Arsenic-resistant Pseudomonas spp. and Bacillus sp. bacterial strains reducing As(V) to As(III), isolated from Alps soils, Italy

Abstract

Five arsenic-resistant bacterial strains (designated MP1400, MP1400a, MP1400d, APSLA3, and BPSLA3) were isolated from soils collected at the Alps region (Italy), which showed no contamination by arsenic. Phylogenetic analysis of the 16S rRNA gene sequences assigned them to the genera Pseudomonas and Bacillus. Bacillus sp. strain 1400d and Pseudomonas spp. strains APSLA3 and MP1400 showed higher tolerance to As(III), as indicated by minimum inhibitory concentrations of 10 mmol/L. Pseudomonas sp. strain MP1400 exhibited higher tolerance to As(V) (minimum inhibitory concentration of 135 mmol/L). The isolated arsenic-resistant strains were able to reduce As(V) to As(III), especially Pseudomonas sp. strain MP1400 reducing 2 mmol/L of As(V) to As(III) within 24 h. The results suggest that the isolated bacterial strains play a role in the arsenic biogeochemical cycle of arsenic-poor soils in the Alps mount area.

Taxonomically-linked growth phenotypes during arsenic stress among arsenic resistant bacteria isolated from soils overlying the Centralia coal seam fire

“…We subsequently determined that, despite the fire activity at this particular site, the soil had relatively low As concentrations at the time of soil collection (2.58 ppm). This is not surprising, given that 1) the fire is dynamic and past As concentrations at the vent may have been higher given the natural occurrence of As as a byproduct of coal combustion [ 32 , 34 ] and 2) the widespread observation of microbial As resistance from soils that have generally low contamination [ 41 , 60 – 63 ]. While our isolation resulted in an abundance of Firmicutes, this is not surprising since members of phylum Firmicutes have been shown to be resistant to As previously with varied MICs [ 60 , 64 ].…”

“…Our results are consistent with previous reports that Proteobacteria often have high MICs ( Fig 2B ) [ 5 , 19 ]; however, when simultaneously analyzing reductions in growth with As, our results show distinct growth strategies among lineages, in both arsenate and arsenite ( Fig 4 and S3 Fig ). While other reports have examined growth reduction in the presence of As to find suitable strains for bioremediation [ 17 , 62 , 63 , 66 , 67 ], a suite of growth parameters are not typically investigated. Our full characterization of growth in increasing concentrations of As showed a modest relationship between growth phenotype and taxonomy and highlights discrepancies between fitness in As and MIC.…”

Vertical distribution of bacterial communities in high arsenic sediments of Hetao Plain, Inner Mongolia

“…Polaromonas, Paenibacillus and Flavobacterium, which were consistent with the DGGE and 16S clone library results. These populations were highly similar with those populations associated with denitrification, sulfur oxidation, organic matter degradation and As resistance and reduction (Achour et al 2007;Pepi et al 2011). For example, genus Acinetobacter could show exceptional As tolerance and Sporosarcina species could possess arsB and acr3 genes which are known for resistance to high concentrations of arsenite (Achour et al 2007).…”

“…Paenibacillus (28 % of total clones) and Polaromonas (15 % of total clones) were two dominant genera in the sediment sample, which were different from some other high As sediments where Thiobacillus was the most dominant genus Wang et al 2014). Paenibacillus and Pseudomonas showed high similarities with populations sensitive to the organic matter and heavy metal contaminants including As (Pepi et al 2011). Polaromonas was reported to be capable of the degradation of various pollutants (Yagi et al 2009).…”

The potential of Pseudomonas for bioremediation of oxyanions

“…fluorescens and P . putida , which showed a minimum inhibitory concentration of As(V) of more than 500 mM (Pepi et al ., 2011; Oller et al ., 2013).…”