Identification of a poly(3-hydroxybutyrate)-degrading bacterium isolated from coastal seawater in Japan as Shewanella sp

• Published in: Polymer degradation and stability 2016-07, Vol.129, p.268-274
• Main Authors: Sung, Chun-Che, Tachibana, Yuya, Suzuki, Miwa, Hsieh, Wen-Chuan, Kasuya, Ken-ichi
• Format: Article
• Language: English
• Subjects: (PHB)-degrading bacterium; Bacteria; Biodegradable plastics; Carbon; Degradation; Marine bacterium; Marine environment; Marine environments; Optimization; Poly[(R)-3-hydroxybutyrate]; Ports; Sea water; Shewanella; Shewanella sp; Sole
• ISSN: 0141-3910; 1873-2321
• DOI: 10.1016/j.polymdegradstab.2016.05.008

A poly[(R)-3-hydroxybutyrate] [P(3HB)]-degrading bacterium (strain JKCM-AJ-6,1α) was isolated from coastal seawater near the port of Yaizu, Suruga Bay, Japan. The strain grew well in a marine mineral medium supplemented with P(3HB) powder as the sole carbon source. Phylogenetic analysis revealed that the strain JKCM-AJ-6,1α belonged to the genus Shewanella. The isolate was unable to grow at temperatures above 50 °C, and the optimum range of growth temperatures was 30 °C–37 °C; however, the optimum temperature for degradation of P(3HB) was 15 °C. The maximum specific growth rate (μ = 1.0 h−1) was attained at a NaCl concentration of 0.2 M, but the strain was able to grow even in the presence of 0.8 M NaCl. This suggests that the strain is a typical marine bacterium. This is the first report showing P(3HB) depolymerase activity in a member of the genus Shewanella. It is concluded that the genus Shewanella may be one of the key bacterial groups involved in the P(3HB) cycle in marine environments.