Anaerobic co-digester microbiome during food waste valorization reveals Methanosaeta mediated methanogenesis with improved carbohydrate and lipid metabolism. (July 2021)

• Record Type: Journal Article
• Authors: Patil, Swapnil M.; Kurade, Mayur B.; Basak, Bikram; Saha, Shouvik; Jang, Min; Kim, Sang-Hyoun; Jeon, Byong-Hun
• Is Part Of: Bioresource technology. Volume 332(2021)
• Publication Date: 2021-07
• Subjects: Anaerobic co-digestion -- Food waste -- Syntrophism -- Methanogens -- KEGG pathways; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2021.125123
• Languages: English
• ISSNs: 0960-8524

Abstract

Graphical abstract: Highlights: Food waste (FW) addition (2–6% v/v) enhanced methanogenesis. 4% FW enhanced methane production by 8-fold, with a 99% reduction of long-chain fatty acids. Overloading of the reactors with FW higher than 6% decreased methane production by ~52%. The dominance of Methanosaeta (80.5%) and Methanosarcina (3.1%) observed at 4% FW. High FW concentrations (>6%) leads to the accumulation of VFAs and inhibits methanogenic microbes. Abstract: This study determines the optimum food waste (FW) loading in an anaerobic digester for methane production. Interrelation between the degradation mechanism and microbial community composition was assessed through in-depth metabolic pathway analysis and gene quantification. Higher methane production and short lag phase were observed in the FW reactors with low substrate loadings (<4% v/v) while extended lag phase and incomplete substrate utilization were observed in the reactors fed with higher substrates (>6% v/v). The long-chain fatty acids (LCFAs) degradation was influenced by initial FW loading, and up to 99% LCFA degradation occurred at 4% FW reactor. The addition of 8 to 10% FW substrate inhibited methanogenesis due to the accumulation of volatile fatty acids (VFA) and low LCFA degradation. Under optimal conditions of substrate loading, Methanosaeta and Methanosarcina were abundant, indicating their role in methanogenesis and syntrophic acetogenesis, along with enhanced metabolic pathways specific for carbohydrate and lipid metabolism.