M.Sc. (Biochemistry) / An Acinetobacter sp. was isolated which had the ability to metabolise both organic nitriles and inorganic cyanide salts. The enzyme responsible for the degradation of the nitrile groups, was found to be an extra-cellular complex. This complex was partially purified and was shown to consist of not only a number of protein fractions, but also a definite lipid fraction which was identified as being fatty acids. The entire complex had a molecular weight of about 80 000 Da. The enzyme complex exhibited a high degree of stability in the crude form, but rapidly lost its activity on further purification. The complex had a Km of 0.154 ug/ml and a Vmax of 0.534 ug/ml/min for KCN as substrate. This Km value indicates that the complex has a high affinity for KCN and may be of use in the removal of cyanide at low levels. The temperature optimum was shown to be 20·C and the pH-optimum 6.5. Fatty acids were produced both in the presence and absence of a nitrile substrate, and it is unclear whether carbon from CN degradation can be channeled into fatty acid synthesis by this particular bacterium. This bacterium was found to be very effective in the degradation of nitrile compounds. The removal of cyanide from mine effluents is of particular interest in South Africa today and no effective biological method is currently in use.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uj/uj:3948 |
| Date | 13 February 2014 |
| Creators | Toerien, Stefan |
| Source Sets | South African National ETD Portal |
| Detected Language | English |
| Type | Thesis |
| Rights | University of Johannesburg |
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