DESCRIPTION OF CHLOROPHENOL-DEGRADING PSEUDOMONAS SP STRAINS KF1(T), KF3, AND NKF1 AS A NEW SPECIES OF THE GENUS SPHINGOMONAS, SPHINGOMONAS-SUBARCTICA SP-NOV

Gram-negative polychlorophenol-degrading bacterial strains KF1(T) (T = type strain), KF3, and NKF1, which were described previously as Pseud omonas saccharophila strains, were studied by chemotaxonomic, genetic, and physiological methods acid by electron microscopy and compared wi th selected xenobiotic compound-degrading bacteria. These strains cont ained sphingolipids with d-18:0, d-20:1, and d-21:1 as the main dihydr osphingosines, ubiquinone 10 as the main respiratory quinone, and sper midine as the major polyamine, and the DNA G+C content was 66 mol%. Th e cellular fatty acids included about 60% octadecenoic acid, 9% 2-hydr oxymyristic acid, 14% cis-9-hexadecenoic acid, and 10% hexadecanoic ac id. These strains exhibited less than 97% 16S ribosomal DNA sequence s imilarity to all of the other taxa studied, In the DNA-DNA reassociati on studies the highest levels of reassociation between these strains a nd previously described species were less than 40%. Thin sections of c ells of strains KF1(T), KF3, and NKF1 were examined by electron micros copy, and the results showed that the cells had peculiar concentricall y arranged layered membranous blebs that extruded from the outer membr ane, especially at the cell division points, On the basis of the resul ts of this study, polychlorophenol-degrading strains KF1(T), KF3, and NKF1 are considered members of a new species of the genus Sphingomonas , Sphingomonas subarctica. The polycyclic aromatic hydrocarbon-degradi ng organism Sphingomonas paucinobilis EPA 505 was closely related to S phingomonas chlorophenolica as determined by chemotaxonomic, phylogene tic, and physiological criteria, The xenobiotic compound degraders Alc aligenes sp, strain A175 and Pseudomonas sp. strain BN6 were identifie d as members of species of the genus Sphingomonas.