title: Degradation of the cyanobacterial hepatotoxin microcystin by a new bacterium isolated from a hypertrophic lake.
abstract: A bacterium capable of degrading microcystins-RR, -YR, and -LR was isolated from a hypertrophic lake. The bacterium, designated Y2 and classified phenotypically as a member of the genus Sphingomonas, was shown to be distinct phylogenetically from any established species of Sphingomonas on the basis of 16S rDNA sequencing. The bacterium was tentatively identified as Sphingomonas by manual chemotaxonomy, but 16S rRNA sequencing analysis suggests that it is in fact a new species or even a new genus. When the Y2 bacterium was added to microcystins present in culture medium, the microcystins were degraded thoroughly in 4 days. The highest degradation rates of microcystins-RR and -LR were 13 and 5.4 mg L-1 day-1, respectively. The degradation rates were strongly dependent on temperature and the maximum rate was at 30 degrees C.
authors.affiliation: Department of Environmental Sciences, Faculty of Science, Shinshu University, Matsumoto 390-8621, Japan. pparkhd@gipac.shinshu-u.ac.jp
authors.forename: H D
authors.initials: HD
authors.lastname: Park
authors.forename: Y
authors.initials: Y
authors.lastname: Sasaki
authors.forename: T
authors.initials: T
authors.lastname: Maruyama
authors.forename: E
authors.initials: E
authors.lastname: Yanagisawa
authors.forename: A
authors.initials: A
authors.lastname: Hiraishi
authors.forename: K
authors.initials: K
authors.lastname: Kato
mesh_terms: D001673:Biodegradation, Environmental; D008387:Marine Toxins; D052998:Microcystins; D010456:Peptides, Cyclic / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S; D017422:Sequence Analysis, DNA; D020578:Sphingomonas / Q000235:genetics* / Q000302:isolation & purification; D013696:Temperature; D014871:Water Microbiology
chemical_list: D008387:Marine Toxins; D052998:Microcystins; D010456:Peptides, Cyclic; D012336:RNA, Ribosomal, 16S; C065685:microcystin YR; C063855:microcystin RR; C057862:cyanoginosin LR