Polyhydroxyalkanoates: Biosynthesis from Alternative Carbon Sources and Analytic Methods: A Short Review

In recent decades, the global accumulation of plastics and the resulting pollution, as well as the increase in the price of oil, have driven studies aimed at the production of biodegradable plastics and the use of renewable carbon sources for their synthesis. In this context, the poly(hydroxyalkanoate) (PHA) biopolymers are highlighted as a class type of microbial polyester produced by fermentation of carbon substrates and stored in the form of granules in the bacterial cytoplasm. The scientific-industrial prominence of PHAs is due to their characteristics, such as thermoplasticity, biodegradable, non-toxicity, and biocompatibility. This versatility makes these biopolymers potential candidates for industrial, pharmaceutical, biomedical and food packaging applications. Despite these advantages, the commercialization of PHA on a large scale is restricted by its high production cost compared to petroleum-based plastics. The high cost is mainly attributed to the carbon source used in the fermentation processes, representing approximately 50% of the total production costs. Thereby, studies have focused on prospecting alternative carbon sources, such as agro-industrial residues to reduce the production cost to make PHAs more commercially competitive. In this regard, this review presents an overview of poly(hydroxyalkanoates), addressing alternative carbon sources as substrates for their synthesis, description of analytical and extraction methods applied to recover and characterize this biopolymer.