Study on the flocs poly-β-hydroxybutyrate production and process optimization in the bio-flocs technology system

The bio-flocs technology (BFT) was applied in the sequencing batch reactor (SBR) to treat aquaculture wastewater for flocs poly-β-hydroxybutyrate (PHB) accumulation with alternant anaerobic and aerobic conditions. The statistical modeling approach was used to evaluate system performance and to optimize the flocs PHB yield at batch mode. The results show that all variables have significant impact on the response objective, as well as the interactions of the C/N ratio with the flocs biomass concentration (VSS) and anaerobic time, respectively. By process optimization, approximately 150–200 PHB/VSS (mg·g) of flocs PHB yield was achieved in the range of 4–7 g/l of flocs biomass concentration, 15–18 of the C/N ratio and 50–85 min of anaerobic time in the BFT systems. The results demonstrated that a suitable flocs PHB yield can be obtained via optimizing the ex-situ operating strategy, which have potential prebiotic value and practical implication for the sustainable aquaculture.

► Bio-flocs were produced for flocs poly-β-hydroxybutyrate (PHB) accumulation. ► Flocs PHB yield was investigated at batch mode by statistical modeling approach. ► Relationship between flocs PHB yield and parameters was established and checked. ► Optimal flocs PHB yield was investigated and obtained.