Polyhydroxyalkanoates (PHAs) synthesis and degradation by microbes and applications towards a circular economy

Overusing non-degradable plastics causes a series of environmental issues, inferring a switch to biodegradable plastics. Polyhydroxyalkanoates (PHAs) are promising biodegradable plastics that can be produced by many microbes using various substrates from waste feedstock. However, the cost of PHAs production is higher compared to fossil-based plastics, impeding further industrial production and applications. To provide a guideline for reducing costs, the potential cheap waste feedstock for PHAs production have been summarized in this work. Besides, to increase the competitiveness of PHAs in the mainstream plastics economy, the influencing parameters of PHAs production have been discussed. The PHAs degradation has been reviewed related to the type of bacteria, their metabolic pathways/enzymes, and environmental conditions. Finally, the applications of PHAs in different fields have been presented and discussed to induce comprehension on the practical potentials of PHAs.