PSEUDONOCARDIA ASACCHAROLYTICA SP. NOV. AND PSEUDONOCARDIA SULFIDOXYDANS SP. NOV., 2 NEW DIMETHYL DISULFIDE-DEGRADING ACTINOMYCETES AND EMENDED DESCRIPTION OF THE GENUS PSEUDONOCARDIA

Seven bacterial strains capable of oxidizing methyl sulfides were isol ated from experimental biofilters filled with tree-bark compost. The i solates could be divided into two groups according to their method of methyl sulfide degradation. Four isolates could use only dimethyl disu lfide as the sole source of energy and three strains were able to use dimethyl sulfide and dimethyl disulfide, Oxidation of the methyl sulfi des by both groups led to the stoichiometric formation of sulfate. Che motaxonomic, morphological, physiological and phylogenetic properties identified all isolates as members of the genus Pseudonocardia, The ab sence of phosphatidylcholine from the polar lipid pattern, as well as results of 16S rDNA analyses, led to the proposal of two new species, Pseudonocardia asaccharolytica sp, nov. and Pseudonocardia sulfidoxyda ns sp. nov. The type strains are P. asaccharolytica DSM 44247(T) and P . sulfidoxydans DSM 44248(T). With respect to the characteristic polar lipid pattern and the ability to oxidize sulfides, an emended descrip tion of the genus Pseudonocardia is proposed.