- Title
- Oxidation of arsenite to arsenate in growth medium and groundwater using a novel arsenite-oxidizing diazotrophic bacterium isolated from soil
- Creator
- Bahar, Md Mezbaul; Megharaj, Mallavarapu; Naidu, Ravi
- Relation
- International Biodeterioration and Biodegradation Vol. 106, Issue January 2016, p. 178-182
- Publisher Link
- http://dx.doi.org/10.1016/j.ibiod.2015.10.019
- Publisher
- Elsevier
- Resource Type
- journal article
- Date
- 2016
- Description
- An arsenic hyper-tolerant diazotrophic bacterium was isolated from a heavy metal contaminated soil. The pure isolate MM-17 was identified as Azospirillum sp. based on phylogenetic analysis of 16S rRNA. The strain oxidized 100 µM As(III) to As(V) in both culture media (minimal salts) and real groundwater within 8 and 10 h, respectively. The oxidation of As(III) by this strain was observed within the pH range 5-10 with the best performance at pH 7-8. As(III) oxidation was found to be independent of cell growth which implies the oxidation enzymes are constitutively expressed. The whole cell kinetic study highlighted a lower value of kinetic constant, Ks as 32.9 µM As(III), which indicates that the strain MM-17 has greater affinity for As(III). The gene sequence of the large subunit of arsenite oxidase of MM-17 showed 99 and 72% similarity to the large subunit of arsenite oxidase of Stenotrophomonas sp. MM-7 and Sinorhizobium sp. M14, respectively. Sphaeroplasts experiments suggest that arsenite oxidase is a membrane associated protein in MM-17.
- Subject
- As(III) oxidation; N₂-fixing bacteria; <i>Azospirillum</i> sp.; arsenic detoxification; arsenite oxidase
- Identifier
- http://hdl.handle.net/1959.13/1320110
- Identifier
- uon:24068
- Identifier
- ISSN:0964-8305
- Language
- eng
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