Role of Pseudomonas aeruginosa biofilm formation in mediator less Microbial fuel cell

The research includes Gram-positive bacterium with rod-shaped cells was isolated from the anodic compartment of a microbial fuel cells (MFCs). The isolate was identified to be one of the Bacillus species dominating the anodic microbial community of the MFC, During the closed circuit experiments, biofilm formation from anode blocks indicated that the two species investigated the viability was higher adjacent to the electrode. In culture experiment with Pseudomonas spp. and Bacillus produced more current compared to the pure cultures, Pseudomonas spp. and Bacillus spp. separately generated 2.5 and 0.2 mA respectively while together the highest current generated was 4.6 mA. And levelled off among 5-7 after which it began to decrease. The biofilm height of Pseudomonas spp. was light pellicle on medium surface and on tube wall and that for Bacillus spp. was light pellicle on tube walls and at medium surface. Both developed smaller micro-colonies over the top of the biofilm layer. Biofilm form in Gram negative are flatter and more uniform than the Gram positive. We suggest that the most active part of the biofilm, playing a major role in the extracellular electron transfer (EET) process, the electrode. The decreasing viability away from the anode can rather be attributed to limitations for the electron transfer towards the electrode than substrate limitation. The overall concept that the Gram-positive Bacilli use electron shuttles produced by other bacteria is intriguing. The interaction of Bacillus spp. with Pseudomonas spp., more specifically with secondary metabolites produced by Pseudomonas spp., and the role of other factors such as quorum-sensing molecules and/or other mediators