Papers by Olusola Solomon Amodu
OnLine Journal of Biological Sciences
Corrosion Inhibitors
The suitability of Musa paradisiaca (banana) peel extract as a green corrosion inhibitor for mild... more The suitability of Musa paradisiaca (banana) peel extract as a green corrosion inhibitor for mild steel in acidic medium (1 M HCl) was investigated using factorial method of the design of experiment. The effects of two independent variables (concentration of banana peel extract and temperature) on the corrosion inhibition efficiency were investigated. The physicochemical properties of the extract such as surface tension, viscosity, flash point, and specific gravity were determined using standardized methods provided by the American System of Testing Materials (D-971). The relationship between the independent variables and the inhibitor efficiency was modeled by gasometric and thermometric methods. The statistical analysis of the inhibition efficiency was carried out using the "Fit Regression Model" of Minitab ® 17.0, while the fitness of the models was assessed by the coefficient of determination (R 2) and the analysis of variance (ANOVA). From the results obtained, gasometric method achieved a maximum inhibition efficiency of 66.83%, with an R 2 of 90.76%, whereas thermometric method gave a maximum inhibition efficiency of 65.70%, with an R 2 of 95.56%. This study shows that banana peel extract has the capacity to prevent the corrosion of mild steel in acidic medium.
Thesis submitted in fulfilment of the requirements for the degree of Doctor Technologiae: Chemica... more Thesis submitted in fulfilment of the requirements for the degree of Doctor Technologiae: Chemical Engineering, Faculty of Engineering at the Cape Peninsula University of Technology - Cape Town, South Africa
African Journal of Biotechnology, 2016
Polycyclic aromatic hydrocarbons (PAHs) are recalcitrant contaminants which are routinely found i... more Polycyclic aromatic hydrocarbons (PAHs) are recalcitrant contaminants which are routinely found in numerous environmental matrices, contributing to ecological degradation. In this study, the removal of LMW and HMW PAHs with 4- and 5 benzene rings, by Bacillus licheniformis STK 01, Bacillus subtilis STK 02 and Pseudomonas aeruginosa STK 03, was evaluated in silty soil for a period of 60 days. Subsequently, a biosurfactant produced from Beta vulgaris agrowaste was used to augment the removal of the aforementioned PAHs in mono- and co cultures. The isolates proved to be proficient in removing the contaminants, with B. licheniformis STK01 cultures achieving the highest removal rates. Biosurfactant supplementation significantly enhanced the removal of benzo(a)pyrene- a 5-ring benzene HMW PAH. The highest removal rates achieved in biosurfactant supplemented cultures were: 100% for phenanthrene, 95.32% for pyrene, 82.71% for benz(a)anthracene and 86.17% for benzo(a)pyrene. The kinetic dat...
Journal of Water Reuse and Desalination, 2018
The adsorption of alizarin red (AR) dye onto termite hill sample (THs) was investigated. Prior to... more The adsorption of alizarin red (AR) dye onto termite hill sample (THs) was investigated. Prior to the adsorption studies, the elemental, morphological, surface and structural properties of THs were examined by modern analytical methods. Instrumental analysis showed that the homogenous micro-structured THs are comprised of iron oxide, silica oxide, and alumina as major components. Experiments showed that the adsorption capacity of AR decreases with increasing pH and initial AR concentrations, and increases with increasing contact time, stirring speed and temperature. The equilibrium study obeyed the Langmuir adsorption model and the kinetics followed the pseudo-second-order model. About 95.0% AR reduction (1.425 mg/g) was achieved when 0.8 g of THs was mixed with 30 mL of 40 mg/L AR solution for 120 min at 400 rpm and a pH of 2. Thermodynamic study suggested that AR adsorption onto THs is spontaneous at higher temperatures of 323 K and above (ΔGo values are negative). However, ΔGo ar...
