Browsing by Author "Ayinla, Zainab Adenike"

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    Biochemical and biophysical characterisation of a small purified lipase from Rhizopus oryzae ZAC3
    (Taylor and Francis Online, 2021-02-08) Ayinla, Zainab Adenike; Ademakinwa, Adedeji Nelson; Gross, Richard A.; Agboola, Femi K.
    The characteristics of a purified lipase from Rhizopus oryzae ZAC3 (RoL-ZAC3) were investigated. RoL-ZAC3, a 15.8 kDa protein, which was optimally active at pH 8 and 55 °C had a half-life of 126 min at 60 °C. The kinetic parameters using p-nitrophenylbutyrate as substrate were 0.19 ± 0.02 mM, 126 ± 5.6 U/ml and 122 s−1 for Km , V max and k cat respectively. RoL-ZAC3 showed stability in methanol and isopropanol with Na+ enhancing the activity. p-nitrophenyloleate and castor oil were the best preferred substrates among the p-nitrophenyl esters and vegetable oils tested respectively. About 43% residual activity was observed after incubation for 30 min at 75 °C. Circular dichroism thermal scan showed that the lipase displayed intense negative ellipticities even at high temperature. Perturbation of the tertiary structure with increasing temperature caused the exposure of hydrophobic side chains to the aqueous environment as revealed by tryptophan fluorescence, with a t−Tm of 50 °C. Differential scanning calorimetry analysis showed melting temperature and calorimetric enthalpy of 55.5 °C and 444 kJ/mol respectively. Dynamic light scattering analysis indicated that the lipase was prone to aggregation upon unfolding at high temperature. It can be concluded that RoL-ZAC3 possesses promising potential for numerous biotechnological applications.
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    Fungal α-amylase entrapped in agar-agar organic matrix “beads” enhances fabric starch-desizing potentials and α-amylase-detergent compatibility
    (Research Square, 2021-08-05) Ademakinwa, Adedeji Nelson; Ayinla, Zainab Adenike; Agboola, Femi Kayode
    Aureobasidium pullulans α-amylase (ApAmy) mixed with melted agar-agar solution and drop-wisely added to a mixture of organic solvent solution allowed for the entrapment of the α-amylase in the agaragar organic matrix as beads. The immobilized ApAmy’s characteristics and wash performance were elucidated in comparison with the soluble ApAmy. Agar-agar at 2.0 % (w/v) and toluene: chloroform at 3:1 resulted in the highest immobilization yield retaining about 98% residual activity after ten catalytic cycles. The optimum temperature and pH for the immobilized enzyme were 60ºC and 6.5 respectively. The immobilized ApAmy hydrolysed branched and linear substrates thus establishing its broad substrate specificity. Relatively, the immobilized ApAmy (iApAmy) was more tolerant to organic solvents than the free enzyme. The iApAmy was mildly inhibited by cobalt but metals such as zinc, manganese, calcium and sodium enhanced the free and immobilized ApAmy activity. The iApAmy had a higher washing efficiency (77%) in the presence of detergents than the free enzyme (68%) and control (36%). The iApAmy showed good potentials as a detergent additive and from its characteristics, it could be useful in other industrial applications.
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    Production of cellulase by Mucor ramanniacus using submerged fermentation and its applications in biodegradation of agro-industrial waste
    (Research Square, 2021-03-13) Ibukunoluwa, Taiwo Dorcas; Nelson, Ademakinwa Adedeji; Ayinla, Zainab Adenike; Agboola, Femi Kayode
    This study was undertaken to isolate and identify a novel cellulase-producing strain from a waste site (7°28’11’’N 4°31’24’’E), optimise the growth conditions, partially purify and biochemically characterise the enzyme. The potentials of the puri􀂦ed cellulase to hydrolyse the lignocellulosic component of some agroindustrial wastes (e.g. orange peels etc.) was also investigated. The best cellulase-producing fungus was identi􀂦ed as Mucor ramanniacus and the optimum conditions for cellulase production were pH (4.5), inoculum size (12 mm), carbon and nitrogen sources were carboxymethyl cellulose and sodium nitrate respectively resulting in a speci􀂦c activity of 1423 Units/mg protein. A puri􀂦cation fold of 1.56 and 45.37 % yield were obtained after puri􀂦cation. The optimum pH and temperature were at 9.0 and 40°C respectively. The kinetic parameters were 0.63 ± 0.495 mg/ml, 20.21 ± 11.28 U/ml, 1001.4s− 1 for Km and Vmax and kcat respectively. Na+, K+, Ca+, Cysteine, β- mercaptoethanol and SDS were activators while Tween 80, Triton X-100 EDTA, Hg2+ and Ba2+ inhibited the enzyme. M. ramanniacus cellulase hydrolysed all agro-industrial wastes used. The partially puri􀂦ed M. ramanniacus cellulase showed great potential in biodegradation of various lignocellulosic substrates and the biochemical characteristics exhibited makes it suitable in industrial applications.
