| More evidences suggest that microbes participate in the geochemical circulation of metal(loid)s, and play an important role in the biocirculation. Soil metal(loid) contamination is very serious, particularly in mining areas. As the major sources of pollution, arsenic and antimony were given increasing attentions by the environmental protection department. Thus remediation soils contaminated by metal(loid)s has become very necessary. Microbial populations in mining soil play an important role in the formation of pollution, transformation and ecological restoration. In this study, we analyzed the microbial species and diversity of arsenite[As(III)]-resistant bacteria and antimony[Sb(III)]-resistant bacteria from soils of Daye iron mine (Hubei) and Jixi coal mine (Heilongjiang). The results revealed that the arsenite-resistant and antimony-resistant bacteria types from both the soils were similar, but each soil had its distinctive species. A total of 16 arsenite-resistant bacteria and 12 antimony-resistant bacteria were identified from both the soils, and 8 arsenite-resistant bacteria and 6 arsenite-resistant bacteria were isolated from Daye iron mine, the other were from Jixi coal mine. Phylogenetic analyses based on 16S rRNA gene sequences indicated that Bacillus, Comamonas and Pseudomonas were both found from Daye iron mine and Jixi coal mine soil, while Achromobacter, Ensifer and Skermanella were identified from Jixi coal mine soil. Study of microbial diversity of the arsenite-resistant and antimony-resisitent bacteria in the mining area provides important information that is useful for mining area ecology and for application of microbial remediation of the soil contaminated by metal(loid)s.A Gram-negative, aerobic, high arsenite-resistant bacterium, designated strain ZS79T, was isolated from subsurface soil of Daye iron mine, in China. The isolate grew at NaCl concentration within the range 0-4%, temperatures from 4 to 37℃(optimum 28℃) and within a pH range 5-9 (optimum 7.0). Cells of strain ZS79T are motile, rod shaped. The genomic DNA G+C content was 70.7 mol%. The isoprenoid quinone was Q-8. The major fatty acids were iso-C15：0, iso-Ci17:1ω9c, iso-C16:0, iso-C11:0 and iso-C11:0 3-OH. Polar lipids found in strain ZS79T were PG, DPG, PE and PME. Phylogenetic analysis based on 16S rRNA gene sequence analysis indicated that strain ZS79T was closely related to the type strains of Lysobacter species with 92.7%-96.9% sequence similarities. On the basis of morphological, physiological/biochemical characteristics, phylogenetic position and chemotaxonomic data, this strain is considered as a novel species of Lysobacter, for which the name Lysobacter arseniciresistens sp. nov. is proposed. The type strain is ZS79T (= CGMCC 1.10752T= KCTC 23365T).A Gram-negative, aerobic, motile, rod-shaped, antimony-resistant bacterium, designated strain SB22T, was isolated from soil of Jixi coal mine, China. The isolate grew at NaCl concentration within the range 0-4%(optimum 0%), temperatures from 4 to 37℃(optimum 28℃) and within a pH range 5-9 (optimum 7.0). The major cellular fatty acids were C18:1ω7c, summed feature 2 and C16:0.The major polar lipids were DPG, PC, PE and PG. 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 SB22T was most closely related to Skermanella aerolata 5416T-32T(97.3%), Skermanella parooensis ACM 2042T (95.8%) and Skermanella xinjiangensis 10-1-101T (92.9%). DNA-DNA hybridization value between strain SB22T and S. aerolata 5416T-32T was 43.3%. On the basis of phenotypic, chemotaxonomic and phylogenetic characters among strain SB22T and the related species revealed that the isolate is considered as a novel species of Skermanella, for which the name Skermanella stibiiresistens sp. nov. is proposed. The type strain is SB22T (= CGMCC 1.10751T= KCTC 23364T).In this study, we analyzed the microbial species and diversity of arsenite-resistant bacteria and antimony-resistant bacteria from soils of Daye iron mine and Jixi coal mine. We also identified two new bacteria ZS79 and SB22 and performedpolyphasic taxomony analyses. The resistant level for arsenite and antinomy for strain ZS79 and SB22, respectively, are much higher than the other type strains in the same genus. In addition, we analyzed the polar lipids of all type strains of the genus Skermanella and emended the genus description. This study identified novel bacterial species and enriched the bacterial resounces of mining soil environemts. |
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