CALB Immobilized onto Magnetic Nanoparticles for Efficient Kinetic Resolution of Racemic Secondary Alcohols: Long-Term Stability and Reusability

• Main Authors: Xiu Xing, Jun-Qi Jia, Jing-Fan Zhang, Zi-Wen Zhou, Jun Li, Na Wang, Xiao-Qi Yu
• Format: Article
• Language: English
• Published: MDPI AG 2019-01-01
• Series: Molecules
• Subjects: CALB; magnetic nanoparticles; cross-linked enzyme aggregates; resolution; secondary alcohols
• Online Access: https://www.mdpi.com/1420-3049/24/3/490

In this study, an immobilization strategy for magnetic cross-linking enzyme aggregates of lipase B from <i>Candida antarctica</i> (CALB) was developed and investigated. Magnetic particles were prepared by conventional co-precipitation. The magnetic nanoparticles were modified with 3-aminopropyltriethoxysilane (APTES) to obtain surface amino-functionalized magnetic nanoparticles (APTES&#8315;Fe₃O₄) as immobilization materials. Glutaraldehyde was used as a crosslinker to covalently bind CALB to APTES&#8315;Fe₃O₄. The optimal conditions of immobilization of lipase and resolution of racemic 1-phenylethanol were investigated. Under optimal conditions, esters could be obtained with conversion of 50%, enantiomeric excess of product (ee_p) &gt; 99%, enantiomeric excess of substrate (ee_s) &gt; 99%, and enantiomeric ratio (E) &gt; 1000. The magnetic CALB CLEAs were successfully used for enzymatic kinetic resolution of fifteen secondary alcohols. Compared with Novozym 435, the magnetic CALB CLEAs exhibited a better enantioselectivity for most substrates. The conversion was still greater than 49% after the magnetic CALB CLEAs had been reused 10 times in a 48 h reaction cycle; both ee_s and ee_p were close to 99%. Furthermore, there was little decrease in catalytic activity and enantioselectivity after being stored at &#8722;20 &#176;C for 90 days.