Regulating effects of Fe/C materials on thermophilic anaerobic digestion of kitchen waste: Digestive performances and methanogenic metabolism pathways. (15th January 2023)

• Record Type: Journal Article
• Authors: Chen, Yongdong; Li, Lei; Liu, Haoyu; Yang, Donghai; Liu, Wenxuan; Yang, Dongye; Dai, Xiaohu; Chen, Yanhua
• Is Part Of: Fuel. Volume 332(2023)Part 2
• Publication Date: 2023-01-15
• Subjects: Exogenous materials -- Kitchen waste -- Thermophilic anaerobic digestion -- Microbiological approach -- Methanogenic metabolism pathway; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2022.126140
• Languages: English
• ISSNs: 0016-2361

Abstract

Graphical abstract: Highlights: Dissolution and hydrolysis in anaerobic digestion were enhanced by C addition. Fe addition significantly enriched the relative abundance of Methanothermobacter . Fe addition enhanced the syntrophic acetic acid oxidation pathway. The abundances of key enzymes in methanogenesis were enhanced by Fe and C addition. No clear evidence proved that DIET occurred and contributed in this study. Abstract: This study aimed to evaluate the effects of typical exogenous materials (Fe and C) addition on the performances of kitchen waste thermophilic (55 °C) anaerobic digestion in semi-continuous system. The expression of key enzymes in methanogenesis were demonstrated by microbiological approach, and the regulating effectsf Fe and C addition on methanogenic metabolism pathway were specially explored. Four anaerobic digestion systems (TAD, TAD + Fe, TAD + C and TAD + Fe + C) were carried out, and the running period lasted for 120 days, which was divided into four stages according to organic loading rates (OLRs) from 1.05 to 4.22 gVS/L/day. From this study, C addition improved soluble polysaccharide (sPolysaccharide), soluble protein (sProtein), soluble total organic carbon (sTOC) concentrations and hydrolase (amylase, protease and lipase) activities, while Fe addition facilitated the subsequent degradation of volatile fatty acids (VFAs). As a result, the average methane yields were promoted from 478.0 (TAD) to 487 (TAD + Fe), 597 (TAD + C) and 647.3 mL/gVS/day (TAD + Fe + C), respectively. For microbial communities, C addition promoted the relative abundances of hydrolytic bacteria ( Defluviitoga ), while Fe addition realized the directional enrichment of Methanothermobacter, and improved hydrogenotrophic methanogenesis ratios from 30.81 % (TAD) to 52.27 % (TAD + Fe) and 64.40 % (TAD + Fe + C). According to the expression of key enzymes in methanogenic metabolism pathways, Fe addition enhanced the syntrophic acetic acid oxidation and hydrogenotrophic methanogenesis pathway, realizing the conversion of dominated methanogenic metabolism pathway from aceticlastic methanogenesis to hydrogenotrophic methanogenesis. This study is of great significance to exposit the behaviors of conductive materials during thermophilic digestion of kitchen waste.