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Free cyanide and thiocyanate biodegradation by Pseudomonas aeruginosa STK 03 capable of heterotrophic nitrification under alkaline conditions

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ABSTRACT

An alkali-tolerant bacterium, Pseudomonas aeruginosa STK 03 (accession number KR011154), isolated from an oil spill site, was evaluated for the biodegradation of free cyanide and thiocyanate under alkaline conditions. The organism had a free cyanide degradation efficiency of 80 and 32 % from an initial concentration of 250 and 450 mg CN−/L, respectively. Additionally, the organism was able to degrade thiocyanate, achieving a degradation efficiency of 78 and 98 % from non- and free cyanide spiked cultures, respectively. The organism was capable of heterotrophic nitrification but was unable to denitrify aerobically. The organism was unable to degrade free cyanide in the absence of a carbon source, but it was able to degrade thiocyanate heterotrophically, achieving a degradation efficiency of 79 % from an initial concentration of 250 mg SCN−/L. Further increases in thiocyanate degradation efficiency were only observed when the cultures were spiked with free cyanide (50 mg CN−/L), achieving a degradation efficiency of 98 % from an initial concentration of 250 mg SCN−/L. This is the first study to report free cyanide and thiocyanate degradation by Pseudomonas aeruginosa. The higher free cyanide and thiocyanate tolerance of the isolate STK 03, which surpasses the stipulated tolerance threshold of 200 mg CN−/L for most organisms, could be valuable in microbial consortia for the degradation of cyanides in an industrial setting.

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Autotrophic degradation of free cyanide and ammonium nitrogen formation profile. Error bars represent deviations
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Fig4: Autotrophic degradation of free cyanide and ammonium nitrogen formation profile. Error bars represent deviations

Mentions: Pseudomonas aeruginosa STK 03 was unable to degrade cyanide without the presence of a carbon source, i.e. whey waste (Fig. 4). In the presence of a carbon source, there was a logarithmic increase of ammonium nitrogen from 0 to 40 h and, thereafter, the ammonium concentration reached a plateau. The detection of ammonium nitrogen in the media was due to cell death or disruption and subsequent release of ammonium-related compounds due to cyanide toxicity. This meant that STK 03 was unable to use cyanide as a carbon and nitrogen source and, therefore, an external carbon source was necessary to meet the carbon source requirements of the organism.Fig. 4


Free cyanide and thiocyanate biodegradation by Pseudomonas aeruginosa STK 03 capable of heterotrophic nitrification under alkaline conditions
Autotrophic degradation of free cyanide and ammonium nitrogen formation profile. Error bars represent deviations
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4697911&req=5

Fig4: Autotrophic degradation of free cyanide and ammonium nitrogen formation profile. Error bars represent deviations
Mentions: Pseudomonas aeruginosa STK 03 was unable to degrade cyanide without the presence of a carbon source, i.e. whey waste (Fig. 4). In the presence of a carbon source, there was a logarithmic increase of ammonium nitrogen from 0 to 40 h and, thereafter, the ammonium concentration reached a plateau. The detection of ammonium nitrogen in the media was due to cell death or disruption and subsequent release of ammonium-related compounds due to cyanide toxicity. This meant that STK 03 was unable to use cyanide as a carbon and nitrogen source and, therefore, an external carbon source was necessary to meet the carbon source requirements of the organism.Fig. 4

View Article: PubMed Central - PubMed

ABSTRACT

An alkali-tolerant bacterium, Pseudomonas aeruginosa STK 03 (accession number KR011154), isolated from an oil spill site, was evaluated for the biodegradation of free cyanide and thiocyanate under alkaline conditions. The organism had a free cyanide degradation efficiency of 80 and 32 % from an initial concentration of 250 and 450 mg CN−/L, respectively. Additionally, the organism was able to degrade thiocyanate, achieving a degradation efficiency of 78 and 98 % from non- and free cyanide spiked cultures, respectively. The organism was capable of heterotrophic nitrification but was unable to denitrify aerobically. The organism was unable to degrade free cyanide in the absence of a carbon source, but it was able to degrade thiocyanate heterotrophically, achieving a degradation efficiency of 79 % from an initial concentration of 250 mg SCN−/L. Further increases in thiocyanate degradation efficiency were only observed when the cultures were spiked with free cyanide (50 mg CN−/L), achieving a degradation efficiency of 98 % from an initial concentration of 250 mg SCN−/L. This is the first study to report free cyanide and thiocyanate degradation by Pseudomonas aeruginosa. The higher free cyanide and thiocyanate tolerance of the isolate STK 03, which surpasses the stipulated tolerance threshold of 200 mg CN−/L for most organisms, could be valuable in microbial consortia for the degradation of cyanides in an industrial setting.

No MeSH data available.