Oxidation of arsenite by two β-proteobacteria isolated from soil

Abstract

Two heterotrophic As(III)-oxidizing bacteria, SPB-24 and SPB-31 were isolated from garden soil. Based on 16S rRNA gene sequence analysis, strain SPB-24 was closely related to genus Bordetella, and strain SPB-31 was most closely related to genus Achromobacter. Both strains exhibited high As(III) (15 mM for SPB-24 and 40 mM for SPB-31) and As(V) (>300 mM for both strains) resistance. Both strains oxidized 5 mM As(III) in minimal medium with oxidation rate of 554 and 558 μM h(-1) for SPB-24 and SPB-31, respectively. Washed cells of both strains oxidized As(III) over broad pH and temperature range with optimum pH 6 and temperature 42°C for both strains. The As(III) oxidation kinetic by washed cells showed K (m) and V (max) values of 41.7 μM and 1,166 μM h(-1) for SPB-24, 52 μM and 1,186 μM h(-1) for SPB-31. In the presence of minimal amount of carbon source, the strains showed high As(III) oxidation rate and high specific arsenite oxidase activity. The ability of strains to resist high concentration of arsenic and oxidize As(III) with highest rates reported so far makes them potential candidates for bioremediation of arsenic-contaminated environment.

Arsenite-oxidizing bacteria exhibiting plant growth promoting traits isolated from the rhizosphere of Oryza sativa L.: Implications for mitigation of arsenic contamination in paddies

“…SPB-24 (12.6 nM min −1 mg −1 protein) and Achromobacter sp. SPB-31 (12.2 nM min −1 mg −1 protein) [35] and Arthrobacter sp. (10.0 nM min −1 mg −1 protein) [36].…”

Biodegradation of Reactive Black 5 by Aeromonas hydrophila strain isolated from dye-contaminated textile wastewater

“…The polymerase chain reaction (PCR) amplification and DNA sequencing of the 16s rRNA gene was carried out as described earlier [14]. Almost the full length of 16S rRNA gene was amplified by PCR using universal primers forward 5′-AGAGTTTGATMTGGCTCAG-3′ and 5′-CGGYTACCTTGTTACGACTT-3′ corresponding to the positions 9 to 27 and 1525 to 1545, respectively, in the 16S rRNA gene sequence.…”

Rhizosphere-induced heavy metal(loid) transformation in relation to bioavailability and remediation

“…Redox reactions influence the speciation and mobility of metal(loid)s. For example, metals generally are less soluble in their higher oxidation state, whereas the solubility and mobility of metalloids depend on both the oxidation state and the ionic form (Ross, 1994). In the case of sediments and soils, As(III) can be oxidized to As(V) by bacteria (Bachate et al, 2012;Battaglia-Brunet et al, 2002). The strong affinity of As(V) towards inorganic soil components, results in the immobilization of As after the oxidation process.…”