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Updated: Jun 16, 2025

Continuously-stirred Anaerobic Digester to Convert Organic Wastes into Biogas: System Setup and Basic Operation
Published on: July 13, 2012
Ethanol-type anaerobic digestion enhanced methanogenic performance by stimulating direct interspecies electron
Shuang Zhang1, Yuanyuan Ren2, Pan Zhao1
1Department of Environmental Science and Engineering, School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China.
Abstract:
Ethanol pre-fermentation of food waste effectively alleviates acidification; however, its effects on interspecies electron transfer remain unknown. This study configured the feed according to COD ratios of ethanol: sodium acetate: sodium propionate: sodium butyrate of 5:2:1.5:1.5 (ethanol-type anaerobic digestion) and 0:5:2.5:2.5 (control), and conducted semi-continuous anaerobic digestion (AD) experiments. The results showed that ethanol-type AD increased maximum tolerable organic loading rate (OLR) to 6.0 gCOD/L/d, and increased the methane production by 1.2-14.8 times compared to the control at OLRs of 1.0-5.0 gCOD/L/d. The abundance of the pilA gene, which was associated with direct interspecies electron transfer (DIET), increased by 5.6 times during ethanol-type AD. Hydrogenase genes related to interspecies hydrogen transfer (IHT), including hydA-B, hoxH-Y, hnd, ech, and ehb, were upregulated during ethanol-type AD. Ethanol-type AD improved methanogenic performance and enhanced microbial metabolism by stimulating DIET and IHT.
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