromyces finnis, Anaeromyces robustus, and Neocallimastix californiae) to catabolite regulation by simple carbohydrates. Anaerobic fungi exhibited high enzymatic activity against crystalline cellulose, which was repressed upon incubation with free sugars. Cellulolytic degradation was also inhibited when fungi were exposed to sugars they did not metabolize, suggesting a general mode of catabolite repression. RNA‐Seq experiments in the presence of excess glucose confirmed repression of carbohydrate active enzymes during sugar uptake, and offer a path towards unmasking the function of co‐regulated genes that could be involved in biomass degradation. Overall, these results suggest that sugar‐rich hydrolysates tune the behavior of anaerobic fungi by dampening production of their biomass‐degrading enzymes. © 2018 American Institute of Chemical Engineers AIChE J, 64: 4263–4270, 2018

中文翻译：

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生物质降解酶在厌氧性肠道真菌中被抑制

厌氧真菌是自然界中最活跃的植物降解微生物之一。对调节真菌水解的机制和环境线索的深入了解将更好地为生物加工策略提供解聚木质纤维素的依据。在这里，我们比较了三种厌氧真菌菌株的反应（Piromyces finnis，Anaeromycesrobustus和Neocallimastix californiae）。）通过简单的碳水化合物来调节分解代谢物。厌氧真菌对结晶纤维素表现出很高的酶促活性，与游离糖孵育后被抑制。当真菌暴露于不代谢的糖时，纤维素分解的降解也受到抑制，这表明了分解代谢物阻抑的一般模式。在存在过量葡萄糖的条件下进行RNA-Seq实验证实了糖吸收过程中碳水化合物活性酶的抑制作用，并为揭示可能参与生物量降解的共同调控基因的功能提供了一条途径。总体而言，这些结果表明，富含糖的水解产物可通过抑制生物质降解酶的产生来调节厌氧真菌的行为。©2018美国化学工程师学会AIChE J，64：4263-4270，2018