Technological watch

Polybutylene succinate (PBS) is a bioplastic substitute for synthetic plastics that are made from petroleum-based products such as polyethylene and polypropylene. However, the biodegradation rate of PBS is still low and similar to that of polylactic acid (PLA). Moreover, our knowledge about degrader species is limited to a few fungi and mixed consortia. Here, to identify a bacterial degrader to accelerate PBS degradation, we screened and isolated Terribacillus sp. JY49, which showed significant degradability. In order to optimize solid and liquid culture conditions, the effect of factors such as temperature, additional carbon sources, and salt concentrations on degradation was confirmed. We observed a degradation yield of 22.3% after 7 days when adding 1% of glucose. Additionally, NaCl was added to liquid media, and degradation yield was decreased but PBS films were broken into pieces. Comparing the degree of PBS degradation during 10 days, the degradation yield was 31.4% after 10 days at 30 °C. Alteration of physical properties of films was analyzed by using scanning electron microscopy (SEM), gel permeation chromatography (GPC), and Fourier transform infrared (FT-IR). In addition, Terribacillus sp. JY49 showed clear zones on poly(butylene adipate-co-terephthalate) (PBAT), polycaprolactone (PCL), and copolymers such as P(3HB-co-3HV) and P(3HV-co-4HB), exhibiting a broad spectrum of degradation activities on bioplastics. However, there was no significant difference in absorbance when esterase activity was examined for different types of bioplastics. Overall, Terribacillus sp. JY49 is a potential bacterial strain that can degrade PBS and other bioplastics, and this is the first report of Terribacillus sp. as a bioplastic degrader.