title: Comparative study of properties of immobilized lipase onto glutaraldehyde-activated amino-silica gel via different methods.
abstract: The enzyme-aggregate coating method was performed to immobilize Arthrobacter sp. lipase in order to achieve better catalytic properties comparable to the conventional covalent attachment and covalent attachment plus cross-linking. The glutaraldehyde-activated amino-silica gel which was synthesized by sol-gel technique was used as the support, and the catalytic characteristics of the lipase preparations were tested in the asymmetric acylation of 4-hydroxy-3-methyl-2-(2-propenyl)-2-cyclopenten-1-one (HMPC) in organic solvents. The results showed that the immobilized lipase by enzyme-aggregate coating possessed both higher activity and stability than those by other methods, e.g. it obtained an activity of 82.6 U/g and remained 42% and 93% of the original activity after incubation in vinyl acetate at 60 degrees C for 16 h and 9 times recycles, respectively, while the covalently attached lipase got an activity of 67.4 U/g and left 33% and 73% of the original under the same conditions, and the enzyme prepared by covalent attachment plus cross-linking exhibited the lowest activity yield. Moreover, excellent enantioselectivity (E > or =400) was achieved by all the three prepared lipases in our paper (E=85 for the free enzyme).
authors.affiliation: Institute of Bioengineering, College of Material Science and Chemical Engineering, