Master of Science (M.Sc.) Theses and Dissertations
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- ItemOpen AccessAssessment of the characteristics and potentials of the selected agro-wastes in biogas production in Nigeria.(Institute of Ecology and Environmental studies, Faculty of Science., 2022) OGUNMODEDE, Oluwatosin Ezra.This study determined the rate of biogas production from poultry dropping, swine dung, cassava and banana peels singly and in combination. It also determined the chemical properties of the selected agro-wastes and their conversion to biogas energy. The study further evaluated the quality of biogas produced from those sources. These were with a view to providing information on the potential of those agro-wastes in biogas production in Nigeria. The study was carried out using randomized complete block design. The wastes were taken to the laboratory to determine the chemical properties before mixing into the digesters. Cow dung inoculum was used to introduce biocatalysts called methanogens into the entire treatment, singly and in combination to hasten initial biogas production. The mass of all the wastes treatment singly and in combination was measured using a weighing balance and mixed thoroughly with water until all the lumps were broken, the product (i.e. slurry) was poured into the digesters with the aid of a funnel through the inlet, keeping the outlet and the gas collection pipe closed. The digesters were filled to 75% capacity and the remaining space was left for gas collection. Six treatment groups were used in this study namely; Swine Dung (SD), Poultry Dropping (PD), Cassava Peel (CP),Banana Peel = (BP), Swine Dung + Cassava Peel (SD+CP) and Poultry Dropping + Banana Peel (PD+BP) and each was replicated thrice for a period 30 days retention time. The gas yield was measured using water displacement method, and temperature was recorded daily while pH was recorded on weekly basis. Quality of the biogas produced in term of methane composition was determined by absorption of CO2 component with NaOH in air-tight serum bottle. Data collected was subjected to one-way analysis of variance. The chemical properties of substrates produced before and after biogas production showed that significant difference (p <0.05) existed between the pH values of the six substrates, indicating that variation in pH was largely due to differences in substrate composition. Cassava wastes had the highest total solid content (95.07%) and banana wastes had the least (16.21%). Similarly, cassava wastes had the highest volatile solids content (8.16%) while banana wastes had the least (2.37%) before biogas production. In contrast, cassava had the least moisture content (4.90%) while banana had the highest (83.40%) before and after biogas production. The results also showed that for most set-ups, the biogas production was optimal within the first ten days while it continued to decrease afterwards. Upon comparison, the co-digestion of cassava and swine had the highest biogas production in term of quantity as a result of the amount of water displaced (8.33 L/kg/VS) on the2nd day of set-up. The swine substrate gave the highest biomethane of 57.21% while cassava substrate had the least, 31.10 % value. The study concluded that swine substrate had the highest quality in term of methane composition and the co-digestion of SD+CP gave highest quantity of biogas.
- ItemOpen AccessAssessment of levels of radioactivity and potentially toxic elements in locally pulverized plantain(musa paradislaca L) obtained from osun east senatorial district, Nigeria(The Institute Of Ecology And Environmental Studies, Faculty Of Science, Obafemi Awolowo University, 2022) ABE Toluwalase PatienceThis study assessed the concentrations of potentially toxic elements in the locally produced plantain flour. It also determined the radioactivity levels in the locally produced flour and assessed the human health risk associated with the contaminants. These were with a view to providing information on the concentrations and health risks of the potentially toxic elements and radionuclides in locally produced plantain flour in the study area. Potentially toxic elements were identified by using Proton/Particle Induced X-ray Emission Spectrometry. Correlation, principal component and cluster analyses suggested probable natural and anthropogenic sources of the elements in the pulverized plantain. The Human Health-Risk Assessment of toxic elements was assessed on the basis of geo-Estimated Daily Intake (EDI), Hazard Index (HI), Hazard Quotient (HQ), Carcinogenic Health Effect (Cr) and Ingestion Cancer Slope Factors. Gamma Ray Spectrometer was used to profile 238U, 232Th, and 40K levels in the samples. Activity Concentrations, Radium equivalent activity concentration index (Raeq), Absorbed Gamma Dose Rate (ADR), External Hazard Index (Hex), Internal Hazard Index (Hin), Excess Lifetime Cancer Risk (ELCR) and Annual Effective Dose Equivalent (AEDE) were subsequently evaluated. Twenty-seven elements were detected in the pulverized plantain samples and their concentrations determined. The concentration of elements analyzed in the pulverized plantain samples is in the order K > Cl > Mg > P > Sr > Ca > S > Si > Cd > Rb > Mo > Fe > Al > Ba > Br > Ti > Pb > Bi > Mn > Na > Ni > Cu > Cr > Sc > Zn > As > Co. The analysis of HI revealed extremely health risk. HQ values are lower than the Recommended value > 1 except Cu, Co, Ba, Cd, Pb and As which are comparatively higher. In the test pulverized plantain sample, the meanactivity concentrations of 40K, 232Th and 238U are 117.73 ± 2.52 Bq/kg, 1.66 ± 1.85 Bq/kg and 17.85 ± 17.61 Bq/kg respectively. For the control pulverized plantain samples, the mean activity concentrations of 40K, 232Th and 238U are 11.05±0.43 Bq/kg, 0.37±0.01 Bq/kg and 3.89±0.25 Bq/kg respectively. Although the ELCR calculated shows higher values compared to acceptable value of 2.9 x 10-3 stipulated by UNSCEAR the values of ADR, Raeq, Hex and Hin were significantly lower than or matched well with the permissible values indicating consumption safety for those who do not rely heavily on the consumption of pulverized plantain. The study concluded that the samples from the open markets of the study areas were contaminated with toxic elements, and could at long last pose major health problems to the consumers. However, the results obtained from the radioactivity level of the plantain were below their standard permissible limits. These assessments confirmed that the test pulverized plantain samples exhibited low gamma radiation.