Carpathian Journal of Earth and Environmental Sciences, 2018
Background: Globally, it is known that HIV-infected pregnant women are prone to depressive sympto... more Background: Globally, it is known that HIV-infected pregnant women are prone to depressive symptoms. Research evidences also suggest that nutrient deficiencies may enhance the depressive illness, and that fish oil omega-3 fatty acids may alleviate the depressive symptoms. The aim of this study was to assess the effect of fish oil omega-3 eicosapentaenoic acid-rich supplements on depressive symptoms among HIV-seropositive pregnant women. Trial design: A randomized double-blinded controlled trial with two parallel groups was conducted. The intervention group received fish oil omega-3 of 3.17 g (eicosapentaenoic acid = 2.15 g; docosahexaenoic acid = 1.02 g) per day for 8 weeks, while the control group received soybean oil for a similar period. Method: Participants were HIV-seropositive pregnant women who were enrolled in prevention of mother-to-child transmission programs and attending antenatal clinics at selected Nairobi city county's health facilities. Recruitment was done from health records of HIV-infected pregnant women. Data analysis followed per-protocol analysis. Participants who completed the 8-week trial were included in the analysis of covariance statistical model with omega-3 as main effect. The covariates in the change in BDI-II depressive symptom score outcome were baseline characteristics and nutrient adequacy. Results: 282 participants were recruited 109 randomized to fish oil, and 107 to soybean oil. Completion rate was 86/109 (78.9%) and 96/107 (89.7%) respectively. At the end of week-8 of follow up most participants in both arms had mild depressive symptoms 82/86 (95.3%) in the Fish oil group and 94/96 (97.9%) in the Soybean oil group. The difference in effect between the intervention and control group was not statistically significant (1.01 (95% CI − 0.58 to 2.60), p = 0.21). Conclusion: Fish oil omega-3 with a daily dosage of 3.17 g (eicosapentaenoic acid = 2.15 g; docosahexaenoic acid = 1.02 g) appears to provide no added benefit in reduction of the symptoms of depression in HIV-infected pregnant women.
The Canadian Journal of Chemical Engineering, 2016
The kinetics of cell growth, substrate utilization, and biosurfactant production by Bacillus lich... more The kinetics of cell growth, substrate utilization, and biosurfactant production by Bacillus licheniformis STK 01 from a solid agrowaste substrate (Beta vulgaris) and a refined substrate (mineral salts, MS) was investigated. Data obtained were fitted to the integrated Monod equation, logistic models, and Leudeking–Piret model using nonlinear regression analyses. The maximum cell growth was observed after 72 h of fermentation for both substrates. The highest biosurfactant production was 5.8 ± 0.5 g/L when the B. vulgaris waste substrate was used, while the production increased up to 9.78 ± 1.02 g/L when MS was used. The biosurfactant produced from B. vulgaris and MS lowered the surface tension of the broth to 30 and 23.5 mN/m respectively. Furthermore, from the kinetic data analyses, cell growth and B. vulgaris utilization were described by the logistic model and modified Monod equation, respectively, with the maximum cell growth rate of 0.026 h−1, cell yield of 0.617, and the Monod saturation constant being 0.418 g/L. Similarly, biosurfactant production was best described by the logistic model while the production rate constant was 0.140 h−1. This study is applicable, among other areas, in the design of biological systems augmented with B. vulgaris waste.
Journal of Encapsulation and Adsorption Sciences, 2015
This work reports the adsorption of crystal violet (CV) dye onto magnetic zeolite (MZ) nanopartic... more This work reports the adsorption of crystal violet (CV) dye onto magnetic zeolite (MZ) nanoparticles, synthesized by direct fusion of fly ash (FA) and magnetite particles. The synthesised MZ showed high capacity for CV dye adsorption, removing 95% of the dye at an equilibrium adsorption time of 10 min and 25˚C. The effects of adsorbent dosage, dye concentration, and pH, on adsorption were evaluated. Adsorption data were best described by the Langmuir adsorption isotherm (R 2 = 0.9986), while the adsorption kinetics was best fitted by the pseudo-second-order kinetic model (R 2 = 0.9999). Application of the MZs synthesised from inexpensive resources such as FA could ensure the sustainability and cost effectiveness of treating industrial effluent containing basic dyes, especially effluent from the textile industries.
