Biotechnological approaches: Degradation and valorization of waste plastic to promote the circular economy

The practical application of plastics is as indispensable as it is problematic regarding disposal. Plastics present significant opportunities in the context of circular usage and recycling. A circular economy dictates the utilization of every side stream to minimize waste. Current waste management techniques are insufficient in reducing plastic waste entering landfills, wastewater treatment systems, and the environment. Under these circumstances, plastic biodegradation has emerged as a viable and environmentally responsible approach to plastic pollution. Methods are needed for the natural degradation of plastics using microbes that can utilize plastics as their sole carbon source. Studies to enhance the catalytic activity of plastic-degrading enzymes through protein engineering approaches are a relatively new field of research. Enzymatic degradation for product creation represents a purely biological plastic recycling method in a sustainable economy. This review builds insights derived from previous studies and provides a brief overview of plastic degradation using enzymes, improvements in plastic-degrading enzyme efficiency, and stabilization via various protein engineering strategies. In addition, recent advances in plastic waste valorization technology based on systems metabolic engineering and future directions are discussed.