Isolation and Characterization of Alkalophilic Cyanide- Degrading Bacteria from Ethiopian Alkalophilic Soda Lakes (Lake Chitu)
| dc.contributor.advisor | Gessesse, Amare (PhD) | |
| dc.contributor.author | Lako, Wajana | |
| dc.date.accessioned | 2019-12-13T08:21:20Z | |
| dc.date.accessioned | 2023-11-09T16:18:30Z | |
| dc.date.available | 2019-12-13T08:21:20Z | |
| dc.date.available | 2023-11-09T16:18:30Z | |
| dc.date.issued | 2007-07-03 | |
| dc.description.abstract | Currently, alkalophillic microbial cyanide degradation has gained greatest attention due to its vital advantages over the acidophilic and /or neutral and conventional cyanide removal methods from industrial wastes. The objectives of this study were to determine how readily alkalophillic cyanotrophic microorganisms could be isolated and screened from enrichment cultures supplied with cyanide as sole source of nitrogen. A total of 63 potential microorganisms were isolated from Lake Chitu mud sediments. Two relatively more active isolates (designated as AUCN-54 & AUCN-60) in resisting and utilizing cyanide were selected for morphological and physiological characterizations. Biomass (dry weight) and protein measurements were the bases for selection. The optimum cyanide concentrations (for maximum growth yield- dry weight and protein) were found to be 10.2mM and 17.34mM for AUCN-54 and AUCN-60, respectively. Thus, AUCN-60 was found to be better in utilizing and resisting cyanide. Both isolates were capable of managing to grow and utilize sodium cyanide a t a salt concentration of 0.25-10 % ( w/v), which was consistent with the salinity of the sample site (microbial original habitat). Concerning the pH, temperature and antibiotics resistance study, clear variations were observed between the two isolates. Interestingly, both of the bacterial isolates were good in utilizing sugarcane molasses as carbon source during cyanide degradation, indicating the need for further study in large scale applications. In addition, both of the cyanotrophic isolates were capable of utilizing potassium thiocyanate as a sole source of nitrogen. On contrary, they were poor in utilizing K2CU(CN)4 as a sole source of nitrogen. This may be attributed to the stability of the cyanide complex due to strong attraction of CNgroup to the central atom in the ligand.The bacterial isolates screened and characterized in this particular study and in their original habitat (sample site) could be of great importance due to their good cyanide utilization capacity and high salt and pH tolerance, which are commonly encountered influential factors in cyanide contaminated waste treatments. | en_US |
| dc.identifier.uri | http://etd.aau.edu.et/handle/12345678/20356 | |
| dc.language.iso | en | en_US |
| dc.publisher | Addis Ababa University | en_US |
| dc.subject | Alkalophiles | en_US |
| dc.subject | Cyanide | en_US |
| dc.subject | Cyanotrophic | en_US |
| dc.subject | Cyanide-Degrading Bacteria | en_US |
| dc.title | Isolation and Characterization of Alkalophilic Cyanide- Degrading Bacteria from Ethiopian Alkalophilic Soda Lakes (Lake Chitu) | en_US |
| dc.type | Thesis | en_US |