Effect of static magnetic field on microbial community during anaerobic digestion

Abstract

Dairy wastewater is characterized by high concentration of organic compounds and is commonly used for energy production. Methods for enhancement of biogas production include application of magnetizers on the digester to induce static magnetic field (SMF). The study aimed at investigation of Bacteria and Archaea communities during anaerobic digestion of model dairy wastewater exposed to SMF. Magnetic field caused a significant increase in methane production to 373.2 mL/g VS compared to 200.2 mL/g VS in a control reactor and methane content to 56.8% compared to 49.1% in a control reactor. In both reactors, the biomass was dominated by Trichococcus sp. The relative abundance of lactic acid bacteria was of about 10% higher in the reactor exposed to SMF. This higher number of Lactobacillales resulted from a higher acetate production, which additionally caused enhanced growth of Methanosarcinacaea in the reactor exposed to SMF. SMF also stimulated the growth of hydrogenotrophic methanogens.