Selectivity of R-α-monobenzoate glycerol synthesis catalyzed by Candida antarctica lipase B immobilized on heterofunctional supports

•The stereoselectivity of CALB was modified by the support and its functionalization.•Heterofunctional silica allowed obtaining the most stereoselective biocatalyst.•Silica biocatalysts were the most active and stable in organic solvents.

The main goal of this work was to study different strategies of immobilization of Candida antarctica lipase B (CALB) in order to evaluate changes in the selectivity of this enzyme when R-α-monobenzoate glycerol (R-α-MBG) is obtained through of asymmetric esterification. CALB was immobilized on sepharose and silica functionalized with octyl groups (monofunctional supports) and undecanol–glyoxyl and octyl-epoxide groups (heterofunctional supports). Our results showed that the enzyme could be immobilized by all carriers, with activity yields ranging from 52% to 83%. CALB immobilized on silica octyl was the most active (367 IU g−1biocatalyst) with immobilization yields in terms of protein and expressed activity of 72% and 50% respectively and exhibited a higher half-life in 100% 1,4-dioxane at 50 °C (85,000 h). In contrast, CALB immobilized on heterofunctional silica support was the most selective biocatalyst, reaching an enantiomeric excess of 99% of R-α-MBG in 100% 1,4-dioxane. In terms of configuration the sepharose biocatalysts results in a S-enantiomer, while silica biocatalysts results in a R-enantiomer. The catalysis of asymmetric esterification of glycerol with benzoic acid to obtain R-α-MBG by CALB immobilized in heterofunctional silica is highly selective and, to our knowledge, is the most selective reported to date.

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