Search academic texts

Information × Registration Number 0224U033051, (0123U103201) , R & D reports Title Bicatalytic systems based on oxidoreductases for "green" aerobic oxidation processes popup.stage_title Лакказо-медіаторні системи для процесів окислення субстратів з відновлювальної рослинної сировини Head Shendryk Oleksandr M., Доктор хімічних наук Registration Date 16-12-2024 Organization Vasyl' Stus Donetsk National University popup.description1 The project aims at developing new ecological processes for the oxidation of natural and synthetic compounds using enzyme-organic catalysts and a "green" oxidiant – molecular oxygen. Combined catalytic systems involved laccases and low molecular weight mediators – organic compounds with a NOH moiety (oximes, N-hydroxyimides), stable aminoxyl radicals, and natural mediators of the phenolic type – will be investigated. The systems under study will be used in the processes of oxidation of substrates from reducing plant raw materials (lignin model compounds, terpenes, furan derivatives), as well as for the complex oxidative degradation of wastewater pollutants, such as synthetic dyes, agrochemicals, and explosives. The generalization of the results obtained within the framework of integral mechanistic models will make it possible to propose new principles and approaches to the rational design of "green" enzyme-organic catalytic systems. popup.description2  The process of 4-MeO-benzyl alcohol oxidation using a green oxidoreductase/NOH-type redox mediator catalytic system was studied. Benzyl alcohols are monomeric model non-phenolic compounds of lignin; their enzyme-catalyzed oxidation is used to simulate the oxidative transformation of lignin. Commercially available universal enzymes, such as Trametes versicolor fungal laccase and plant horseradish peroxidase, were selected for a comparative study. The results indicate that peroxidase is a more effective enzyme for the oxidation of 4-MeO-benzyl alcohol to the corresponding benzaldehyde compared to laccase. Optimization of the process, including selection of temperature, reaction time, pH, organic solvent, enzyme concentration, mediator, substrate, made it possible to propose a protocol for the oxidation process occurring under mild conditions with a benzaldehyde yield of up to 87% (selectivity 100%) within 1 hour. The efficiency of aryl-substituted N-hydroxyphthalimides as redox mediators in the process of 4-MeO-benzyl alcohol oxidation was monitored. The influence of such mediator properties as redox potential, steric characteristics, stability of corresponding radicals, their activity in HAT reactions and global electrophilicity indices was analyzed. The most active mediator was 4-MeO-NHPI. The study can become the basis for further improvement of the mediator structure and creation of more effective enzyme-mediator systems for important biocatalytic protocols. Product Description popup.authors Hordieieva Iryna O. Kushch Olha V. Pukhno Natalia H. Sirobaba Serhii I. popup.nrat_date 2024-12-16 Close