Biomass and carotenoid production in photosynthetic bacteria wastewater treatment: Effects of light intensity

Abstract

This study investigated the feasibility of using photosynthetic bacteria (PSB) to produce biomass and carotenoid while treating wastewater. The effects of light intensity on the biomass, carotenoid and bacteriochlorophyll accumulation in together with pollutant removal were studied. Results showed that it was feasible to use PSB to treat wastewater as well as to produce biomass or carotenoid. 2000lux was an optimal intensity for biomass production and COD removal, and the corresponding values were 2645mg/L and 94.7%. 8000lux was an optimal light intensity for carotenoid production (1.455mg/L). Mechanism analysis displayed that the greater the bacteriochlorophyll and carotenoid were secreted, the lower the light conversion efficiency turned out to be. The highest light conversion efficiency was achieved at 500lux; the ATP production, biomass production, and COD removal were the highest at 2000lux, but the bacteriochlorophyll and carotenoid content were the lowest at 2000lux.