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Biodegradation of thermo-oxidative pretreated low-density polyethylene (LDPE) and polyvinyl chloride (PVC) microplastics by Achromobacter denitrificans Ebl13

Marine Pollution Bulletin 2022 76 citations ? Citation count from OpenAlex, updated daily. May differ slightly from the publisher's own count.
Mojtaba Maleki Rad, Hamid Moghimi, Ehsan Azin

Summary

This study examined the toxic effects of combined polystyrene microplastic and copper exposure on the freshwater algae Scenedesmus obliquus, finding synergistic growth inhibition and increased oxidative stress compared to single-contaminant exposures. Microplastics enhanced copper uptake by cells.

Microplastics pretreatment of prior to biodegradation is an efficient approach for their bioremediation. We isolated Achromobacter denitrificans from compost and used it for biodegradation of thermo-oxidative pretreated polyvinyl chloride (PVC) and low-density polyethylene (LDPE). About 12.3 % and 6.5 % weight loss, and 326.4 and 112.32 mg L extracellular protein were observed in bacterial flasks with PVC and LDPE, respectively. The pH in treated PVC reached to 5.12 and the thermal stability increased by 29 °C. The chemical modification in LDPE was demonstrated through oxidation of antioxidants (Phenol group), formation of new groups (Aldehyde group), and chain fracture in the main backbone by Fourier transform infrared spectroscopy. Formation of peaks at the range of 1700-1850 cm in LDPE attributed to formation of carbonyl groups as the degradation result. Scanning electron microscopy confirmed LDPE and PVC degradation by surface alterations. Consequently, thermo-oxidative pretreatment can be considered as a suitable strategy for improving microplastics biodegradation.

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