Polyhydroxyalkanoates (PHAs) are promising biodegradable plastics that can provide an approach to solve plastic pollution in the future. The biggest challenge of PHAs usage is the high cost of production. To address this problem, cheap substrates and a simple operation process are the priority. Various waste feedstocks provide enough low-cost carbon sources to obtain sustainable PHAs production. Numerous microbes have the capability of PHAs accumulation and degradation. Experiments with mixed microbial cultures and extremophiles demonstrated successful PHAs production. Up to now, scientists have extensively studied the mechanism of PHAs production and degradation. The fundamental parameters have been studied to engineer a path for up-scaling production. Many applications have been performed using different types of PHAs. The properties of PHAs have been characterized to better understand the performances of PHAs to meet further design an industrial demand plastic.