Please use this identifier to cite or link to this item: http://hdl.handle.net/11189/5601
Title: Co-metabolism of thiocyanate and free cyanide by Exiguobacterium acetylicum and Bacillus marisflavi under alkaline conditions
Authors: Mekuto, Lukhanyo 
Alegbeleye, Oluwadara Oluwaseun 
Ntwampe, Seteno KO 
Ngongang, Maxwell Mewa 
Mudumbi, John Baptist 
Akinpelu, Enoch Akinbiyi 
Keywords: B. marisflavi;Biodegradation;E. acetylicum;Free cyanide;Co-metabolism;Thiocyanate
Issue Date: 2016
Publisher: 3 Biotech
Source: Mekuto, L., Alegbeleye, O.O., Ntwampe, S.K.O. et al. 3 Biotech (2016) 6: 173. doi:10.1007/s13205-016-0491-x
Abstract: The continuous discharge of cyanide-containing effluents to the environment has necessitated for the development of environmentally benign treatment processes that would result in complete detoxification of the cyanide-containing wastewaters, without producing additional environmental toxicants. Since biological detoxification of hazardous chemical compounds has been renowned for its robustness and environmental-friendliness, the ability of the Exiguobacterium acetylicum (GenBank accession number KT282229) and Bacillus marisflavi (GenBank accession number KR016603) to co-metabolise thiocyanate (SCN−) and free cyanide (CN−) under alkaline conditions was evaluated. E. acetylicum had an SCN− degradation efficiency of 99.9 % from an initial SCN− concentration of 150 mg SCN−/L, but the organism was unable to degrade CN−. Consequently, B. marisflavi had a CN− degradation efficiency of 99 % from an initial concentration of 200 mg CN−/L. Similarly, the organism was unable to degrade SCN−; hence, this resulted in the evaluation of co-metabolism of SCN− and CN− by the two microbial species. Optimisation of operational conditions was evaluated using response surface methodology (RSM). A numeric optimisation technique was used to evaluate the optimisation of the input variables i.e. pH, temperature, SCN− and CN− concentrations. The optimum conditions were found to be as follows: pH 9.0, temperature 34 °C, 140 mg SCN−/L and 205 mg CN−/L under which complete SCN− and CN− degradation would be achieved over a 168-h period. Using the optimised data, co-metabolism of SCN− and CN− by both E. acetylicum and B. marisflavi was evaluated, achieving a combined degradation efficiency of ≥99.9 %. The high degradative capacity of these organisms has resulted in their supplementation on an active continuous biological degradation system that is treating both SCN− and CN−.
URI: http://dx.doi.org/10.1007/s13205-016-0491-x
http://hdl.handle.net/11189/5601
Appears in Collections:Prof. Seteno Karabo Ntwampe
BioERG - Journal articles (DHET subsidised)
Appsc - Journal Articles (DHET subsidised)

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