Browsing by Author "Ajijolakewu Kamoldeen Abiodun"
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Item Amylase production from cassava powder by Penicillium chrysogenum in a submerged fermentation of cassava powder.(Biotechnology Society of Nigeria, 2012-08-26) Ajijolakewu Kamoldeen Abiodun; Sani, AlhasanPenicillium chrysogenum was grown on pure soluble starch and cassava powder as sole carbon sources in a submerged fermentation. Amylase production of P. chrysogenum in the cultures was assessed. Maximum amylase activity was obtained at the early stationary phase (after 72 hours of fermentation). The organism was found to be substrate specific: higher amylase activities were obtained when the organism was grown in a mineral salt medium supplemented with cassava powder than when pure soluble starch was used as the sole carbon source. Amylase activities increased as the cassava powder concentration increased up to 3%. Penicillial amylase had optimum activities at temperatures between 50 °C and 60 °C and pH between 5 and 6. The maximum hydrolytic period of the enzyme on cassava powder was 90 minutes, beyond which there was a repression of amylase activities. Keywords: Penicillium chrysogenum, Cassava powder Submerged fermentation, Penicillial amylase, Optimum activitiesItem Optimization of production conditions for xylanase production by newly isolated strain Aspergillus niger through solid state fermentation of oil palm empty fruit bunches(Elsevier, 2017-07-21) Ajijolakewu Kamoldeen Abiodun; Cheu Peng Leh; Wan Nadiah Wan Abdullah; Chee keong LeeResponse surface (RSM) optimization of selected cultural parameters and the effect of various nitrogen sources on xylanase production by novel strain of Aspergillus niger via solid state fermentation of oil-palm-empty-bunches (OPEFB) were assessed. The newly isolated oil-palm-field-domiciled strain of Aspergillus niger was identified based on rRNA analysis as Aspergillus niger USM SD2 (GenBank accession no. KU882054). RSM was used to generate regression model for xylanase activity by this organism; while the effect of non-inclusion of incubation period among selected cultural conditions was assessed based on the xylanase production profile of the organism after optimization. Results showed that optimization model terms were significant with regression coefficient (R2) value of 0.95. Xylanase activity was optimum at 25 °C, initial moisture-substrate ratio 4:1; pH 6.3 and total inoculums size, 2 × 106 spores/ml. At optimum production period, xylanase production was enhanced by more than 100% of its value prior optimization. Moreover, the use of yeast extract (Y/E) enhanced xylanase production better than any other nitrogen sources evaluated. Consequently, at its optimum concentration (15 g/l), the addition of Y/E enhanced xylanase production such that final activity (3246 IU/gds) was 160% and 29% higher than activities (1250 IU/gds) prior to and after (2512 IU/gds) parametric optimization respectively. Further analyses also showed that xylanase production by A. niger USM SD2 was independent of period of incubation and, hence, its growth rate.Item Structural Characterization and Evaluation of Mycogenic Zinc Oxide Nanoparticles from the Cell-Free Culture Extract of Aspergillus niger(Faculty of Science, Obafemi Awolowo University, 2024-04-26) Ajijolakewu Kamoldeen Abiodun; Kazeem Muinat O; Dovia Gyeyock M; Adebayo Ismail A; Ajide-Bamigboye Nimat TAdvances in the biological synthesis of nanoparticles have attracted decisive research attention in recent years. This is due to their eco-friendliness, nontoxicity and large spectra of applications. In this work, the structural characteristics and the purity of biogenic zinc oxide (ZnO) nanoparticles were assessed. Zinc oxide (ZnO) nanoparticles were synthesized extracellularly using the culture filtrate of Aspergillus niger, in the presence of zinc acetate dihydrate, as a precursor. The structural characteristics and purity of the nanoparticles were examined using standard characterization methods viz UV-visible spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier-transmission infrared (FT-IR) spectroscopy and X-ray diffraction (XRD). Results revealed a peak at 311nm and whitish and spherical particles with particulate sizes between 30 and 40 nm for the UV- -1 visible spectroscopy and SEM respectively. On the FT-IR scale, absorption peaked at 548 cm in the spectra region known for the functional groups of ZnO nanoparticles; while the average crystalline size was 21 nm based on XRD analysis. Findings in this study revealed that the ecofriendly biogenic nanoparticles synthesized by common fungi, such as Aspergillus niger, possess desirable qualities comparable to those from non-ecofriendly and costly chemical processes, which are currently employed for an array of applications