Improvement of the catalytic performance of lignin peroxidase in reversed micelles

Abstract

AbstractBACKGROUND: Anionic surfactant sodium bis (2‐ethylhexyl) sulfosuccinate (AOT) had an inhibiting effect on lignin peroxidase (LiP). To improve the catalytic activity of LiP in an AOT reversed micelle in isooctane, nonionic surfactant polyoxyethylene lauryl ether (Brij30) was incorporated into the interfacial membrane. H2O2 played dual roles in the LiP‐catalyzed oxidation of substrates. To obtain a sustainable high activity of LiP, a coupled enzymatic reaction, i.e. the glucose oxidase (GOD)‐catalyzed oxidation of glucose was used as an H2O2 source.RESULTS: Owing to modification of the charge density of the interfacial membrane, the activity of LiP in an optimized AOT/Brij30 reversed micellar medium (χB (the molar percentage of Brij30) = 0.53, ω0 ([H2O]/([AOT] + [Brij30]) = 23, pH = 4.8) was 40 times that in a single AOT reversed micelle. Due to the controlled release of H2O2, the concentration of H2O2 in the mixed reversed micellar medium was maintained at a moderately high level throughout, which made the LiP‐catalyzed oxidation of substrates proceed at a higher conversion rate than counterparts in which H2O2 was supplied externally in one batch at the beginning of the reaction. Decolourization of two waterless‐soluble aromatic dyes (pyrogallol red and bromopyrogallol red) using LiP coupled with GOD in the medium also demonstrated that a higher decolourization percentage was obtained if H2O2 was supplied enzymatically.CONCLUSION: The proposed measures (both physicochemical and biochemical) were very effective, giving significant improvement in the catalytic performance of LiP in a single AOT reversed micelle in isooctane, which helped to degrade or transform hydrophobic aromatic compounds with LiP in reversed micelles more efficiently. Copyright © 2007 Society of Chemical Industry