Degradation profiling of in-vitro-produced polyhydroxyalkanoate synthesized by the soil bacterium Bacillus sp. PhNs9 under different microenvironments

Abstract

Polyhydroxyalkanoates have been proven to be one of the best alternatives for synthetic plastics due to the similarity in their properties. The current study is focused on the natural degradation of the in vitro-produced PHA by the strain Bacillus sp. PhNs9. Different microenvironments were created to mimic different terrestrial and aqueous ecosystems. Maximum degradation of 98.62% was obtained in the soil while, in the case of aqueous systems, maximum degradation of 89.75% was found in the sewage wastewater in 30 days. The degradation profile of PHA was studied at different temperatures, pH, and moisture contents to ensure the degradation of produced PHA in different geographical locations having different environmental conditions. Different equations were obtained through a polynomial fitting for the prediction of degradation percentage at different conditions. The films were characterized using FTIR, Raman spectroscopy, drop shape analysis, and XRD which confirmed the decrease in both hydrophobicity and crystallinity of the films after degradation. This study established the natural degradation of the PHA produced by Bacillus sp. PhNs9 which could be commercialized without concerns about its accumulation in the environment.