http://hdl.handle.net/11189/3438 2026-08-13T12:21:58Z 2026-08-13T12:21:58Z Mekuto, Lukhanyo Ntwampe, Seteno Karabo Obed Jackson, Vanessa Angela http://hdl.handle.net/11189/1970 2020-08-12T12:12:33Z 2013-01-01T00:00:00Z

Title: Biodegradation of free cyanide using bacterial species isolated from cyanide wastewater Authors: Mekuto, Lukhanyo; Ntwampe, Seteno Karabo Obed; Jackson, Vanessa Angela Abstract: Biodegradation of free cyanide from industrial wastewaters has been proven as a viable and robust method for treatment of wastewaters containing cyanide. Bacterial species degrade cyanide into less toxic products as they are able to use the cyanide as a nitrogen source, forming ammonia and carbon dioxide as end products. Several bacterial species (n = 13) that were isolated from electroplating wastewater were assessed for their ability to degrade cyanide. A co-culture was created by mixing the bacterial strains subsequent to growth on nutrient broth for 48 hours at 37°C, to generate a broth to which free cyanide (200 to 500 ppm) was added to evaluate the species capability to biodegrade the cyanide. The second experimental run was performed using free cyanide (200 and 400 ppm) in batch cultures supplemented solely with agro-waste: [pineapple extract (1% v/v) and beetroot extract (1% v/v)], brewer’s yeast waste extract (1% v/v) and whey (0.5% w/v), as the primary carbon source. The microorganisms were able to degrade 131, 152, 177, 155 mg CN-/L from 200, 300, 400 and 500 mg CN- /L, respectively. It was also noted that the bacterial species were able to degrade free cyanide in a medium that was supplemented solely with agro-waste. In a medium in which whey was used, it was observed that 179 and 239 mg CN-/L was biodegraded from 200 and 400 mg CN-/L cultures, respectively. The primary observations were that, the cyanide degradation efficiency was accompanied by microbial growth; however, the depletion of reducing sugars in the broth affected the degradation efficiency for all cultures. Description: Biodegradation of free cyanide using bacterial species isolated from cyanide wastewater, 4th World Congress on Biotechnology

2013-01-01T00:00:00Z Amodu, Olusola Solomon Ntwampe, Seteno Karabo Obed Ojumu, Tunde Victor http://hdl.handle.net/11189/1901 2020-08-12T12:01:48Z 2013-01-01T00:00:00Z

Title: Isolation of biosurfactant producing strains for enhanced bioavailability of hydrocarbon contaminants Authors: Amodu, Olusola Solomon; Ntwampe, Seteno Karabo Obed; Ojumu, Tunde Victor Abstract: Biosurfactants are surface active agents produced by microorganisms. Due to their amphiphilic structure, biosurfactants show a wide range of properties, including the lowering of surface and interfacial tension of liquids, the ability to form micelles and microemulsions between two different phases, the ability to increase the surface area of hydrophobic water-insoluble substances, and thus increase the water bioavailability of such substances. The present study focused on the isolation of novel biosurfactant producing strains from hard surfaces (tar surfaces) which exclusively utilize agrowaste as their primary carbon source for the expression of the biosurfactants – quantified using various standardized methods. Agrowastes used were; Pear (P, Pyrus), Pineapple (PP, Ananas comosus), Apple (A, Malus domestica), Beetroot (B, Beta vulgaris), Brewers spent yeast (SPY), PP plus SPY, B plus SPY, P plus SPY, PP plus SPY and A plus SPY. The drop-collapse method showed that the highest biosurfactant production was achieved using B. vulgaris. Surface tension reduction and emulsification index were used to screen the biosurfactant produced for its potential application in enhancing bioavailability of hydrocarbon contaminants. Emulsification was carried out using diesel, engine oil, cyclohexane, phenanthrene and benz(a)anthracene as hydrocarbons. The biosurfactant produced using B. vulgaris waste as a sole carbon source (without supplementation with refined carbohydrates, inducers, etc.) was able to lower the surface tension of the medium to 33 mN/m within 4 days of incubation without optimization – for which the crude extract formed stable emulsions. The results obtained in this study demonstrated the feasibility of producing biosurfactants using renewable and easily available resources as sole and primary carbon sources. The emulsification achieved showed the biosurfactants’ propensity for use in enhancing bioavailability and hence, bioremediation of an environment contaminated with various hydrocarbons. Description: 4th World Congress on Biotechnology September 23-25, 2013 DoubleTree by Hilton Hotel Raleigh-Durham Airport at RTP, NC, USA

2013-01-01T00:00:00Z