Isolation and Characterization of Bacteria with High Electroactive Potential from Poultry Wastewater

Biology (Basel). 2023 Apr 20;12(4):623. doi: 10.3390/biology12040623.

Abstract

Natural resources are in short supply, and the ecosystem is being damaged as a result of the overuse of fossil fuels. The creation of novel technology is greatly desired for investigating renewable and sustainable energy sources. Microorganisms have received a lot of interest recently for their potential to transform organic waste into sustainable energy and high-value goods. New exoelectrogens that can transmit electrons to electrodes and remove specific wastewater contaminants are expected to be studied. In this study, we examined three distinct samples (as determined by chemical oxygen demand and pH) that can be used as anolytes to generate power in single-chamber and double-chamber microbial fuel cells using graphite electrodes. Wastewater from poultry farms was studied as an exoelectrogenic anolyte for microbial fuel cell power generation. The study examined 10 different bacterial strains, numbered A1 through A10. Due to their highly anticipated capacity to metabolize organic/inorganic chemicals, the diverse range of microorganisms found in poultry wastewater inspired us to investigate the viability of generating electricity using microbial fuel cells. From the investigated bacterial strains, the highest voltage outputs were produced by strains A1 (Lysinibacillus sphaericus) and A2 (Bacillus cereus), respectively, at 402 mV and 350 mV. Among the 10 different bacterial strains, strain A6 generated the least amount of electricity, measuring 35.03 mV. Furthermore, a maximum power density of 16.16 1.02 mW/m2 was achieved by the microbial fuel cell using strain A1, significantly outperforming the microbial fuel cell using a sterile medium. The strain A2 showed significant current and power densities of 35 1.12 mA/m2 and 12.25 1.05 mW/m2, respectively. Moreover, in the two representative strains, chemical oxygen demand removal and Coulombic efficiency were noted. Samples from the effluent anode chamber were taken in order to gauge the effectiveness of chemical oxygen demand removal. Wastewater had an initial chemical oxygen demand content of 350 mg/L on average. Strains A1 and A2 decomposed 94.28% and 91.71%, respectively, of the organic substrate, according to the chemical oxygen demand removal efficiency values after 72 h. Strains A1 and A2 had electron donor oxidation efficiencies for 72 h of 54.1% and 60.67%, respectively. The Coulombic efficiency increased as the chemical oxygen demand decreased, indicating greater microbial electroactivity. With representative strains A1 and A2, Coulombic efficiencies of 10% and 3.5%, respectively, were obtained in the microbial fuel cell. The findings of this study greatly advance the field as a viable source of power technology for alternative energy in the future, which is important given the depletion of natural resources.

Keywords: anode-respiring bacteria; chemical oxygen demand; electricity; electroactive microorganisms microbial fuel cell; extracellular electron transfer; gut microbiome; voltage.