Bio-stimulation with Bacillus subtilis to realize sucrose wastewater one-step treatment and resource recovery by Aerobic Anoxygenic Phototrophic Bacteria

Bacillus subtilis is a typical strain to bio-stimulate the bioactivity of microorganisms. This paper employed Bacillus subtilis to stimulate lab-cultivated photosynthetic bacteria consortium to treat high COD wastewater under light-aerobic condition. The effluent of sucrose wastewater had COD and NH3-N of 66.22 and 7.65 mg/L, which satisfied the national discharge standard. Thus, a one-step wastewater treatment was realized. Further, with optimum inoculating ratio of 1/50 Bacillus subtilis, the biomass reached 3247 mg/L. Especially, the protein content, carotenoids and bacteriochlorophyll of biomass was 30%, 50%, 75% higher than that of control. Thus, excellent resource recovery was achieved. Further analysis showed that the catalase activity decreased with the increase of inoculation rate of Bacillus subtilis. As for the bacterial composition, the proportion of Ectothiorhodospiraceae, an identified Aerobic Anoxygenic Phototrophic Bacteria (AAPB), increased to 42%. This paper provides a novel way to achieve one-step purification and resource recovery for concentrated wastewater.