Biodegradation of synthetic surfactants: linear alkylbenzenesulfonates (LAS) and related compounds

Strain DS-1 is a small (0.8 μm in length and 0.2 μm in diameter) heterotrophic member of the α-Proteobacteria able to ω-oxygenate the commercial surfactant linear alkylbenzenesulfonate (LAS) and shorten the sidechain by β-oxidation to yield sulfophenylcarboxylates. The morphotype is widespread in cultures able to utilise LAS, and a second organism with similar characteristics, strain AN-8, is now available. Utilisation of LAS is concomitant with formation of a biofilm, and cells are non-motile. Many surfactants were utilised. The organisms also grew with acetate or octane, but required no biofilm and were motile. Analysis of the gene encoding 16S rRNA placed the organisms in the α-subclass of Proteobacteria with a sequence divergence of > 8 % from any species whose name has been validly published. 16S rDNA sequence comparison to entries in the GenBank database showed 98 % similarity to an α-protobacterial marine isolate JP57: strain JP57 displayed the same morphotype as strain DS-1, but it was unable to utilise surfactants or any single source of carbon tested. The lipid components of strains DS-1 and JP57 were virtually identical. The fatty acids contained esterand putative amide-linked hydroxy fatty acids, in a combination which is currently unique in the αProteobacteria. The major respiratory quinone present in both strains was ubiquinone 11 (Q11) and the polar lipids consisted of phosphatidyl glycerol, diphosphatidyl glycerol, phosphatidyl ethanolamine, phosphatidyl choline and two unidentified aminolipids. Data on the 16S rRNA gene sequence and the lipid composition indicated that strains DS-1 and JP57 should be placed in a new genus, for which we propose the name Parvibaculum. The differences between these strains, supported by DNA hybridisations, lead us to conclude that strain DS-1 (= DSM 13023 = NCIMB 13966) is the type strain of a species in the genus Parvibaculum, for which the name Parvibaculum lavamentivorans is proposed.