Microbial Degradation of High Impact Polystyrene (HIPS), an E-Plasticwith Decabromodiphenyl Oxide and Antimony Trioxide

Abstract

Accumulation of electronic waste has increased catastrophically and out of that various plastic resinsconstitute one of the leading thrown out materials in the electronic machinery. Enrichment medium,containing high impact polystyrene (HIPS) with decabromodiphenyl oxide and antimony trioxide assole carbon source, was used to isolate microbial cultures. The viability of these cultures in the e-plasticcontaining mineral medium was further confirmed by triphenyl tetrazolium chloride (TTC) reduction test.Four cultures were identified by 16S rRNA sequencing as Enterobacter sp., Citrobacter sedlakii, Alcaligenessp. and Brevundimonas diminuta. Biodegradation experiments were carried out in flask level and gelatinsupplementation (0.1% w/v) along with HIPS had increased the degradation rate to a maximum of 12.4%(w/w) within 30 days. This is the first report for this kind of material. The comparison of FTIR, NMR,and TGA analysis of original and degraded e-plastic films revealed structural changes under microbial treatment. Polystyrene degradation intermediates in the culture supernatant were also detected using HPLC analysis. The gravity of biodegradation was validated by morphological changes under scanning electron microscope. All isolates displayed depolymerase activity to substantiate enzymatic degradation of e-plastic.