Utilization of <i>Chlorella vulgaris</i> biomass in microbial fuel cell as a feed and the study on its degradation pathway

Microbial fuel cells (MFCs) represent an advanced and environmentally friendly bioenergy technology with significant potential for simultaneous power generation and wastewater treatment. This study specifically compared the anodic performance of MFCs with <i>Chlorella vulgaris</i> versus those fed with acetate. Dual-chamber MFCs were constructed for simultaneous electricity generation and wastewater treatment. In addition, microbial communities of both the MFCs and the gene function of MFC-Ch were analyzed through metagenomic sequencing. When comparing all the electrochemical parameters produced from MFCs, MFC-Ch is slightly more efficient than MFC-A. Metagenomic analysis showed that <i>Proteobacteria</i> was the predominant phylum in MFC-A, whereas <i>Bacteroidota</i> was predominant in MFC-Ch. COG (Clusters of Orthologous Groups) analysis of the primary metabolic pathways in the anolyte of MFC-Ch revealed a relatively high abundance of genes associated with several metabolic pathways during MFC operation, including amino acid transport and metabolism, carbohydrate transport and metabolism, and coenzyme transport and metabolism. The study on carbohydrate and protein degradation indicated that protein metabolism occurred to a greater extent than carbohydrate metabolism. This aligns with the known ability of some bacteria present in the sludge to promote amino acid metabolism in MFCs, a finding further supported by the positive correlation observed in the COG analysis.