Antimony (Sb) and copper (Cu) are toxic heavy metals that are associated with a wide variety of minerals. Sb(III)-oxidizing bacteria that convert the toxic Sb(III) to the less toxic Sb(V) are potentially useful for environmental Sb bioremediation. A total of 125 culturable Sb(III)/Cu(II)-resistant bacteria from 11 different types of mining soils were isolated. Four strains identified as Arthrobacter, Acinetobacter and Janibacter exhibited notably high minimum inhibitory concentrations (MICs) for Sb(III) (>10 mM),making them the most highly Sb(III)-resistant bacteria to date. Thirty-six strains were able to oxidize Sb(III), including Pseudomonas-, Comamonas-, Acinetobacter-, Sphingopyxis-, Paracoccus- Aminobacter-, Arthrobacter-, Bacillus-, Janibacter- and Variovorax-like isolates. Canonical correspondence analysis (CCA) revealed that the soil concentrations of Sb and Cu were the most obvious environmental factors affecting the culturable bacterial population structures. Stepwise linear regression was used to create two predictive models for the correlation between soil characteristics and the bacterial Sb(III) or Cu(II) resistance. The concentrations of Sb and Cu in the soil was the significant factors affecting the bacterial Sb(III) resistance, whereas the concentrations of S and P in the soil greatly affected the bacterial Cu(II) resistance. The two stepwise linear regression models that we derived are as follows: and [where the MIC_Sb(III) and MIC_Cu(II) represent the average bacterial MIC for the metal of each soil (µM), and the C_Sb, C_Cu, C_S and C_P represent concentrations for Sb, Cu, S and P (mg/kg) in soil, respectively, p<0.01]. The stepwise linear regression models we developed suggest that metals as well as other soil physicochemical parameters can contribute to bacterial resistance to metals.

A Gram-negative, aerobic, motile, rod-shaped, arsenite [As(III)]-resistant bacterium, designated strain ZS79^T, was isolated from subsurface soil of an iron mine in China. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain ZS79^T clustered closely with strains of five Lysobacter species, with 96.9, 96.1, 96.0, 95.8 and 95.3 % sequence similarities to Lysobacter concretionis Ko07^T, L. daejeonensis GH1-9^T, L. defluvii IMMIB APB-9^T, L. spongiicola KMM 329^T and L. ruishenii CTN-1^T, respectively. The major cellular fatty acids were iso-C_15 : 0 (28.6 %), iso-C_17 : 1ω9c (19.9 %), iso-C_16 : 0 (13.6 %), iso-C_11 : 0 (12.6 %) and iso-C_11 : 0 3-OH (12.4 %). The genomic DNA G+C content was 70.7 mol% and the major respiratory quinone was Q-8. The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and an unknown phospholipid. On the basis of morphological and physiological/biochemical characteristics, phylogenetic position and chemotaxonomic data, this strain is considered to represent a novel species of the genus Lysobacter , for which the name Lysobacter arseniciresistens sp. nov. is proposed; the type strain is ZS79^T ( = CGMCC 1.10752^T = KCTC 23365^T).

A Gram-negative, aerobic, motile, rod-shaped, antimony-resistant bacterium, designated strain SB22^T, was isolated from soil of Jixi coal mine, China. The major cellular fatty acids (>5 %) were C_18 : 1ω7c (63.5 %), summed feature 2 (C_14 : 0 3-OH and/or iso-C_16 : 1 I, 10.8 %) and C_16 : 0 (9.9 %). The major polar lipids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol and an unknown aminolipid. The genomic DNA G+C content was 69.6 mol% and Q-10 was the major respiratory quinone. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain SB22^T was most closely related to Skermanella aerolata 5416T-32^T (97.3 %), Skermanella parooensis ACM 2042^T (95.8 %) and Skermanella xinjiangensis 10-1-101^T (92.9 %). The DNA–DNA hybridization value between strain SB22^T and S. aerolata KACC 11604^T ( = 5416T-32^T) was 43.3 %. On the basis of phenotypic, chemotaxonomic and phylogenetic characteristics of strain SB22^T and related species, it is considered that the isolate represents a novel species of the genus Skermanella , for which the name Skermanella stibiiresistens sp. nov. is proposed. The type strain is SB22^T ( = CGMCC 1.10751^T = KCTC 23364^T). An emended description of the genus Skermanella is provided.