Four novel Arthrobacter species isolated from filtration substrate

1 Hirose Laboratory Environmental Microorganism, Honcho, Funabashi-City, Chiba Pref. 4-43-20, Japan 2 Laboratory of Bioresources, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan Correspondence Linxian Ding dinglinxian{at}hotmail.com Four Gram-positive, non-motile, non-spore-forming bacterial strains, LC4 T , LC6 T , LC10 T and LC13 T , were isolated from a filtration substrate made from trass, a volcanic rock, and their taxonomic positions were investigated by a polyphasic taxonomic approach. The novel strains grew over a temperature range of 5–40 °C, at pH values of 6–11 and in the presence of 3–7 % (w/v) NaCl. A phylogenetic tree based on 16S rRNA gene sequences showed the novel strains formed a distinct evolutionary lineage within the genus Arthrobacter . Chemotaxonomic analyses demonstrated that the major menaquinone was MK-9(H 2 ), a menaquinone typical of the Arthrobacter globiformis group. The major fatty acid was anteiso-C 15 : 0 and the major amino acid present in the cell-wall peptidoglycan was L -lysine. These observations supported the affiliation of the novel strains to the genus Arthrobacter . On the basis of their morphological, physiological and genotypic characteristics, the new isolates are considered to represent four novel species of the genus Arthrobacter , for which the names Arthrobacter niigatensis sp. nov. (type strain LC4 T =IAM 15382 T =CCTCC AB 206012 T ), Arthrobacter alkaliphilus sp. nov. (type strain LC6 T =IAM 15383 T =CCTCC AB 206013 T ), Arthrobacter echigonensis sp. nov. (type strain LC10 T =IAM 15385 T =CCTCC AB 206017 T ) and Arthrobacter albidus sp. nov. (type strain LC13 T =IAM 15386 T =CCTCC AB 206018 T ) are proposed. The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequences of Arthrobacter niigatensis LC4 T , Arthrobacter alkaliphilus LC6 T , Arthrobacter echigonensis LC10 T and Arthrobacter albidus LC13 T reported in this paper are AB248526 , AB248527 , AB248531 and AB248533 , respectively.