Abstract:Some numerically dominant colonies, with creamy and nondiffusionable morphology, were isolated from lead-zinc tailings and their phylogenetic and physiological characteristics were determined. This type of colony represented approximate 50% of cultivable bacteria of tailings. Phylogenetic tree constructed from about 500 bp of 16S rRNA gene of 60 isolates and their relatives indicated that, these strains belonged to the member of Arthrobacter genus and were divided into several phylogenetically distinct groups. Three representatives from each group, BS11, BS20 and AS19, respectively, were sequenced approximate 1440 bp of 16S rRNA gene and their phylogeneic positions were further determined. Strain BS11 was phylogenetically close to A. histidinolovorans and A. nicotinovorans, BS20 close to A. chlorophenolicus, and AS19, to A. aurescens and A. ilicis. Among 39 carbon sources tested, three strains could strongly utilize 15 and weakly utilize 12 carbon sources. All of three strains showed high resistance to Pb(NO3)2, ZnSO4, CdCl2, CuSO4 and CoCl2, but relatively sensitive to ampicilin, streptomycin, kanamycin and rifimpicin. Our data suggested these strains may be potential novel species.
