Key Information for the Rational design of a biocatalyst based on immobilized CALB onto nanostructured SiO2

LLERENA-SUSTER, C.R.; TOLEDO, M.V.; MATKOVIC, S.R.; MORCELLE, S. R.; BRIAND, L.E.

Catalysts

MDPI

Año: 2023

2073-4344

The adsorption of the lipase B from Candida antarctica (CALB) over nanostructured SiO2 (Ns SiO2 from now on) with and without the addition of polyols (sorbitol and glycerol) was investigated. The isotherms of adsorption allowed to establish that the maximum dispersion limit was 0.029 µmol of protein per surface area unit of Ns SiO2 (29.4 mg per 100 mg of support) which is reached in 30 min of exposure. The studies through SDS-PAGE of the immobilization solutions and infrared spectroscopy of the prepared solids determined that CALB (from a commercial extract) is selec-tively adsorbed, modifying its secondary structure distribution. Its biocatalytic activity was corroborated through the kinetic resolution of rac-ibuprofen. Conversions up to 70 % and 52 % enantiomeric excess towards S-ibuprofen in 24 hs of reaction at 45 °C were achieved. The biocat-alytic performance increased with the increase of protein loading until levels off at 0.021 µmol.m-2 reaching 0.6 µmol.min-1. The biocatalyst containing the lipase at the maximum dispersion limit and co-adsorbed polyols presented the best catalytic performance in the kinetic resolution of rac-ibuprofen, an improved thermal resistance (up to 70 °C), and stability under long-term storage (more than 2 years)