Bergen Community College (BCC) soils were used to generate mud suspensions to construct microbial fuel cells (MFCs) with the anode buried with the mud, while the cathode rested on top. MFCs incubated at 37°C showed more electrical output and electrogenic bacteria than those grown at 25°C. The most productive MFC generated a maximum of 80 microwatts with 1.67 × 10⁹ electrogenic microorganisms. 16S rRNA clone libraries were developed and analyzed using next generation sequencing. The average soil bacterial community was comprised of 17 different bacterial phyla. The most abundant bacterial phyla in soils were Actinobacteria (33.76%), Proteobacteria (25.60%), Chloroflexi (9.70%), Acidobacteria (8.98%), and Planctomycetes (6.10%). The 16S rRNA genes of the biofilm grown on the anode of the most efficient MFCs were amplified and cloned to determine the composition and diversity of electrogenic bacteria. The average bacterial community was comprised of 21 bacterial phyla. The most abundant bacterial phyla in MFCs were Firmicutes (18.98%), Proteobacteria (18.79%), Actinobacteria (13.63%), Chloroflexi (11.43%), and Planctomycetes (7.91%). All MFCs showing electricity generation had an increase in Firmicutes sequences at all taxonomical levels. The MFC lacking large numbers of Firmicutes did not show electrogenic bacteria nor any electrical production. Bacteria belonging to the phylum Firmicutes provided an important contribution to the development of diverse, stable, and sustainable electrogenic bacterial communities.