Genomic Characterization of the Arsenic-Tolerant Actinobacterium, <i>Rhodococcus erythropolis</i> S43

Abstract

Rhodococcus erythropolis S43 is an actinobacterium isolated from an arsenic-contaminated soil sample, collected from an old smelter site, including an arsenic smelter, in Germany. This strain has unique features as compared to the other members of the species, namely resistance to elevated concentrations of arsenic. Here, we present the microbiological features and genomic properties of this biotechnologically relevant strain. The 6,812,940 bp draft genome is arranged into 264 scaffolds of 848 contigs. It possesses 62.5% of CG content and comprises 6,040 coding sequences and 49 tRNA genes. Bioinformatic genome analysis showed the presence of arsenic-resistance genes. A complete ars operon was found containing the arsACDR cluster coding for ArsA (efflux pump ATPase), ArsC (arsenate reductase), ArsD (chaperone) and ArsR (ars operon regulator). Our results show that the arsC mRNA level significantly increased in response to arsenite and arsenate exposure, suggesting its involvement in the arsenic resistance phenotype of strain S43. In addition, this strain showed to have a plethora of genes coding for proteins involved in oxidative-stress response, including catalase, super-oxide dismutase, glutathione peroxidase-related genes, thioredoxin and thioredoxin reductase, suggesting it is highly tolerant to oxidative conditions. Finally, genes for radiation resistance, biodesulfurization, and oil and phenol degrading pathways were also detected. Altogether this data make R. erythropolis S43 a good candidate microorganism for bioremediation of highly contaminated environments and other industrial applications.

Advanced Rhodococcus Biocatalysts for Environmental Biotechnologies

“…The organic solvent-tolerant Rhodococcus opacus strain B-4 survived for at least 5 days in n-tetradecane, oleyl alcohol, and bis(2-ethylhexyl)phthalate, which contained water less than 1% (w/v) [63]. Minimal inhibitory concentrations of heavy metals (Cd, Cs, Cr, Cu, Mo, Ni, Pb, Zn, and V) for Rhodococcus reached up to 250 mM; moreover, rhodococci were able to detoxify heavy metals and metalloids (As), changing their oxidation level [64,65].…”

“…The organic solvent-tolerant Rhodococcus opacus strain B-4 survived for at least 5 days in n-tetradecane, oleyl alcohol, and bis(2-ethylhexyl)phthalate, which contained water less than 1% (w/v) [63]. Minimal inhibitory concentrations of heavy metals (Cd, Cs, Cr, Cu, Mo, Ni, Pb, Zn, and V) for Rhodococcus reached up to 250 mM; moreover, rhodococci were able to detoxify heavy metals and metalloids (As), changing their oxidation level [64,65].Both Rhodococcus whole cells and purified enzymes are currently used as biocatalysts. Enzymatic catalysts guarantee high reaction selectivity and the absence of side reactions, while whole cells perform multi-step bioconversions and allow easy cofactor regeneration [66].…”

Editorial: Actinobacteria, a Source of Biocatalytic Tools

“…; López-García et al; Šetinová et al). Growth limiting conditions (Fe-, N-, S-limitations or presence of toxic compounds/elements) are often used to overproduce target compounds and among those the secondary metabolites siderophores (Retamal-Morales et al, 2017, 2018b; Senges et al, 2018) and biosurfactants (Kügler et al, 2015; Retamal-Morales et al, 2018a) can be mentioned.…”

Biodegradation of High Concentrations of Aliphatic Hydrocarbons in Soil from a Petroleum Refinery: Implications for Applicability of New Actinobacterial Strains

“…Both actinobacterial strains investigated in this study are proven producers of siderophores, which bind Fe 3+ and other trivalent metals, thereby affecting their bioavailability [26,53,54]. As such, we included iron treatment and DFOB siderophore biostimulation within our test variants of experiment B. Theoretically, the presence of Fe 3+ should suppress siderophore production, allowing microorganisms to have a non-iron limiting metabolism [55]; however, the effects of Fe 2+ , DFOB and siderophores may differ.…”