Immobilized Candida antarctica lipase B as an sn-1,3 regiospecific biocatalyst for the interesterification of triacylglycerols with fatty acid ethyl esters

Candida antarctica lipase B (CALB) is regarded as non-regiospecific. This study aimed to investigate the regiospecificity of CALB in the solvent-free interesterification of high-oleic sunflower oil with stearic acid ethyl ester for 1,3-distearoyl-2-oleoylglycerol (SOS)-rich fat preparation using a packed bed reactor. The content ratio of 1,2-distearoyl-3-oleoylglycerol (SSO) to SOS (denoted by SSO/SOS content) obtained using Lipozyme 435 (a commercially immobilized CALB; 0–4.1%), at residence times (1–32 min) was similar to that obtained using Lipozyme RM IM (0–3.0%), but lower than that obtained using Lipozyme TL IM (6.0–39.4%). When immobilized on Lewatit VP OC 1600, Lipozyme CALB had an SSO/SOS content of 0–10.4%, which was greater than that of Palatase 20,000 L (0–1.1%) but was lower than that of Lipozyme TL 100 L (8.8–97.7%). Our findings suggest that immobilized CALB shows distinct sn-1,3 regiospecificity in the interesterification of triacylglycerol with fatty acid ethyl esters.