title: Development of a silica monolith microbioreactor entrapping highly activated lipase and an experiment toward integration with chromatographic separation of chiral esters.
abstract: Microbioreactors are effective for high-throughput production of expensive products from small amounts of substrates. Lipases are versatile enzymes for chiral syntheses, and are highly activated when immobilized in alkyl-substituted silicates by the sol-gel method. For practical application of sol-gel immobilized lipases to a flow system, a microbioreactor loaded with a macroporous silica monolith is well suited, because it can be easily integrated with a chromatographic separator for optical resolution. We attempted to develop a microbioreactor containing a silica monolith-immobilized lipase. A nonshrinkable silica monolith was first formed from a 4:1 mixture of methyltrimethoxysilane (MTMS) and tetramethoxysilane (TMOS). It was then coated with silica precipitates entrapping lipase, derived from a 4:1 mixture of n-butyltrimethoxysilane (BTMS) and TMOS. As a result, monolith treated with the BTMS-based silicate entrapping lipase exhibited approximately ten times higher activity than nontreated monolith-immobilized lipase derived from the MTMS-based silicate, in transesterification between glycidol and vinyl n-butyrate in isooctane. A commercially available chiral column was connected in series to the monolith microbioreactor, and a pulse of substrate solution was supplied at the inlet of the reactor. Successful resolution of the racemic ester produced was achieved in the chromatographic column.
authors.affiliation: Department of Chemical Engineering, Faculty of Engineering, Kyushu University, Fukuoka, Japan. kawakami@chem-eng.kyushu-u.ac.jp
authors.forename: Koei
authors.initials: K
authors.lastname: Kawakami
authors.forename: Daisuke
authors.initials: D
authors.lastname: Abe
authors.forename: Taiki
authors.initials: T
authors.lastname: Urakawa
authors.forename: Ayako
authors.initials: A
authors.lastname: Kawashima
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Oda
authors.forename: Ryo
authors.initials: R
authors.lastname: Takahashi
authors.forename: Shinji
authors.initials: S
authors.lastname: Sakai
mesh_terms: D019149:Bioreactors; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods; D004800:Enzymes, Immobilized / Q000737:chemistry*; D004952:Esters / Q000032:analysis*; D005782:Gels / Q000737:chemistry; D008049:Lipase / Q000737:chemistry*; D015394:Molecular Structure; D055095:Optics and Photonics; D010316:Particle Size; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012822:Silicon Dioxide / Q000737:chemistry*; D013237:Stereoisomerism; D013499:Surface Properties; D013997:Time Factors
chemical_list: D004800:Enzymes, Immobilized; D004952:Esters; D005782:Gels; D012822:Silicon Dioxide; D008049:Lipase