Trends and challenges in the valorization of kitchen waste to polyhydroxyalkanoates

Kitchen waste (KW) is frequently available for free or with a negative cost due to its huge production. It contains a large proportion of organic substances, especially fermentable sugars, which can be used for bioplastic (polyhydroxyalkanoates or PHA) synthesis. Nevertheless, due to the difficulties in processing, various pre-treatments of KW are being investigated to enhance the concentration of simple sugars released during its hydrolysis. The effective use of KW will help in minimizing the issues of its inappropriate disposal. However, the review on KW to bioplastic synthesis is rarely reported in the literature. Hence, this particular review provides a comprehensive summary of the updated research developments in KW valorization and its potency as a feedstock for PHAs synthesis. Additionally, the impacts of KW, its availability, the necessary pre-treatments for the biopolymerization process, as well as the prospects and challenges for industrially generating sustainable PHAs, are critically discussed.