A Two-stage strategy for polyhydroxybutyrate (PHB) production by continuous Biohydrogen fermenter and sequencing batch reactor from food industry wastewater

The present investigation aimed to enhance the production of polyhydroxybutyrate (PHB). The volatile fatty acid (VFA) was obtained from food industry wastewater using a high-yield VFA extraction system. The experimentation was conducted in two stages: continuous production of VFA and batch production of PHB. During the VFA production, the optimal VFA yield was determined at different hydraulic retention times (HRT) and high chemical oxidation demand (COD). To find the highest PHB production yield, the level of glycerin, ammonia nitrogen, and substrate inoculation in the batch PHB production stage was recorded. At 35 °C and 150 rpm, the wastewater substrate was mixed with urea to achieve an ammonia nitrogen concentration of 2 g/L. The mixed microorganisms were employed to produce PHB. Results revealed that the volatile solids had a PHB yield of 40% (g PHB/g VSS), while the volatile solids (VSS) had 6,900 mg/L. The effluent from the acidification tank can effectively generate PHB to produce VFAs from waste sewage and food industry wastewater. Using various kinds of wastewaters to generate value-added products is an excellent approach to bioenergy generation.