Improving the power generation performances of Gram-positive electricigens by regulating the peptidoglycan layer with lysozyme.

The power generation performance of a microbial fuel cell (MFC) greatly depends on the relative amount of electricigens in the anodic microbial community. Running the MFC multiple times can practically enrich the electricigens, and thus improve its power generation efficiency. However, Gram-positive electricigens cannot be enriched well because of their thick non-conductive peptidoglycan layer. Herein, we report a new Gram-positive electricigen enrichment method by regulating the peptidoglycan layer of the bacteria using lysozyme. Lysozyme can partially hydrolyze the peptidoglycans layer of Gram-positive Firmicutes to improve the permeability of cell wall, and thus enhance its electricity generation activity. The stimulation of Gram-positive electricigen endows MFCs a high power generation community structure, which results in the power density 42% higher than that of the control sample. Our work has provided a new and simple method for optimizing the anode community structure by regulating weak electricigens in the community with lysozyme.