- ItemOpen AccessAnalytical solution of heat transfer problems with generalised Arrhenius reaction rate in three symmetric geometries(Department of Mathematics, Faculty of Science, Obafemi Awolowo University., 2023) ADEBOWALE, Folashade BolanleThis study formulated the one-dimensional thermal balance equation for a a chemical substance at rest in three geometries under constant surface temperature and newtonian cooling obtained analytical solution of the formulated thermal balance equation under realistic condition and examined the effects of constant surface temperature . the exponent of the pre exponential factor and biot number on criticality and transition .these were with a view to generalizing existing works in the literature on thermal explosion, criticality and transition
- ItemEmbargoPurification and characterisation of 3-mercaptopyruvate sulfurtransferase from the liver of fruit bat (eidolon helvum)(Department of Biochemistry and Molecular Biology, Obafemi Awolowo University, Ile Ife, Nigeria., 2024) Alalade, Foluso Ruth.This study isolated and purified 3-mercaptopyruvate sulfutransferase (3-MST) from the liver of fruit bat (Eidolon Helvum). It also determined the physicochemical properties of 3-MST from E.helvum. These were with a view to providing information on the physicochemical properties of the enzyme. Eidolon helvum (fruit bat) were collected from the Botanical Garden, Obafemi Awolowo University, Ile-Ife, Nigeria and identified at the department of Zoology, O.A.U, Ile-Ife. The E.helvum were transported to the Enzymology Laboratory, Department of Biochemistry and Molecular Biology, Obafemi Awolowo University, Ile-Ife, Nigeria and the liver were immediately excised stored in the refrigerator until use. The liver was allowed to thaw weighed and homogenized using 3 volumes of homogenization buffer (0.1M phosphate buffer, pH 7.4). The homogenate was centrifuged at 10,000 rpm for 15 minutes at 4 ºC to remove cell debris. The supernatant was collected and assayed for 3-MST activity and protein concentration was determined following standard methods. Purification of the enzyme from Eidolon helvum was carried out using ammonium sulphate precipitation, ion exchange chromatography on CM Sephadex C-50 cation exchanger and Sephadex G-100 gel filtration chromatography. The native molecular weight of the purified 3- mercaptopyruvate sulfurtransferase was determined using Sephadex G-100 while the subunits molecular weight of the purified 3-mercaptopyruvate sulfurtransferase was determined using SDS PAGE. The purified enzyme was further characterized by determining the effects of pH and temperature (optimum and stability). The kinetic parameters, substrate specificity (using sulphur compounds), effects of inhibitors and effects of metals was also determined. 3-Mercaptopyruvate sulfurtransferase from the liver of E. helvum was purified with a specific activity of 11.08 U/mg, purification fold of 8.21 and % yield of 46.92. The native molecular weight and subunit molecular weight were 36.24 kda and 35.72 kda respectively. The apparent Km and Vmax values for potassium cyanide and mercaptoethanol were 8.60 ± 0.17 mM, 96.65 ± 0.56 MU/ml/min and 7.77 ± 0.42 mM, 48.02 ± 0.38 MU/ml/min respectively. The optimum temperature and pH were 70 ºC and 7.0 respectively. Substrate specificity study involving the use of other sulphur compounds revealed that 3-MST from the liver of E. helvum showed high preference for mercaptoetanol and sodium thiosulphate. Metal salts (SnCl2, HgCl2, MnCl2, NaCl, MgCl2 and KCl) showed different degrees of inhibition of 3-MST from the liver of E. helvum. At 70 ºC, 3-MST from the liver of Eidolon helvum retained 66.67 % of its activity for 40 minutes. Urea and EDTA inhibited the activity of the 3-MST while DPPD did not affect the activity of the enzyme. The study established the presence of Mercaptopyruvate sulfurtransferase (a cyanide detoxifying enzyme) in the liver of Eidolon helvum. It further showed the physicochemical properties of 3-MST in the liver of Eidolon helvum. This could possibly be responsible for the mechanism of survival of the Eidolon helvum through cyanide detoxification in their environment.
