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A promising strategy to alleviate the plastic pollution from traditional petroleum‐based plastics is the application of biodegradable plastics, in which polyhydroxyalkanoates (PHAs) have received increasing interest owing to their considerable biodegradability. In the PHAs family, poly(3‐hydroxybutyrate‐co‐3‐hydroxvalerate) (PHBV) has better mechanical properties, which possesses broader application prospects. With this purpose, the present study adopted Cupriavidus necator to synthesize PHBV utilizing volatile fatty acids (VFAs) as sole carbon sources. Results showed that the concentration and composition of VFAs significantly influenced the production of PHAs. Especially, even carbon VFAs (acetate and butyrate) synthesized only poly(3‐hydroxybutyrate) (PHB), while the addition of odd carbon VFAs (propionate and valerate) resulted in PHBV production. The 3‐hydroxyvalerate (3HV) contents in PHBV were directly determined by the specific VFAs compositions, in which valerate was the preferred substrate for 3HV accumulation. After optimization by response surface methodology, the highest PHBV accumulation achieved 79.47% in dry cells, and the conversion efficiency of VFAs to PHBV reached 40%, with the PHBV production of 1.20 ± 0.05 g/L. This study revealed the metabolic rule of VFAs converting into PHAs by C. necator and figured out the optimal VFAs condition for PHBV accumulation, which provides a valuable reference for developing downstream strategies of PHBV production in industrial applications in future. [ABSTRACT FROM AUTHOR]

Vinegar residue (VR), a major by‐product in the vinegar brewing process, is generated at least three million tons annually in China. Currently major part of the disposal of VR is fulfilled by landfill and incineration, however, serious environment pollution along with such processes is a challenging issue. Anaerobic digestion (AD) can provide benefits of environment and renewable methane generation, which seems to be a reasonable alternative to traditional treatment. Noticeably, total solids (TS) is an important influential parameter to AD performance. Therefore, VR was evaluated for methane production and associated kinetic characteristics during the liquid‐state AD (LS‐AD) and solid‐state AD (SS‐AD) in this study. The results indicated that the highest specific methane yield of 194.8 mL gVS−1 and volumetric methane yield of 9.4 Lmethane Lreactor volume−1 were achieved in LS‐AD (TS = 10%) and SS‐AD (TS = 20%), respectively. The kinetic analysis showed a higher specific methane production rate for LS‐AD than SS‐AD, while volumetric methane production rate presented a reverse trend. This study provides useful guidance for the sustainable utilization of VR while contributes to environmental protection and alleviates the dependence on fossil fuels. [ABSTRACT FROM AUTHOR]

With the continuously increasing demands of plastic products in the current society, the challenge of disposing plastic waste is constantly increasing, leading to the urgent need of mitigating plastic pollution. As a consequence, much attention has been paid to biodegradable plastics due to their degradability in a bio-active environment under certain conditions. Biodegradable plastics herald vast development potentials and considerable market prospects. The degradation of numerous types of biodegradable plastics will be affected by many factors. A thorough understanding of degradation mechanisms as well as functional microbial strains and enzymes is the key to comprehensive utilization and efficient treatment and disposal of biodegradable plastics. The article summarized the types, properties, advantages and disadvantages, and main applications of common biodegradable plastics. The degradation mechanisms, functional microbial strains and enzymes, as well as the degradation degree and duration under different environmental conditions, were also summarized. This review may help better understand the degradation of biodegradable plastics wastes.