Polypropylene waste valorization using microbes for sustainable development

Abstract

Polypropylene (PP) which comes in both low and high densities is one of the most widely used polymers (18.85%). PP is extensively used in various industries but poses environmental threats due to its resistance to recycling and slow biodegradation. To address this, innovative methods for conversion of PP waste into beneficial products and energy are necessary. "Polypropylene waste valorization" encompasses advanced techniques like microbial degradation, chemical recycling, photocatalysis, and pyrolysis, along with mechanical recycling. While only a few microbes have been identified for PP breakdown whereas pyrolysis produces valuable liquid fuel. Only a small number of microbes, including Rhodococcus sp., Phanerochaete chrysoporium, Bacillus sp., and Brevibacillus sp., have been documented to breakdown PP. PP pyrolysis leads to a liquid product known as “pyrolysis oil” that is used as an alternative fuel for various applications. The environmental impact of producing PP is reduced by reducing plastic waste through effective valorization methods. The production of secondary materials or chemicals from PP trash also helps to save resources, save energy, and lessen reliance on fossil fuels. These valorization methods reduce environmental impact, conserve resources, and potentially create jobs. However, challenges like low conversion rates and catalyst deactivation persist. This review focuses on comprehensive research into PP valorization by bacteria and fungi, including pre-treatment methods like ultraviolet radiation and varying environmental conditions.