Sustainable multistage process for enhanced productivity of bioplastics from waste remediation through aerobic dynamic feeding strategy: Process integration for up-scaling

• Integrating bio-H2 with PHA production in a multistage approach.
• VFA rich effluents from acidogenic fermentation were used for PHA production.
• Aerobic dynamic feeding strategy was used for enrichment of PHA storing organisms.
• Reducing the cycle length enhanced PHA production.
• Enhanced waste remediation with simultaneous value addition was achieved.

Polyhydroxyalkanoates (PHA) production was evaluated in a multistage operation using food waste as a renewable feedstock. The first step involved the production of bio-hydrogen (bio-H2) via acidogenic fermentation. Volatile fatty acid (VFA) rich effluent from bio-H2 reactor was subsequently used for PHA production, which was carried out in two stages, Stage II (culture enrichment) and Stage III (PHA production). PHA-storing microorganisms were enriched in a sequencing batch reactor (SBR), operated at two different cycle lengths (CL-24; CL-12). Higher polymer recovery as well as VFA removal was achieved in CL-12 operation both in Stage II (16.3% dry cell weight (DCW); VFA removal, 84%) and Stage III (23.7% DCW; VFA removal, 88%). The PHA obtained was a co-polymer [P(3HB-co-3HV)] of PHB and PHV. The results obtained indicate that this integrated multistage process offers new opportunities to further leverage large scale PHA production with simultaneous waste remediation in the framework of biorefinery.

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