Biocatalytic processes are suitable for the development of sustainable production, as they follow the principles of green chemistry, such as waste reduction, energy efficiency, low toxicity, the use of safe solvents, mild and safe reaction conditions, and the use of catalysts. However, the implementation of biocatalytic processes in industry is often limited by the low solubility of organic substrates in water, which makes the search for suitable alternative solvents extremely important in this field.
In this master's thesis, we investigated solvents suitable for the oxidation of tyrosol acetate with laccase to produce a magnolol derivative, a potential drug for diabetes treatment. We studied the influence of different solvents on substrate solubility and enzyme activity, and we optimized the reaction conditions to achieve the highest possible conversion and selectivity of the reaction. Initially, the reaction was performed in a biphasic system (buffer/ethyl acetate), and later also in monophasic systems with various co-solvents.
The results showed that the most suitable solvents were acetate buffer with propylene glycol and acetate buffer with acetone, as they provided high enzymatic activity and good substrate solubility. Additionally, we demonstrated that the solvent influences the selectivity of the reaction: in the presence of ethyl acetate, propylene glycol, and acetone, the predominant product was 1-,1′-dityrosol-8,8′-diacetate, while the addition of octanoic acid led to the formation of more (7-oxo-6,7-dihydrodibenzo[b,d]furan-2,9a(5aH)-diyl)bis(ethane-2,1-diyl) diacetate.
In systems with co-solvents, we observed a greater loss of mass of soluble products due to the precipitation of side products. The reaction in acetate buffer with acetone was also performed in a microflow segmented flow system, where similarly to the batch system, 1-,1′-dityrosol-8,8′-diacetate was the predominant product.
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