Pseudomonas moraviensis subsp. stanleyae, a bacterial endophyte of hyperaccumulator Stanleya pinnata, is capable of efficient selenite reduction to elemental selenium under aerobic conditions

J Appl Microbiol. 2015 Aug;119(2):400-10. doi: 10.1111/jam.12842. Epub 2015 Jun 24.


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 SeO3(2-) (up to 120 mmol l(-1)) and SeO4(2-) (>150 mmol l(-1)). Selenium oxyanion removal from growth medium was measured by microchip capillary electrophoresis (detection limit 95 nmol l(-1) for SeO3(2-) and 13 nmol l(-1) for SeO4(2-)). Within 48 h, P. moraviensis stanleyae aerobically reduced SeO3(2-) to red Se(0) from 10 mmol l(-1) to below the detection limit (removal rate 0.27 mmol h(-1) at 30 °C); anaerobic SeO3(2-) removal was slower. No SeO4(2-) 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.

Keywords: Pseudomonas moraviensis; Stanleya pinnata; aerobic selenite reduction; elemental selenium nanoparticles; microchip capillary electrophoresis; multi-locus sequence analysis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aerobiosis
  • Biodegradation, Environmental
  • Brassicaceae / metabolism
  • Brassicaceae / microbiology*
  • Endophytes / classification
  • Endophytes / genetics
  • Endophytes / isolation & purification
  • Endophytes / metabolism*
  • Pseudomonas / classification
  • Pseudomonas / genetics
  • Pseudomonas / isolation & purification
  • Pseudomonas / metabolism*
  • Selenious Acid / metabolism*
  • Selenium / metabolism*


  • Selenious Acid
  • Selenium