EVALUATION OF PET SHEET DEGRADATION USING THERMOPHILIC GEOBACILLUS SP. PT206

Abstract

This research aimed to evaluate the degradation of Polyethylene terephthalate (PET) sheet using the thermophilic Geobacillus sp. PT206 isolated from the landfill site at Saraburi province. Strain PT206 gave the highest Hydrolytic Capacity on MSM with BHET, at 29.1 ± 14.0. PET degradation was evaluated in biometer flasks containing Bushnell Haas Broth with PT206 at 55°C for 1 month. Optical density was measured every 7 days to monitor the bacterial growth, and carbon dioxide evolution was performed in three conditions: PT206 with PET, Control without PT206, and Control without PET. During incubation, the bacteria were able to grow, and the cumulative carbon dioxide increased. However, these changes were not significantly different from the control. The water contact angle of the treated plastic decreased from 67.12 ± 1.02° to 61.19 ± 3.31°. Furthermore, the infrared spectrum revealed a change in all PET peaks in the plastic incubated with bacteria and SEM showed abundant biofilm on the treated plastic surface, which was not observed in the control. These results indicate that the incubation of PT206 with PET for 1 month led to changes in the PET surface.