Elucidating the enzymatic response of the white rot basidiomycete Abortiporus biennis for the downgrade of polystyrene

Plastic pollution is a growing global environmental concern, with polyolefins such as polyethylene and polypropylene, as well as polystyrene (PS) constituting a significant amount of plastic waste. Both polyolefins and PS, when inappropriately disposed of in the environment, contribute to environmental contamination since they degrade slowly, with both abiotic and biotic factors contributing to their downgrade. In terms of the microbial effect on plastics, in recent decades, several studies have focused on the biodeterioration and assimilation of polyolefins, while more comprehensive degradation of PS by diverse organisms, including bacteria, fungi, and even insect larvae, has been documented. The present study investigates the biocatalytic potential of the white-rot basidiomycete Abortiporus biennis LGAM 436 for PS degradation. Building on prior research, we examined the ability of this fungal strain to modify the structure of different PS forms, including commercial expanded polystyrene (EPS) foam and amorphous PS film. In addition, we explored the impact of olive oil mill wastewater (OOMW) effluent as an enzymatic inducer to enhance the degradation process. Through gel permeation chromatography (GPC), surface morphology changes, and FTIR-ATR analysis, we assessed the extent of PS degradation and identified relevant enzymatic activities via proteomics. The findings offer insights into the discovery of novel fungal biocatalysts for addressing plastic pollution, particularly through the action of high-redox oxidative enzymes.