Master of Science (M.Sc.) Theses and Dissertations
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- ItemOpen AccessProduction and purification of xylanase from a fungus isolated from a paper industry solid waste dumpsite in Osogbo,Osun State, Nigeria(Department of Microbiology, Faculty of Science, Obafemi Awolowo Universty, 2023) Salawudeen, Morufat TolaniThis study isolated and screened for xylanolytic fungi from a paper industry solid waste dumpsite. It also identified the selected fungus and then optimized the process parameters for xylanase production from selected fungus and to produced, purified as well as characterized xylanase produced from fungi isolated from a paper industry solid waste dumpsite. These were with a view to providing useful information on the potential utilization of agricultural waste as a substrate for the production of xylanase to fulfill various industrial needs. Soil samples were collected aseptically from four different location at a paper industry waste dumpsite in Osogbo, Osun State. The samples collected was processed for isolation using spread plate method and standard methods were used for characterizing and identifying the fungal isolates, which were subsequently subjected to screening using both rapid plate assay method and submerged fermentation for the process of producing xylanase. The fungus with the best xylanase activity was selected for enzyme production, purification and characterization. The best optimal conditions for xylanase synthesis by the best producing fungus were determined by varying the nitrogen sources, pH, carbon sources, temperature, inoculum volumes and different concentrations of the carbon and nitrogen sources for media composition. The best optimal condition were used for bulk synthesis of xylanase to produce the crude enzyme. The crude enzyme was partially purified using a one step purifications method of ion exchange chromatography using CM-Sephadex C-50. The effect of pH, temperature, metal ions, heat stability were studied and the kinetic parameters (Km and Vmax) of the partially purify xylanase were determined. The selected fungus, SD5, has a zones of hydrolysis and highest enzyme activity of about 12 mm and 212.30 Units/ml/min respectively from the 32 isolates obtained from the samples collected from the paper waste dumpsites after been screened. The fungus SD5 was molecularly characterized and identified as Aspergillus oryzae strain KhA0707 with 98% identity. With an inoculum amount of 1.0 ml and 4 days of fungal growth, the enzyme production reached its peak. The best optimal temperature and pH of production was 30°C and pH 6.0 respectively, while the best nitrogen and carbon sources are peptone and xylan respectively. The partially purified enzyme showed that specific activity was 5437.35 units/mg with purification fold of 12.33. Characterization of the partially purified xylanase showed that the optimum activity occurred at temperature and pH of 55 °C and 6.0 respectively. The enzyme kinetic Vmax value is 161.290 units/ml/min and Km value of 0.6129 mg/ml. EDTA totally inhibited the activity of the partially purified xylanase. The enzyme activity was slightly inhibited by Ca2+, Na+, even at 1 mM while K+, Cu2+, Al3+, urea and Mecarptopyruvate promote the xylanase activity. The findings of this research showed that a paper waste dumpsite is also a potential source for xylanolytic fungus. The isolated Aspergillus oryzae employed for xylanase production in this study was able to generate a significant quantity of xylanase, which will be useful in protein hydrolysis and industries.
- ItemOpen AccessIsolation, characterization and bioactivity studies of the extract from aerial part of hilleria latifolia (LAM)(Department of Chemistry, Faculty of Science, Obafemi Awolowo University, Ile-Ife., 2023) Arowosegbe, Sunday MichealThis study screened the crude extract of Hilleria latifolia for its phytochemical constituents and evaluated the extract and fractions for their antioxidant and antibacterial activities. It also isolated compound from its active fraction and elucidated the structure of the compound. The antioxidant and antibacterial potential of the isolated compound were also determined. These were with a view to finding novel bioactive compound from this medicinal plant. The aerial parts of the plant was air-dried and pulverized. The pulverized plant was extracted with 90% methanol/water for 96 hours and filtered. The filtrate obtained was concentrated to dryness in vacuo at 40 ℃. This afforded the crude extract which was subjected to solvent partitioning using solvents of varying polarities: n-hexane, dichloromethane and ethyl acetate in turn. This yielded four solvent fractions, and the aqueous MeOH fraction inclusive. The crude and the solvent fractions were tested for antibacterial activity, Total Phenolic Content (TPC), Total Flavonoid Content (TFC), and antioxidant activities using a number of antioxidant assays namely: 2,2-Diphenyl-1-picrylhydrazyl (DPPH), Nitric Oxide (NO) Scavenging, Metal Chelating Ability (MCA), Ferric Reducing Antioxidant Power (FRAP) and Total Antioxidant Capacity (TAC). The antibacterial activity was evaluated using the Agar diffusion method. The results showed that of all the solvent fractions obtained, the ethyl acetate fraction was the most active in the DPPH, TAC, MCA, and FRAP assays. One compound was isolated from the aqueous fraction using column chromatography. The isolated compound, HLA-1 was characterized by Nuclear Magnetic Resonance (NMR) and Infrared (IR) spectroscopy. Compound HLA-1 was identified as 8 – methyl – 1, 4 – oxazo – 2 – enine – 5, 7, 9 – trione. The n–hexane and dichloromethane fraction obtained from the crude extracts of Hilleria latifolia exhibited significant biological and antioxidant activities. These fractions were subjected to GC – MS analyses and a total of 27 compounds were identified in both fractions. Most of the identified constituents have been reported to possess various biological activities such as antioxidant, anticancer, anti-inflammatory and antibacterial activities. The study concluded that the extracts and isolated compound from Hilleria latifolia exhibited varying degree of antibacterial and antioxidant activities and could be effective in the management of infectious and oxidative stress related diseases. These observed activities could justify the ethnomedicinal uses of the plant.