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    Purification and biochemical characterization of a β-cyanoalanine synthase expressed in germinating seeds of Sorghum bicolor (L.) moench
    (De Gruyter : Turkish Journal of Biochemistry, 2018-02-06) Amiola, Ruth Ololade; Ademakinwa, Adedeji Nelson; Ayinla, Zainab Adenike; Ezima, Esther Nkechi; Agboola, Femi Kayode
    Background: β-Cyanoalanine synthase plays essential roles in germinating seeds, such as in cyanide homeostasis. Methods: β-Cyanoalanine synthase was isolated from sorghum seeds, purified using chromatographic techniques and its biochemical and catalytic properties were determined. Results: The purified enzyme had a yield of 61.74% and specific activity of 577.50 nmol H2S/min/mg of protein. The apparent and subunit molecular weight for purified β-cyanoalanine synthase were 58.26 ± 2.41 kDa and 63.4 kDa, respectively. The kinetic parameters with sodium cyanide as substrate were 0.67 ± 0.08 mM, 17.60 ± 0.50 nmol H2S/mL/min, 2.97 × 10−1 s−1 and 4.43 × 102 M−1 s−1 for KM, Vmax, kcat and kcat/KM, respectively. With L-cysteine as substrate, the kinetic parameters were 2.64 ± 0.37 mM, 63.41 ± 4.04 nmol H2S/mL/min, 10.71 × 10−1 s−1 and 4.06 × 102 M−1 s−1 for KM, Vmax, kcat and kcat/KM, respectively. The optimum temperature and pH for activity were 35°C and 8.5, respectively. The enzyme retained more than half of its activity at 40°C. Inhibitors such as HgCl2, EDTA, glycine and iodoacetamide reduced enzyme activity. Conclusion: The biochemical properties of β-cyanoalanine synthase in germinating sorghum seeds highlights its roles in maintaining cyanide homeostasis
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    Strain improvement and statistical optimization as a combined strategy for improving fructosyltransferase production by Aureobasidium pullulans NAC8
    (Elsevier, 2017-07-04) Ademakinwa, Adedeji Nelson; Ayinla, Zainab Adenike; Agboola, Femi Kayode
    Strain improvement of a low fructosyltransferase-producing Aureobasidium pullulans NAC8 (Accession No. KX023301) was carried out using chemical mutagens such as ethidium bromide and ethyl methane sulfonate. The wild-type and mutant strain were distinguished using Random amplified polymorphic DNA PCR and DNA fingerprinting analysis. Plackett-Burman and Box Behnken design were statistical tools used to determine important media parameters and optimization, respectively. Phenotypically and genetically, the new improved strain was different from the wild-type. The most important media parameters from PDB influencing fructosyltransferase production were ammonium chloride, sucrose and yeast extract at p<0.05. Some significant parameters obtained with the BBD exhibited quadratic effects on FTase. The F values (35.37 and 32.11), correlation coefficient (0.98 and 0.97) and the percent coefficient of variation (2.53% and 2.40%) were obtained for extracellular and intracellular FTase respectively. The validation of the model in the improved strain resulted in an overall 6.0 and 2.0-fold increase in extracellular and intracellular FTase respectively compared to the wild-type. A relatively low FTase-producing strain of Aureobasidium pullulans NAC8 was enhanced for optimum production using a two-pronged approach involving mutagenesis and statistical optimization. The improved mutant strain also had remarkable biotechnological properties that make it a suitable alternative than the wild-type
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    Studies on the Optimization of Lipase Production by Rhizopus sp. ZAC3 Isolated from the Contaminated Soil of a Palm Oil Processing Shed
    (Journal of Applied Biology & Biotechnology, 2017-03-20) Ayinla, Zainab Adenike; Ademakinwa, Adedeji Nelson; Agboola, Femi Kayode
    This study investigated the screening, production and optimization of an extracellular lipase from a fungus isolated from the contaminated soil of a palm oil processing shed. This was with a view to obtaining a strain that can secrete lipase with biochemical properties exploitable for biotechnological applications such as bioremediation of oil contaminated sites. Soil samples were collected from palm oil contaminated sites in Gbogan, Osun State, Nigeria (Latitude N 7°29.1481´ and Longitude E 4°20.7587´). The isolated fungal strains were screened on tributyrin agar for exogenous lipolytic activity. Molecular identification was carried out by amplifications of ITS-1, 5.8S and ITS-2 regions. The effects of incubation time, inducers, pH, temperature, carbon and nitrogen sources were varied for optimal lipase production using one factor at a time approach. Rhizopus oryzae ZAC3 (NCBI accession No: KX035094) was identified as the highest lipase-producing strain. Maximum lipase production was observed on the fourth day, pH 5.0 and a temperature of 45 oC. Olive oil, xylose and yeast extract were the best inducer, carbon and nitrogen sources respectively for lipase production. There was a 2.02 fold increase in lipase production under these optimized conditions. In conclusion, Rhizopus oryzae ZAC3 lipase has properties exploitable for industrial and biotechnological applications