Isolation of a polyethylene-degrading bacterium, Acinetobacter guillouiae, using a novel screening method based on a redox indicator

Abstract

Plastic, a polymer synthesized from petrochemicals, is used worldwide. However, natural degradation of plastic is difficult, causing environmental pollution, with microplastics posing a serious threat to human health. In this study, we aimed to use a new screening method based on the oxidation-reduction indicator, 2,6-dichlorophenolindophenol, to isolate a polyethylene-degrading bacterium, <i>Acinetobacter guillouiae</i>, from insect larvae. Plastic-degrading strains are identified by the color change in the redox indicator from blue to colorless as plastic metabolism occurs. Polyethylene biodegradation by <i>A. guillouiae</i> was verified through weight loss, surface erosion, physiological evidence, and chemical changes on the plastic surface. In addition, we analyzed the characteristics of hydrocarbon metabolism in polyethylene-degrading bacteria. Results suggested that alkane hydroxylation and alcohol dehydrogenation were key steps in polyethylene degradation. This novel screening method will pave the way for high-throughput screening of polyethylene-degrading microorganisms and extending its application to other types of plastics may potentially address plastic pollution.