Tropicibacter phthalicus sp. nov., A Phthalate-Degrading Bacterium from Seawater

Abstract

An aerobic, Gram-negative bacterial strain, designated KU27E1(T), which degrades phthalate and dimethylphthalate, was isolated from seawater obtained from the coastal region of Ishigaki Island, Japan. Cells are motile rods with polar flagella. Strain KU27E1(T) grew at 15-30°C, pH 6.0-8.0, in the presence of 1.0-2.0% (w/v) NaCl. The 16S rRNA gene sequence analysis revealed that this strain was affiliated with the family Rhodobacteraceae in the class Alphaproteobacteria, and was most closely related to Tropicibacter naphthalenivorans (96.8%). The predominant respiratory lipoquinone was ubiquinone-10, and the major cellular fatty acid was C(18:1)ω7c (88.5%). The G+C content of genomic DNA was 58.7 mol%. Based on the physiological, chemotaxonomic, and phylogenetic data, strain KU27E1(T) is suggested to represent a novel species of the genus Tropicibacter, for which the name Tropicibacter phthalicus sp. nov. is proposed. The type strain of Tropicibacter phthalicus is designated as KU27E1(T) (=JCM 17793(T) = KCTC 23703(T)).

Phthalate Release from Plastic Fragments and Degradation in Seawater

“…Additionally, the difference in the prokaryotic degradation is very likely the result of the specific abundance of the organisms with the specific ability to degrade individual PAEs. , Note that the DEHP and DnBP biodegradation by pure cultures of bacteria isolated from activated sludge, mangrove sediments, and wastewater have been already reported, − whereas several microorganisms were identified for phthalate degradation, such as Pseudomonas fluorescens , Rhodococcus rhodochrous , and Comamonas acidovoran. − The already published DnBP degradation rate and half-life of the isolated bacteria ranged from 0.018 to 0.035 h –1 and from 20 to 72 h, respectively. ,, However, most of the microorganisms have been isolated from terrestrial subsurface environments, and far less is known about their counterparts in marine environments. In addition, complete phthalate degradation is always carried out syntrophically by several members of microorganisms in natural environments .…”