2.4. PSB wastewater treatment experimental setup
Bioreactors (1000 ml Erlenmeyer flask) were sterilized at 121 °C for 20 min before being filled with 600 ml artificial brewery wastewater. The initial PSB concentration was 260 mg/L dry weight. Magnetic stirrers were used to mix bacteria and wastewater uniformly. The inoculated bacteria grew in the bio reactors exponentially. Three different light–oxygen conditions were selected as follows: Light–anaerobic condition. Two 60-watt incandescent lamps were used to keep the light intensity at 2000 lux by adjusting the distance between bioreactor and the lamps. The distance ranged from 5 to 8 cm. After saturating the liquid and headspace with high purity nitrogen, the bioreactor was sealed with a gas tight membrane to maintain anaerobic conditions.