Abstract
Aims: To identify bacteria with high selenium tolerance and reduction capacity for bioremediation of wastewater and nanoselenium particle production. Methods and Results: A bacterial endophyte was isolated from the selenium hyperaccumulator Stanleya pinnata (Brassicaceae) growing on seleniferous soils in Colorado, USA. Based on fatty acid methyl ester analysis and multi-locus sequence analysis (MLSA) using 16S rRNA, gyrB, rpoB and rpoD genes, the isolate was identified as a subspecies of Pseudomonas moraviensis (97·3% nucleotide identity) and named P. moraviensis stanleyae. The isolate exhibited extreme tolerance to SeO<inf>3</inf><sup>2-</sup> (up to 120 mmol l<sup>-1</sup>) and SeO<inf>4</inf><sup>2-</sup> (>150 mmol l<sup>-1</sup>). Selenium oxyanion removal from growth medium was measured by microchip capillary electrophoresis (detection limit 95 nmol l<sup>-1</sup> for SeO<inf>3</inf><sup>2-</sup> and 13 nmol l<sup>-1</sup> for SeO<inf>4</inf><sup>2-</sup>). Within 48 h, P. moraviensis stanleyae aerobically reduced SeO<inf>3</inf><sup>2-</sup> to red Se(0) from 10 mmol l<sup>-1</sup> to below the detection limit (removal rate 0·27 mmol h<sup>-1</sup> at 30°C); anaerobic SeO<inf>3</inf><sup>2-</sup> removal was slower. No SeO<inf>4</inf><sup>2-</sup> removal was observed. Pseudomonas moraviensis stanleyae stimulated the growth of crop species Brassica juncea by 70% with no significant effect on Se accumulation. Conclusions: Pseudomonas moraviensis stanleyae can tolerate extreme levels of selenate and selenite and can deplete high levels of selenite under aerobic and anaerobic conditions. Significance and Impact of the Study: Pseudomonas moraviensis subsp. stanleyae may be useful for stimulating plant growth and for the treatment of Se-laden wastewater.
Original language | English |
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Pages (from-to) | 400-410 |
Number of pages | 11 |
Journal | Journal of Applied Microbiology |
Volume | 119 |
Issue number | 2 |
DOIs | |
Publication status | Published - 1 Aug 2015 |
Keywords
- Pseudomonas moraviensis
- Stanleya pinnata
- Aerobic selenite reduction
- Elemental selenium nanoparticles
- Microchip capillary electrophoresis
- Multi-locus sequence analysis