Utilization of proteinaceous materials for power generation in a mediatorless microbial fuel cell by a new electrogenic bacteria Lysinibacillus sphaericus VA5

•Role of a bacterial strain has been shown in MFC which was not used previously.•Bacteria used protein-based substrates over sugar due to lack of specific enzymes.•The maximum Power density obtained was 85 mW/m2.•Findings suggest the presence of electroactive compounds generated by the bacteria.

In this study, a bacterial strain, Lysinibacillus sphaericus which is relatively new in the vast list of biocatalysts known to produce electricity has been tested for its potential in power production. It is cited from the literature that the organism is deficient in some sugar or polysaccharide processing enzymes and thus is tested for its ability to utilize substrates mainly rich in protein components like beef extract and with successive production of electricity. The particular species has been found to generate a maximum power density of 85 mW/m2 and current density of ≈270 mA/m2 using graphite felt as electrode. The maximum Open Circuit Voltage and current has been noted as 0.7 Vand 0.8 mA during these operational cycles. Cyclic voltammetry studies indicate the presence of some electroactive compounds which can facilitate electron transfer from bacteria to electrode. The number of electrogens able to generate electricity in mediator free conditions are few, and the study introduces more divergence to that population. Substrate specificity and electricity generation efficacy of the strain in treating wastewater, specially rich in protein content has been reported in the study. As the species has been found to be efficient in utilizing proteinaceous material, the technique can be useful to treat specific type of wastewaters like wastewater from slaughterhouses or from meat packaging industry. Treating them in a more economical way which generates electricity as a outcome must be preferred over the conventional aerobic treatments. Emphasizing on substrate specificity, the study introduces this novel Lysinibacillus strain as a potent biocatalyst and its sustainable role in MFC application for bioenergy generation.

Graphical abstractSchematic representation of microbial fuel cell operation using complex material as substrate.Figure optionsDownload full-size imageDownload as PowerPoint slide