Performance of d-amino acid oxidase in presence of ionic liquids

摘要

The activity and stability of free and immobilized d-amino acid oxidase (DAAO, EC 1.4.3.3) from Trigonopsis variabilis CBS 4095 in different water-soluble and water-insoluble ionic liquids (ILs) as well as in organic solvents were studied for comparison. The most promising ILs ([BMIM][BF(4)] and [MMIM][MMPO(4)]) were investigated in detail. The kinetic parameters (v(max)=187nkat/g dry weight, K(M)=1.38mM) with d-phenylalanine as substrate were calculated in 40% [BMIM][BF(4)]. Bioconversions of d/l-phenylalanine in 40% [BMIM][BF(4)] and 20% [MMIM][MMPO(4)] on a 3ml scale using immobilized DAAO were performed by addition of free catalase from Micrococcus lysodeikticus. After total conversion of substrate in presence of 20% [MMIM][MMPO(4)] the residual activity of the immobilized DAAO was 79% and 100% of the free catalase.