Selenium Biotransformations in an Engineered Aquatic Ecosystem for Bioremediation of Agricultural Wastewater via Brine Shrimp Production

Schmidt, Radomir; Tantoyotai, Prapakorn; Fakra, Sirine C.; Marcus, Matthew A.; Yang, Soo In; Pickering, Ingrid J.; Bañuelos, Gary S.; Freeman, John L.

doi:10.1021/es305001n

Cited by 14 publications

(13 citation statements)

References 54 publications

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“…Some of the biotransformed selenium species were incorporated and bioaccumulated as organic selenium compounds, as they were transferred between the different trophic levels. Organic selenium-enriched invertebrates suitable for human and animal consumption were produced as a result of these metabolic biotransformations (109).…”

Section: Selenium Bioremediationmentioning

confidence: 99%

Microbial Transformations of Selenium Species of Relevance to Bioremediation

Eswayah

Smith

Gardiner

2016

Appl Environ Microbiol

173

102

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b Selenium species, particularly the oxyanions selenite (SeO 3 2؊ ) and selenate (SeO 4 2؊ ), are significant pollutants in the environment that leach from rocks and are released by anthropogenic activities. Selenium is also an essential micronutrient for organisms across the tree of life, including microorganisms and human beings, particularly because of its presence in the 21st genetically encoded amino acid, selenocysteine. Environmental microorganisms are known to be capable of a range of transformations of selenium species, including reduction, methylation, oxidation, and demethylation. Assimilatory reduction of selenium species is necessary for the synthesis of selenoproteins. Dissimilatory reduction of selenate is known to support the anaerobic respiration of a number of microorganisms, and the dissimilatory reduction of soluble selenate and selenite to nanoparticulate elemental selenium greatly reduces the toxicity and bioavailability of selenium and has a major role in bioremediation and potentially in the production of selenium nanospheres for technological applications. Also, microbial methylation after reduction of Se oxyanions is another potentially effective detoxification process if limitations with low reaction rates and capture of the volatile methylated selenium species can be overcome. This review discusses microbial transformations of different forms of Se in an environmental context, with special emphasis on bioremediation of Se pollution. Since the discovery in 1954 by Pinsent that the oxidation of formate by cell suspensions of Escherichia coli requires growth medium containing molybdate and selenite, there has been a growing interest in the biochemical role of selenium in microorganisms (1). Se is an essential component of selenoamino acids, such as selenomethionine and selenocysteine (the 21st proteinogenic amino acid), that occur in certain types of prokaryotic enzymes. Indeed, the requirement for selenite in E. coli growing on formate is linked to the fact that formate dehydrogenase contains selenocysteine. Other prokaryotic enzymes that contain selenocysteine include glycine reductase in several clostridia, formate dehydrogenases in diverse prokaryotes, including Salmonella, Clostridium, and Methanococcus, as well as hydrogenases in Methanococcus and other anaerobes. In addition, other bacterial Se-dependent enzymes, in which the selenium is part of the active site molybdenum-containing cofactor, include nicotinic acid dehydrogenase and xanthine dehydrogenase, which is present in certain clostridial species (2-4).Reactions that are involved in the cycling of Se in soil, including those influenced by microbes, are diagrammatically summarized in Fig. 1 2Ϫ and was spatially separated from sulfate reduction in the environment despite the presence of substantial concentrations of sulfate where it occurred. Thus, it can be concluded that Se and S have different reductive biogeochemical cycles and appear to involve distinct populations of microorganisms.With respect to the remediation of sel...

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Section: Selenium Bioremediationmentioning

confidence: 99%

Microbial Transformations of Selenium Species of Relevance to Bioremediation

Eswayah

Smith

Gardiner

2016

Appl Environ Microbiol

173

102

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“…Active and passive reduction processes to mitigate aquatic Se include direct chemical treatment 2 , reverse osmosis 2 , and biological treatment options, such as artificial wetlands 8 , 9 and bioreactors 7 . Bioreactors are a common tool for biological treatment of wastewater 10 , and this method has been successfully used to reduce the concentration of Se in coalmine effluent on a pilot-scale 7 , 11 .…”

