Potential of Rhodobacter capsulatus grown in anaerobic-light or aerobic-dark conditions as bioremediation agent for biological wastewater treatments.

摘要

The use of microorganisms to clean up wastewater provides a cheaper alternative to\udthe conventional treatment plant. The efficiency of this method can be improved by the choice of\udmicroorganism with the potential of removing contaminants. One such group is photosynthetic\udbacteria. Rhodobacter capsulatus is a purple non-sulfur bacterium (PNSB) found to be capable of\uddifferent metabolic activities depending on the environmental conditions. Cell growth in different\udmedia and conditions was tested, obtaining a concentration of about 108 CFU/mL under aerobic-dark\udand 109 CFU/mL under anaerobic-light conditions. The biomass was then used as a bioremediation\udagent for denitrification and nitrification of municipal wastewater to evaluate the potential to be\udemployed as an additive in biological wastewater treatment. Inoculating a sample of mixed liquor\udwithdrawn from the municipal wastewater treatment plant with R. capsulatus grown in aerobic-dark\udand anaerobic-light conditions caused a significant decrease of N-NO3 (>95%), N-NH3 (70%)\udand SCOD (soluble chemical oxygen demand) (>69%), independent of the growth conditions.\udA preliminary evaluation of costs indicated that R. capsulatus grown in aerobic-dark conditions\udcould be more convenient for industrial application.