Microbial approach towards anode biofilm engineering enhances extracellular electron transfer for bioenergy production

The application of microbial electrolysis cells (MEC) is a biological approach to enhance growing high amounts of electroactive biofilm for extracellular electron transfer. The electroactive biofilm degrades the organics by oxidizing them at the anode and producing electric energy. The addition of waste-activated sludge (WAS) with fat grease oil (FOG) produces an optimal reactor environment for microbial growth to enhance the exchange of electrons between cells via microbial electrolysis. The novel study investigates the microbial approach to increase the EET in microbial electrolysis cells. Results revealed that metabolites in an EAM grow viable cells that initiate high EET at anode sites. At optimum WAS with FOG addition, the production of volatile fatty acid and current generation yield were 2.94 ± 0.19 g/L and 17.91 ± 7.23 mA, respectively. Analysis of the bio-electrochemical changes showed that the anodic biofilm enhances intercellular electron transfer, increases NADH-NAD ratio 28.6, and increases metabolites yield-fluxes which would be responsible for bio-electricity production. Taken together, results indicated that the electrolysis highlights MEC performance in terms of power generation of 788 mV with 200 mL of anode volume of active viable cells by utilizing WAS with 11% FOG. The engineered strains exhibited excellent workability for power generation and EET activity. This study shed light on the anode biofilm engineering how growth cell volume, intercellular electron transfer, increases NADH-NAD ratio is a evidence to increase the EET of EAB for efficient current production.