Laboratory of Biomass Bio-Chemical Conversion, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, PR China; Shandong Minhe Biotechnology Co., Ltd.
Laboratory of Biomass Bio-Chemical Conversion, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, PR China.
Water Res. 2023 Nov 1;246:120711. doi: 10.1016/j.watres.2023.120711. Epub 2023 Oct 8.
The accumulation of volatile fatty acids (VFAs) in anaerobic digestion (AD) systems resulting from food waste overload poses a risk of system collapse. However, limited understanding exists regarding the inhibitory mechanisms and effective strategies to address VFAs-induced stress. This study found that accumulated VFAs exert reactive oxygen species (ROS) stress on indigenous microbiota, particularly impacting methanogens due to their lower antioxidant capability compared to bacteria, which is supposed to be the primary reason for methanogenesis failure. To enhance the VFAs-stressed AD process, microbiome re-assembly using customized propionate-degrading consortia and bioaugmentation with concentrated digestate were implemented. Microbiome re-assembly demonstrated superior efficiency, yielding an average methane yield of 563.6±159.8 mL/L·d and reducing VFAs to undetectable levels for a minimum of 80 days. This strategy improved the abundance of Syntrophomonas, Syntrophobacter and Methanothrix, alleviating ROS stress. Conversely, microbial community in reactor with other strategy experienced an escalating intracellular damage, as indicated by the increase of ROS generation-related genes. This study fills knowledge gaps in stress-related metabolic mechanisms of anaerobic microbiomes exposed to VFAs and microbiome re-assembly to boost methanogenesis process.
由于食物垃圾过载，厌氧消化（AD）系统中挥发性脂肪酸（VFAs）的积累会带来系统崩溃的风险。然而，对于 VFAs 诱导的应激的抑制机制和有效应对策略，我们的了解有限。本研究发现，积累的 VFAs 对本土微生物群落产生了活性氧（ROS）应激，特别是由于其抗氧化能力低于细菌，因此对产甲烷菌的影响更大，这应该是甲烷生成失败的主要原因。为了增强 VFAs 应激的 AD 过程，使用定制的丙酸盐降解菌群进行微生物组再组装，并使用浓缩消化液进行生物增强。微生物组再组装表现出更高的效率，平均甲烷产量为 563.6±159.8 mL/L·d，并将 VFAs 降低到至少 80 天不可检测的水平。该策略提高了产甲烷菌、产琥珀酸菌和产甲烷丝状菌的丰度，缓解了 ROS 应激。相比之下，采用其他策略的反应器中的微生物群落经历了不断加剧的细胞内损伤，这表明与 ROS 产生相关的基因增加。本研究填补了 VFAs 暴露的厌氧微生物群落和微生物组再组装相关代谢机制以及促进甲烷生成过程的应激相关知识空白。
