Browsing by Author "Machunda, RL"

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Kinetics and optimization modeling of Fenton-mediated photocatalysis of dye effluent with novel PANI/AK-TiO2 nanocomposites
(Springer Berlin Heidelberg, 2024-04-05) Oyetade, JA; Machunda, RL; Hilonga, A
The quest for the application of a high solar-photon sensitive photocatalysts for rapid photodegradation of recalcitrant dye molecules with deleterious environmental impacts remains a major setback for the adoption of photocatalysis in the treatment of industrial effluent. This brought about the development and use of a novel solar-driven photocatalyst mediated with Fenton-reagents for the treatability of dye effluent. However, the degradation efficiency of the process hinges on the reaction kinetics, synergistic or antagonistic interactive effects of three independent process variables such as the pH of the system (5–7), photocatalyst dosage (20–50 mg/L) and irradiation time (30–90 min) on the modeling and optimization photocatalysis of methylene blue dye in effluent. The result of the statistical study suggested the quadratic model which accurately predicts the response variables, having strong correlation values of 0.9984 and 0.9994 and variances < 0.2. The optimized variables for the photocatalytic process investigated by the analysis of variance were shown to be statistically significant (p-values < 0.0001), with the main interaction effects on the percentage degradation of dye being the pH, catalyst dosage, and irradiation period. Experimental optimum conditions attained were at pH = 5, dosage = 20 mg/L and irradiation time of 90 min for 97.019% degradation of methylene blue dye.
Structural characterization of cassava linamarase-linamarin enzyme complex: an integrated computational approach
(Journal of Biomolecular Structure and Dynamics, SDG 2: Zero Hunger, SDG 3: Good Health and Well-being, SDG 9: Industry, Innovation, and Infrastructure.) Lucas, Paul; Shadrack, DM; Mudogo, CN; Mtei, KM; Machunda, RL; Ntie-Kang, Fidele
Cassava linamarase is a hydrolyzing enzyme that belongs to a glycoside hydrolase family 1 (GH1). It is responsible for breaking down linamarin to toxic cyanide. The enzyme provides a defensive mechanism for plants against herbivores and has various applications in many fields. Understanding the structure of linamarase at the molecular level is a key to avail its reaction mechanism. In this study, the three-dimensional (3D) structure of linamarase was built for the first time using homology modelling and used to study its interaction with linamarin. Molecular docking calculations established the binding and orientation nature of linamarin, while molecular dynamics (MD) simulation established protein-ligand complexes' stability. Binding-free energy based on MM/PBSA was further used to rescore the docking results. An ensemble structure was found to be relatively stable compared to the modelled structure. This study sheds light on the exploration of linamarase towards understanding its reaction mechanisms.