- ItemOpen AccessComparative Assessment of Plant-Based Extracts and Synthetic Insecticides on the Growth, Yeild and Proximate Composition of Cowpea (Vigna Unguiculata L. Walp)(Department of Institute ofr Ecology and Environmental Studies, Faculty of Science, Obafemi Awolowo University., 2022) FEYINSOLAMI, Ebunoluwa adebayoThis study assessed the effect of plant-based and synthetic insecticides application on the growth response and yield of cowpea. It also investigated the effects of the insecticides application on the biomass, grain yield and proximate composition of cowpea grains produced. These were with a view to providing information on the use of plant-based extracts on quantity and quality of cowpea grains. The experiment was conducted on a vacant land measuring 11.75 m x 7.50 m behind the Institute of Ecology and Environmental Studies, Obafemi Awolowo University, Ile-Ife. Viable seeds of Ife-brown cultivar of cowpea were purchased from the Institute of Agricultural Research and Training, Ibadan. The experimental location was cleared manually two times using a cutlass and hand-held hoe. The experiment consisted of four treatments which were: extracts of three plant-based (Azadirachta indica, Tithonia diversifolia, Chromolaena odorata) and cypermethrin that served as control. The extracts of fresh shoots of A. indica, T. diversifolia, and C. odorata were separately prepared using standard method. The experiment was made up of 12 plots, each measuring 1.5 m x 2.0 m and the plots were arranged in a randomized complete block design. Four seeds per stand were sown using 50 cm x 30 cm spacing and seedlings thinned to 2 stands per hole at 2 weeks after sowing (WAS). The plots were weeded at 3 and 6 WAS. The cowpea stands were sprayed with plant-based and cypermethrin using the rates 100 g/L/plot and 15 mL/L/plot respectively at 5, 6, 7 and 8 WAS. Growth parameters such as plant height, number of leaves and stem girth were measured bi-weekly from 2 to 8 WAS and extent of leaf damage at 7 and 8 WAS. Tagged cowpea stands were carefully uprooted at 10 WAS to determine the total biomass yield. Cowpea pods were harvested when the pods turned yellow at 10 WAS and threshed. Proximate composition of cowpea grains (crude protein, ash, fibre, carbohydrate, fat and dry matter), pre- xv and post-cropped soil analyses were carried out using standard methods. Data obtained were subjected to analysis of variance and their treatment means were separated using Tukey’s multiple comparison test at p < 0.05. The results showed that pH of the pre-cropped soil was 6.94 and soil texture was loamy sand. Organic carbon and total nitrogen were 0.64 and 5.82 g/kg, respectively and these values reduced to between 13 and 30% across the treatment plots for the post-cropped soil. The growth parameters; height (cm), number of leaves and stem girth (cm) at 6 WAS were: 23.06 ± 0.86, 55.29 ± 4.59 and 1.58 ± 0.05 for A. indica; 24.15 ± 0.75,57.58 ± 3.94 and 1.69 ± 0.06 for T. diversifolia; 21.76 ± 0.68, 48.38 ± 2.15 and 1.55 ± 0.05 for C. odorata; and 21.99 ± 1.18, 45.26 ± 3.45 and 1.46 ± 0.07 for cypermethrin, respectively. Also, the grain yield of cowpea with cypermethrin, 1.08 t/ha was significantly (p < 0.05) higher than the best plant-based insecticide, T. diversifolia. Cowpea grains obtained with T. diversifolia and C. odorata had comparable and high values of crude protein (29.7%, 28.3%) and fibre (6.1%, 6.5%) respectively. The study concluded that T. diversifolia compared favourably with cypermethrin, in terms of grain yield of cowpea, whereas T. diversifolia and C.