1Department of Marine science, Tokyo University of Marine Science and Technology, Minato, Tokyo 108-8477, 2Toyama Fisheries Experiment Station, Namerikawa, Toyama 936-8536, 3Projec Planning Department Fisheries Research Agency, Yokohama, Kanagawa 220-6115, Japan
Biodegradabilities of aliphatic polyester fibers and natural fibers were evaluated in deep sea water at the depth of about 2000 m offshore of Tottori Prefecture and deep sea water pumped up from the depth of 321 m at 2600 m offshore in Toyama bay. The breaking strengths of all soaked fibers decreased considerably in one year. On the surfaces of the soaked fibers, hollows engraved by biodegradation were observed. These results confirm that biodegradation takes place in the deep sea and in deep ocean water. Two kinds of PCL-degrading bacteria were isolated from the deep sea water. The phylogenetic analysis using the 16S rRNA gene sequence revealed that these strains belong to the Pseudomonas genus. The isolated bacteria showed growth and PCL degradation activity under low-temperature conditions.