Classification of the biphenyl- and polychlorinated biphenyl-degrading strain LB400T and relatives as Burkholderia xenovorans sp. nov.

Abstract

Strain LB400T is the best-studied polychlorinated biphenyl (PCB) degrader. This organism has previously been allocated in the genus Burkholderia, since its 16S rRNA gene sequence shows 98·6 % sequence similarity to the type strains of Burkholderia graminis and Burkholderia terricola. A polyphasic study was undertaken to clarify the actual taxonomic position of this biotechnologically important organism and of two strains, one recovered from a blood culture vial and one from a coffee plant rhizosphere, both of which resembled strain LB400T in their whole-cell protein patterns. DNA–DNA hybridization experiments revealed that the three strains represented a single novel species, for which the name Burkholderia xenovorans sp. nov. is proposed. Strains of this novel species can be differentiated phenotypically from nearly all other Burkholderia species by their inability to assimilate l-arabinose. The whole-cell fatty acid profile of B. xenovorans strains is consistent with their classification in the genus Burkholderia, with 18 : 1ω7c, 16 : 1ω7c, 16 : 0, 14 : 0 3OH, 16 : 0 3OH, 17 : 0 cyclo and 14 : 0 being the most abundant fatty acids. The G+C content of the species varies between 62·4 and 62·9 mol%. The type strain of B. xenovorans is LB400T (=LMG 21463T=CCUG 46959T=NRRL B-18064T).