Abstract
Plastic waste has become one of the most pressing environmental issues with rapidly increased their production that also has a severe impact on individual species and ecosystem functioning.

With recycling technologies in place, the waste plastic will become a valuable resource and hence less material will be lost to the environment. In the pursuit of a sustainable approach to the treatment of plastic waste, biological processes have emerged as an eco-friendly method with significant potential. In this review, we summarize previous research on the biodegradation of polystyrene (PS) as major plastics, including a review of the analytical methods used to investigate the plastic biodegradation, the isolation of PS-degrading microbes from various environment, and the identification of potential enzymes for PS biodegradation. Based on this, we propose a potential PS biodegradation pathway, even though the specific biochemical mechanisms associated with certain enzymes have not yet been fully identified. Finally, we discuss how PS-biodegrading enzymes can be identified using a systems biology-based screening approach that combines culture-based genomic and culture-independent metagenomic methods. This strategy can be applied to searching biodegrading enzymes for other plastics.