Diversity of Polyester Degrading Bacteria in Surface Sediments from Yangtze River Estuary

In order to preliminarily understand the diversity of degradable polyester-synthesizing strains in the adjacent waters of the Yangtze Estuary, solid media containing polycaprolactone (PCL) and tributyrin were used to screen strains with PCL and Tributyrin-degrading activity from the surface sediments of the adjacent waters of the Yangtze Estuary at different times by transparent circle method. In this study, 480 strains with PCL or Tributyrin degradation activity were obtained, of which 445 strains could simultaneously degrade PCL and Tributyrin, only 34 strains could degrade Tributyrin, only 1 strain could degrade PCL, accounting for 92.71%, 7.08% and 0.22% of the total number of strains, respectively. Classification studies showed that these strains belonged to 50 species of 14 genera. The dominant strains of degradable PCL and Tributyrin obtained in February, May, July and September were Psychrobacter, Bacillus, Vibrio and Vibrio, respectively. Vibrio appeared in May, July and September, especially in July. Diversity index analysis showed that the biodiversity of synthetic polyester-degrading bacteria in surface sediments of the Yangtze Estuary was higher than that of PCL-degrading bacteria in May > February > September > July, and that of Tributyrin-degrading bacteria was higher than that of PCL-degrading bacteria. The results show that PCL and Tributyrin degrading bacteria are abundant in the surface sediments of the Yangtze Estuary and play an important role in plastic biodegradation in this area.