- ItemOpen AccessComparative assessment of plant-based extracts and synthetic insecticides on the growth, yield and proximate composition of cowpea (Vigna unguiculata L. Walp)(Institute of Ecology and Environmental Studies, Faculty of Science, Obafemi Awolowo University., 2022) FOYINSOLAMI 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), 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. odorata gave higher proximate composition of cowpea.
- ItemOpen AccessADEBAYO E .B (2022) Comparative assessment of plant-based extracts and synthetic insecticides on the growth, yield and proximate composition of cowpea (vigna unguiculata l. walp) institute of ecology and environmental studies, Faculty of Science, Obafemi Awolowo University.(Institute of ecology and environmental studies, Faculty of Science, Obafemi Awolowo University., 2022) FOYINSOLAMI 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), preand 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. odorata gave higher proximate composition of cowpea.
- ItemOpen AccessEvaluation of insecticidal activity of pteris ensiformis (Burn.F.) against cowpea weevil, callosobruchus maculatus (Fabricius)(Department of Biochemistry, Faculty of Science , Obafemi Awolowo University Ile Ife,Nigeria., 2023) Gedia, ObanaThis study investigated the toxicity bioassay of Pteris ensiformis leaf extracts against Callosobruchus maculatus. It assessed the oviposition and adult emergency effect of the most potent extract; as well as the sublethal effect of the most potent extract on some biochemical metabolites and on the neurotransmitting, detoxifying and antioxidant enzymes in C. maculatus and profiling the constituents of the extract using spectroscopic technique. These were with a view to providing aninformation on the insecticidal potential of Pteris ensiformis leaf on C. maculatus and the constituents responsible for this property. Fresh leaves of both sterile and fertile P. ensiformis were harvested and separately air-dried and milled into fine powder with the aid of an electrical grinder. The powdered samples (100 g) of sterile and fertile P. ensiformis leaves were soaked in 300 mL of 80% ethanol and n-hexane separately at room temperature for 72 h. Each sample was then filtered after 72 h through Whatman filter paper and the filtrates were concentrat(separately) on a rotary evaporator to give the fertile ethanolic (FE), fertile hexane (FH), sterile ethanolic (SE) and sterile hexane (SH) crude extracts of P. ensiformis leaf. Acute toxicity test was conducted by inhalation over a period of 24 h using five serial concentrations (0, 1.25, 2.5, 5 and 10 mg/mL) of each of the FE, FH, SE and SH extract on filter papers using standard method. Antioviposition test as well as repellency against the weevils were carried out on each of the extracts according to standard methods. Compared to others, FE showed highest mortality, anti-oviposition and repellency activities against C. maculatus. Thus, FE LC50 was determined using probit analysis and its sub-acute toxicity study at 80%, 40% and 20% of the LC50 was conducted for 6, 12, 18 and 24 h exposure periods. The tested insects at each exposure period were homogenized in phosphate buffer and the homogenate was assayed for the following biochemical parameters: alkaline phosphatase (ALP), lactate dehydrogenase (LDH), reduced glutathione (GSH), glutathione transferase (GST), superoxide dismutase (SOD), acetylcholinesterase (AChE), acid phosphatase (ACP), glycogen and total protein. Also, the constituents of fertile P. ensiformis ethanolic leaf extract was profiled via GC-MS analysis. Analysis of data were carried out using GraphPad Prism, Statistical Analysis Software (SAS), Trimmed Spearman-Karber (TSK) program (Probit analysis), Turkey Post Test (GraphPad Software, San Diego, CA, USA). The difference were considered to be significant if p ˂ 0.05. The results indicated 11.14 mg/mL as the LC50 value for fertile P. ensiformis ethanolic leaf extract. The result further revealed different patterns of inhibition (6 and 12 hours; p ˂ 0.05) and increases (18 and 24 hours; p< 0.05) in the activities of C. maculatus ALP, LDH, GSH, and AChE (p ˂ 0.05). Additionally, at all the exposure periods, GST activity was significantly stimulated while SOD activity was inhibited. Moreover, ACP activity (p ˂ 0.05) was consistently inhibited while glycogen and protein levels increased significantly at all the exposure periods. A total of 21 compounds were identified in fertile ethanolic leaf extract of P. ensiformis with four of the components (Cis-11-Hexadecenal, Octadecanal, Ethyl 9-hexadecenoate and nHexadecanoic acid) constituting 69.17% of the total extract. The study concluded that leaves of P. ensiformis (especially sporophylls) possess insecticidal properties that could be employed in the prevention of storage infestation of cowpeas.