New insights into the biodegradation of polylactic acid: from degradation to upcycling

Owing to its biosynthetic and biodegradable properties, polylactic acid (PLA) is considered to be a most promising biopolymer that could play a crucial role as a potentially environmentally friendly material for a sustainable bioeconomy. However, its long-life cycle indicates that it cannot be easily degraded in nature. Therefore, understanding the biodegradation mechanism of PLA is important for reducing the impacts of waste plastic and waste disposal. With the recent development of molecular biology techniques, some studies have confirmed that specific groups of microorganisms can facilitate the biodegradation of PLA. Here, recent advances in the biodegradation of PLA (i.e., microbial and enzymatic degradation) and key factors affecting the degradation efficiency were reviewed. In addition, compared with complete degradation through mineralization, upcycling is also proposed as a more recyclable strategy for disposing of waste plastics.