Browsing by Author "Kareem Sarafadeen Olateju"

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    Ascorbic Acid Production by Aspergillus flavus and Aspergillus tamarii; Kinetic and Thermodynamic Study
    (Springer, 2020) Banjo Temitope Temitayo; Kareem Sarafadeen Olateju; Adeogun Abideen Idowu
    This study investigated the fermentation kinetics and thermodynamics of ascorbic acid production from Brewery Spent Grain (BSG) using Aspergillus flavus and Aspergillus tamarii. Ascorbic acid fermentation of A. flavus and A. tamarii was performed at a temperature of 30 °C, agitation speed of 100 rpm and pH 5.0 at 96 h of fermentation. The thermodynamics, kinetics of the growth parameters and ascorbic acid production were studied using Monod, Contois and Teisser models. Teisser model gave the best fit as it obtained the highest maximum specific growth rate (μmax) and correlation coefficient of 0.184 h−1 and 0.997, respectively, at 40 °C, pH 5.0 and 0.6 g of BSG. The result showed that Teisser model gave a better description of each growth parameter. Hence, the production of ascorbic acid by A. flavus and A. tamarii is growth-associated.
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    Biosynthesis of Ascorbic Acid by Aspergillus Flavus and Aspergillus Tamarii Immobilized in Afzelia Africana Matrix.
    (Food and Applied Bioscience Journal, 2018) Banjo Temitope Temitayo; Kareem Sarafadeen Olateju; Akinloye Oluseyi Adeboye; Popoola Temitope
    A novel matrix for the immobilization of ascorbic acid produced by Aspergillus flavus and Aspergillus tamarii was reported. Spores of A. flavus and A. tamarii were immobilized on Afzelia africana matrix cross-linked with glutaraldehyde (2.5%) and the effects of Afzelia africana gel concentration (9–13%), spore load (100–500 mg/100 ml), bead size (2–7 mm) and bead number (2–10) on ascorbic acid yield were determined. The immobilized fungi were cultured in a liquid fermentation medium containing BSG (0.6% w/v) for ascorbic acid production for 144 h. The ascorbic acid produced was quantified titrimetrically. The statistical analysis of the effects of gel concentration, spore load and bead size on ascorbic acid production showed no significant difference at p>0.05. However, there was significant difference in the effect of bead number on ascorbic acid production at p<0.05. Ascorbic acid yield of 8.5 g/L and 7.5 g/L was produced by Aspergillus tamarii and Aspergillus flavus respectively using 9 beads at 96 h of fermentation. The immobilized Aspergillus tamarii and Aspergillus flavus retained activities of 72% and 70% respectively after five repeated cycle and also exhibited increased activities over the free cells. This study shows the potential of Afzelia africana as a novel matrix for enhanced ascorbic acid production.
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    Microbial Production of Ascorbic Acid from Brewery Spent Grain (BSG) by Aspergillus flavus and Aspergillus tamarii
    (Food and Applied Bioscience Journal, 2018) Banjo Temitope Temitayo; Kareem Sarafadeen Olateju; Akinloye Oluseyi Adeboye
    This study evaluated the use of Brewery Spent Grain (BSG) as a novel substrate for the production of ascorbic acid using Aspergillus flavus and Aspergillus tamarii. Spores of Aspergillus flavus and Aspergillus tamarii were cultured in a liquid fermentation medium containing BSG (0.6% w/v) for ascorbic acid production. The process was studied at pH 4–8, temperature range 30–45°C, agitation speed range 60–160 rpm for 168 h. Stability studies and the effects of Ethylenediaminetetraacetic Acid (0.5–4.0 g/ml) on ascorbic acid production were studied. Ascorbic acid produced was quantified by titration techniques and with High Performance Liquid Chromatography (HPLC). The statistical analysis of the effects of temperature and agitation speed on ascorbic acid production showed no significant difference at p<0.05. However, there was significant difference in the effect of pH on ascorbic acid production at p<0.05. Optimum ascorbic acid yields of 7.25 g/L and 6.25 g/L were produced by A. tamarii and A. flavus respectively at pH 5.0, temperature (40°C) and agitation speed of 100 rpm at 96 h of fermentation. High Performance Liquid Chromatography (HPLC) showed that 6.248 g/L and 7.246 g/L of ascorbic acid were produced by A. flavus and A. tamarii, respectively. Ascorbic acid production by A. flavus and A. tamarii was completely inhibited at 4 g/ml of EDTA. This study shows the potential of BSG as a novel substrate for ascorbic acid production.
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    Optimization and production of ascorbic acid by fusant cell of Aspergillus flavus and Aspergillus tamarii
    (Journal of King Saud University – Science, 2019) Banjo Temitope Temitayo; Kareem Sarafadeen Olateju; Akinduti Akinniyi Paul; Temitope Popoola; Akinloye Oluseyi Adeboye
    Ascorbic acid is an essential vitamin for the optimal growth of most animals including humans. The complexity and expensive nature of ascorbic acid production necessitates the development of a relatively simple and cost-effective method for its production. Hence, this study explored the potential of a somatic hybrid (fusant cell) of Aspergillus flavus and Aspergillus tamarii for enhanced production of ascorbic acid. Optimization studies of the ascorbic acid fermentation processes were performed at pH range of 4–8, temperature range of 30–45 C and agitation speed range 60–160 rpm for 96 h of fermentation. Quantification of the ascorbic acid produced was done titrimetrically. There was significant difference (P < 0.05) in the ascorbic acid production of the fusant cell and the parental cells. The ascorbic acid produced by the somatic hybrid was 8.85 g/L compared to its parental strains (3.92 g/L and 4.57 g/L). However, pH, temperature and agitation speed had no significant effects (P > 0.05) on ascorbic acid production. The study revealed that maximal ascorbic acid production of 9.95 g/L was obtained at pH 5.0, temperature 40 C and agitation speed of 100 rpm at 96 h of fermentation. This study shows the potential of fusant cell for enhanced ascorbic acid production.
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    Optimization of Biodiesel Production from Spent Cooking Oil by Fungal Lipase Using Response Surface Methodology
    (Nigerian Journal of Biotechnology, 2018) Banjo Temitope Temitayo; Kareem Sarafadeen Olateju; Adio Olayinka Quadri; Osho Michael Bamitale; Omeike Sunday Osaizua
    This study evaluated the potential of optimizing Spent Cooking Oil (SCO) transesterification for biodiesel production using Response Surface Methodology (RSM). Potential biodiesel yield from transesterification was optimized using a three-level four factor Response Surface Central Composite Design (RSCCD) with methanol oil ratio (1:1 to 3:1), temperature range 35-45 °C, agitation speed range 100-200 rpm and enzyme load 10-20%. Biodiesel properties including fatty acid methyl ester (FAME), Flash Point (FP), Pour Point (PP) and kinematic viscosity were compared with American (ASTM D6751) and European Union (EN 14214) standards. Biodiesel production was optimum at 3:1 methanol to oil ratio, temperature of 35 °C, agitation speed of 150 rpm and 20% enzyme load. 9-octadecanoic acid hydroxyl methyl ester (33.83%) was the prominent FAME produced, while the viscosity (6 mm2/s), density (893 kg/m3), FP (260 °C) and PP (- 0.5 °C) all met both American and European standards. This study showed that RSM is a viable methodology which could be used for optimization of biodiesel production from biological sources.