Valorization of poly-β-hydroxybutyrate (PHB)-based bioplastic waste in anaerobic digesters of food waste for bioenergy generation: reactor performance, microbial community analysis, and bioplastic biodegradation

This study aims to investigate the significance and biodegradation pathways of PHB-based bioplastic in anaerobic digesters treating food waste, where the reactor performance of changed methane generation, bioplastic biodegradation efficiency, and bioinformatic analysis of functional microbes were emphasized. The results showed that PHB-based plastic film could be partially biodegraded in the food waste digester, and a bioaugmentation use of Alcaligenes Faecalis (AF) and Bacillus Megaterium (BM) was beneficial to largely accelerate the degradation process through a beneficial shift of both the functional bacterial and archaeal species. Microbial community analysis indicated that the major bacterial species belonged to genera Candidatus_Cloacimonas, Rikenellaceae, and Defluviitoga, while the dominant methanogenic archaeal species belonged to genera Methanomassiliicoccus, Methanosarcina, and Methanosaeta. Bioplastic biodegradation analysis suggested that the optimal fractions of AF and BM for PHB-based plastic degradation were 50%AF and 75%BM, respectively, which deserves further optimization and scale-up validation. The finding of this study would contribute to the combined management of PHB-based bioplastic with food waste for clean energy recovery and a greener environment.