Revealing mechanism of micro-aeration for enhancing volatile fatty acids production from swine manure

• Published in: Bioresource technology 2022-12, Vol.365, p.128140-128140, Article 128140
• Main Authors: Cao, Qitao, Zhang, Wanqin, Lian, Tianjing, Wang, Shunli, Yin, Fubin, Zhou, Tanlong, Wei, Xiaoman, Dong, Hongmin
• Format: Article
• Language: English
• Subjects: Acid production; Agricultural waste; Bio-fermentation; Carbon mass balance; Micro-oxygen environment; Microbial communities
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2022.128140

[Display omitted] •Air-micro-aeration had significant improvement with VFAs increased by 22.4%.•Air-micro-aeration at ORP +5.5 mV higher than reference ORP was favorable to VFAs.•Different gas micro-aeration did not achieve uniform mixing.•Air-micro-aeration promoted electron transfer activity and energy generation.•Consumption and conversion of VFAs by methanogens were slow by Air-micro-aeration. Micro-aeration is considered a new strategy for improving volatile fatty acids (VFAs) production of agricultural waste. This study investigated the effect and mechanism of micro-aeration of air and oxygen (O2) on VFAs production from swine manure. The results showed that Air-micro-aeration had the most significant improvement effect, with the highest VFAs of 8.21 g/L, which was increased by 22.4%. Moreover, the mixing effects of different micro-aeration were limited, and the microbial communities significantly varied. Firmicutes and Bacteroidota were the dominant hydrolytic and acidogenic bacteria, and Air-micro-aeration preferentially promoted electron transfer activity and energy generation. Methanosarcina, Methanocorpusculum, and Methanobrevibacter can adapt to environmental changes according to their different oxygen tolerance, and the consumption and conversion of VFAs by methanogens were slow under Air-micro-aeration condition. This study revealed mechanism of micro-aeration for improving VFAs production from swine manure, providing a theoretical basis for micro-aeration regulation optimization.