Tóm tắt

In recent years, granular activated carbon (GAC) has been extensively investigated as an additive for pro-moting electroactive microbiome to enhance anaerobic digestion performance. This study first demon-strates that GAC particles doped with magnetite can significantly improve the syntrophic degradationrnof propionate, a substrate that is not readily degraded by microbial communities in the anaerobic diges-tion process. The bioreactor amended with magnetite doped GAC achieved the highest methane produc-tion (220 mL/g COD) and COD removal (70%) in fed-batch tests, which were 1.5 and 1.2 times of those inrncontrol and GAC amended bioreactors, respectively. The acetate accumulation was found to be correlatedrnwith methane production. Quantitative comparison of microbial communities suggested that the addi-tion of GAC or doped GAC didn’t achieve higher microbial biomass compared to control. Instead, multiplernknown electroactive bacterial genera (Shewanella, Pseudomonas, Geobacter, and Desulfuromonas) werernselectively enriched along with higher levels of heme-binding proteins in the bioreactors amended withrnmagnetite doped GAC (1.1u000110rn5rncells/mL) and GAC (8.4u000110rn4rncells/mL) in comparison to controlrn(2.5u000110rn4rncells/mL). Thus, our results suggest that tailoring GAC particles though doping with mag-netite can provide an efficient method to achieve high-performance anaerobic digestion