Section: Introductionmentioning

confidence: 99%

N-P Fertilization Stimulates Anaerobic Selenium Reduction in an End-Pit Lake

Luek

Rowan

Rasmussen

2017

Sci Rep

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Selenium (Se), an essential micro nutrient, is toxic to aquatic life at slightly higher water concentrations. Watersheds receiving leachate from selenium rich sources require large-scale, long-term treatment to mitigate Se toxicity. We applied the principles of anaerobic bacterial bioreactors, previously successful in small scale Se mitigation, to a whole end-pit lake ecosystem. Fertilization of the lake with N and P increased primary production, creating a meromictic, anoxic layer, and enhanced the habitat for locally present, anaerobic, Se and sulfur reducing bacteria. Within two years, Se concentrations were reduced ten-fold, reaching water-quality guideline values. The successful experiment demonstrated a novel treatment of large volumes of Se-contaminated water, and introduced an inexpensive method to mitigate a persistent aquatic pollutant of global concern.

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“…Several bacteria, such as Enterobacter cloacea, Desulfomicrobium norvegicum, Pseudomonas spp., Rhodospirillum rubrum, Shewanella oneidensis, Thauera selenatis and Bacillus spp., isolated from environments both with and without Se contamination, have been shown to be able to reduce Se metabolically [25,[28][29][30][31][32][33]. Selenium tolerant bacteria have the ability to reduce selenium species in part due to their similarity to sulfur based compounds [34]. In regions where selenium contamination is prevalent, the biological reduction of selenate and/or selenite to Se 0 has been proposed as a remediation mechanism [15,34].…”

Section: Introductionmentioning

confidence: 99%

“…Selenium tolerant bacteria have the ability to reduce selenium species in part due to their similarity to sulfur based compounds [34]. In regions where selenium contamination is prevalent, the biological reduction of selenate and/or selenite to Se 0 has been proposed as a remediation mechanism [15,34]. To better understand potential Se sources and sinks in anaerobic environments, the limitations of Se bioremediation in reducing environments must be considered.…”

Section: Introductionmentioning

confidence: 99%

Investigating the Effects of Se Solid Phase Substitution in Jarosite Minerals Influenced by Bacterial Reductive Dissolution

2014

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Jarosite minerals (AB 3 (TO 4 ) 2 (OH) 6 ) are iron hydroxysulfate minerals that can readily incorporate trace metals into their mineral structure. A range of metals can be incorporated into the jarosite structure, including oxyanions such as selenate (SeO 4 2− ). Selenium is a micronutrient, but is toxic in relatively low doses. Selenium is present in aqueous systems in its two oxyanion forms: selenate and selenite (SeO 3 2− ). The tetrahedral sulfate coordination site can be completely substituted for selenate in jarosite minerals (NaFe 3 (SO 4 ) x (SeO 4 ) 2-x (OH) 6 ). Bacteria have been observed to reduce Se oxyanions to both more reduced forms and insoluble elemental Se. This is a pathway for selenium immobilization at contaminated sites. This experiment investigates the reductive dissolution of two Se-jarosites (solid substitution containing high and low selenium concentrations) in the presence of Shewanella putrefaciens CN32. It was observed that both Fe(III) and selenate were metabolically reduced and released into solution through jarosite dissolution . Selenate was also found to be incorporated intracellularly and reduced to particulate Se which was released upon cell lysis. Compared to the abiotic samples, enhanced dissolution was found with both the live and dead bacteria treatments.

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Selenium Biotransformations in an Engineered Aquatic Ecosystem for Bioremediation of Agricultural Wastewater via Brine Shrimp Production

Abstract: NOT THE PUBLISHED VERSION; this is the author's final, peer-reviewed manuscript. The published version may be accessed by following the link in the citation at the bottom of the page.

Cited by 14 publications

References 54 publications

Microbial Transformations of Selenium Species of Relevance to Bioremediation

Microbial Transformations of Selenium Species of Relevance to Bioremediation

N-P Fertilization Stimulates Anaerobic Selenium Reduction in an End-Pit Lake

Investigating the Effects of Se Solid Phase Substitution in Jarosite Minerals Influenced by Bacterial Reductive Dissolution

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