Biodegradation of Free Cyanide by a New Isolated Alkaliphilic Bacillus licheniformis Strain

Microbial treatment of free-cyanide-polluted wastewater is a cost-effective, efficient, and eco-friendly method. Free-cyanide-degrading microbial cultures were isolated from different sources using batch-enrichment culture techniques, with acetate as the carbon source. Five microbial cultures were a...

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Bibliographic Details
Published in:Microbiology research 2024-03, Vol.15 (1), p.33-49
Main Authors: Uribe-Ramírez, Daniel, Cristiani-Urbina, Eliseo, Morales-Barrera, Liliana
Format: Article
Language:English
Subjects:
Acetic acid
alkaliphilic bacterial strain
Ammonia
Aqueous solutions
Bacillus licheniformis
Bacteria
Biodegradation
Carbon
Carbon sources
Cell growth
Culture techniques
cyanide
Cyanides
Cytochrome
Detoxification
Efficiency
enrichment cultures
Enrichment media
Metabolism
Microorganisms
Morphology
Nitrogen
wastewater
Wastewater pollution
Wastewater treatment
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Summary:Microbial treatment of free-cyanide-polluted wastewater is a cost-effective, efficient, and eco-friendly method. Free-cyanide-degrading microbial cultures were isolated from different sources using batch-enrichment culture techniques, with acetate as the carbon source. Five microbial cultures were able to tolerate and grow at 1500 mg/L free cyanide, which was used as the only nitrogen source under strongly alkaline conditions (pH = 11). Among them, one bacterial strain (B11) was selected for further study because of its high free-cyanide-biodegradation efficiency. Bacterial strain B11 was molecularly identified as Bacillus licheniformis CDBB B11. Free cyanide inhibited the growth rate of B. licheniformis CDBB B11 at initial cyanide concentrations >75 mg/L. Despite this, the bacterial strain demonstrated 100% cyanide-biodegradation efficiency at initial cyanide concentrations ranging from 25 to 75 mg/L, which decreased to 32% as the initial cyanide concentration increased from 75 to 1500 mg/L. Free-cyanide biodegradation corresponds to bacterial growth and ammonia accumulation in the culture medium. The alkaliphilic B. licheniformis CDBB B11 strain is a robust candidate for the detoxification of free-cyanide-laden wastewater because it tolerates and efficiently degrades free cyanide at concentrations of up to 1500 mg/L.
ISSN:2036-7481
2036-7481
DOI:10.3390/microbiolres15010003