Biocatalytic production of new antioxidant compounds and the characterization of their antioxidant effects

Abstract

Antioxidants are an important class of compounds that quench reactive free radical intermediates formed during oxidative reactions. They prevent oxidative reactions in food and protect biological tissues against oxidative damage. Plant phenols and phenolic acids are increasingly becoming a subject of intensive research due to their bioactive properties such as antioxidant, anti-mutagenic, anti-viral and anti-inflammatory activity. Modification of the structure of natural phenolic compounds can be achieved through the use of enzymes in biocatalysis reactions with the potential to enhance the antioxidant capacity of these natural phenolic compounds. The work reported here employed the oxidative enzyme, laccase from Trametes pubescens, in the modification of the antioxidant phenolic molecules, ferulic acid and 2,6-dimethoxyphenol (2,6-DMP) as a way of enhancing their antioxidant capacity. In addition, various phenolic compounds were focused upon for coupling reactions, with the aim to increase the antioxidant capacity of the compounds. The T. pubescens strain was cultured in a 4L airlift reactor and extracellular laccase production was monitored using the standard ABTS assay. The enzyme was isolated and purified from the culture filtrate once optimal enzyme production was detected. The enzyme was purified using standard ammonium sulphate precipitation and dialysis.