Microbial-mediated biodegradation of polyethylene terephthalate (PET) by marine bacterial isolates: A sustainable...

The current research focuses on the biodegradation of PET plastic by marine bacteria isolated from Arabian Sea. Each purified strain was subjected to PET biodegradation profiling in order to select most potent PET degrading bacteria. On the basis of weight loss method (%), two efficient marine strains were chosen and subjected to ribotyping and optimization studies via OFAT approach. For further evaluation of PET degradation, FTIR and SEM analysis were carried out. The two efficient PET bio-degraders were identified as Bacillus subtilis MPW7 and Priestia endopytica MPW8. The optimum temperature for PET degradation was 35 °C, at which Bacillus subtilis MPW7 and Priestia endophytica MPW8 achieved PET weight losses of 10.7 1 ± 0.23% and 12.09 ± 0.045%, respectively. The optimum pH was 6.5, under which Bacillus subtilis MPW7 exhibited a PET weight loss of 21 ± 0.89%, while Priestia endophytica MPW8 achieved the highest degradation efficiency with a weight loss of 30 ± 1.0%. Qualitative screening of plastic degrading enzymes showed that both marine bacteria are lipase, esterase, protease and peroxidase producers. FTIR spectral studies confirmed the PET biodegradation by selected isolates. Modifications in the structural configuration of PET plastic after bio-treatment were also noticed through SEM.