3 Biotech, 2015
An alkali-tolerant bacterium, Pseudomonas aeruginosa STK 03 (accession number KR011154), isolated... more An alkali-tolerant bacterium, Pseudomonas aeruginosa STK 03 (accession number KR011154), isolated from an oil spill site, was evaluated for the biodegradation of free cyanide and thiocyanate under alkaline conditions. The organism had a free cyanide degradation efficiency of 80 and 32 % from an initial concentration of 250 and 450 mg CN-/L, respectively. Additionally, the organism was able to degrade thiocyanate, achieving a degradation efficiency of 78 and 98 % from non-and free cyanide spiked cultures, respectively. The organism was capable of heterotrophic nitrification but was unable to denitrify aerobically. The organism was unable to degrade free cyanide in the absence of a carbon source, but it was able to degrade thiocyanate heterotrophically, achieving a degradation efficiency of 79 % from an initial concentration of 250 mg SCN-/L. Further increases in thiocyanate degradation efficiency were only observed when the cultures were spiked with free cyanide (50 mg CN-/L), achieving a degradation efficiency of 98 % from an initial concentration of 250 mg SCN-/L. This is the first study to report free cyanide and thiocyanate degradation by Pseudomonas aeruginosa. The higher free cyanide and thiocyanate tolerance of the isolate STK 03, which surpasses the stipulated tolerance threshold of 200 mg CN-/L for most organisms, could be valuable in microbial consortia for the degradation of cyanides in an industrial setting.
Environmental Biotechnology - New Approaches and Prospective Applications, 2013
BioResources, 2014
Novel biosurfactant-producing strains were isolated from hydrocarboncontaminated environments tha... more Novel biosurfactant-producing strains were isolated from hydrocarboncontaminated environments that exclusively utilize agro-waste as their primary carbon source for the expression of biosurfactants. These were quantified using various standardized methods. Among the agro-waste screened, Beta vulgaris (Beetroot) proved to be the most suitable substrate, for which the biosurfactants produced by three bacterial isolates-B. licheniformis STK01, B. subtilis STK02, and P. aeruginosa STK03-lowered the surface tension of the culture media to 30.0, 32.98, and 30.37 mN/m, respectively. The biosurfactants achieved considerable emulsification activity, particularly for heavy hydrocarbons, with the highest emulsification indices being 65.5% and 95% for anthracene and lubricant oil, respectively. The emulsion formed with lubricant oil was thermally stable even up to 50 °C for 21 days. The results showed the proficiency of the novel bacterial isolates used, as well as the suitability of solid agro-waste for biosurfactant production, thus suggesting that exclusive utilization of solid agro-waste is a promising option for use in biosurfactant production for environmental remediation. The outstanding emulsification activity and thermal stability demonstrated by the biosurfactants produced showed their potential applications in enhancing bioavailability and bioremediation of recalcitrant and hydrophobic environmental contaminants.
BioResources, 2014
This work reports on the exploitation of Beta vulgaris for biosurfactant production by Bacillus l... more This work reports on the exploitation of Beta vulgaris for biosurfactant production by Bacillus licheniformis STK 01 and its optimization using statistical modeling of response surface methodology (RSM). Three variables were investigated: agro-waste concentration, pH, and temperature. The response and contour plots of the RSM showed perfect interaction among the variables, with the highest surface tension reduction of the culture medium to 30 mN/m observed at 42 °C, a pH of 8, and a substrate concentration of 4% (w/v). The biosurfactant produced demonstrated a high tendency for hydrocarbon emulsification. Furthermore, by numerical optimization techniques, the optimum conditions were found to be as follows: a pH of 6.72, an agro-waste concentration of 4% (w/v), and a temperature of 44.5 °C. The experiment conducted to validate the optimum conditions obtained showed a biosurfactant with remarkable surface activity, lowering the surface tension of the broth to 30 mN/m, when the organism was grown on B. vulgaris, and to 23.5 mN/m, when grown in glucose mediumthe later representing one of the highest surface tension reductions ever reported for a biosurfactant. This study revealed, among others, that the exclusive utilization of cheap solid agro-waste without supplementation with a refined nutrient source is feasible and could ensure the economic sustainability of biosurfactant production.
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Papers by Olusola Solomon Amodu