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Alkaline cyanide biodegradation by Pseudomonas pseudoalcaligenes CECT5344
V M Luque-Almagro1, R Blasco, M J Huertas
1Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Córdoba 14071, Spain.
Biochemical Society Transactions
|January 26, 2005
Summary
Pseudomonas pseudoalcaligenes CECT5344 metabolizes toxic cyanide compounds into ammonium under alkaline conditions. This cyanide-resistant bacterium offers a promising bioremediation solution for industrial wastewater, utilizing alternative oxidase and iron acquisition mechanisms.
Area of Science:
- Microbiology
- Environmental Science
- Biotechnology
Background:
- Cyanide compounds are highly toxic and prevalent in industrial wastewater.
- Alkaline conditions can mitigate hydrogen cyanide (HCN) volatilization but pose challenges for microbial degradation.
- Bioremediation using specialized microorganisms is a sustainable approach for treating cyanide-contaminated sites.
Purpose of the Study:
- To investigate the capability of Pseudomonas pseudoalcaligenes CECT5344 to utilize various cyanoderivatives as nitrogen sources.
- To understand the mechanisms of cyanide resistance and degradation employed by this bacterial strain.
- To evaluate its potential for bioremediation of cyanide-containing industrial wastewater.
Main Methods:
- Culturing Pseudomonas pseudoalcaligenes CECT5344 under alkaline conditions with different cyanoderivatives.
- Quantifying cyanide consumption and ammonium production.
- Assessing bacterial growth in the presence of heavy metal and cyanide-laden wastewater.
- Enzyme activity assays for cyanase and beta-cyanoalanine nitrilase.
- Investigating cyanide-induced resistance mechanisms, including alternative oxidase and siderophore production.
Main Results:
- Pseudomonas pseudoalcaligenes CECT5344 efficiently utilizes cyanide, cyanate, and beta-cyanoalanine as nitrogen sources under alkaline pH.
- The bacterium stoichiometrically converts consumed cyanide into ammonium.
- It demonstrates resistance to cyanide and heavy metals, growing in jewellery industry wastewater.
- Cyanide induction triggers the expression of an alternative oxidase and a siderophore-based iron acquisition system.
- Elevated cyanase and beta-cyanoalanine nitrilase activities were detected in induced cells.
Conclusions:
- Pseudomonas pseudoalcaligenes CECT5344 possesses a robust metabolic pathway for degrading cyanoderivatives under alkaline conditions.
- The strain exhibits significant cyanide resistance, employing specific enzymatic and physiological adaptations.
- Its ability to thrive in contaminated industrial wastewater highlights its potential as a valuable agent for cyanide bioremediation.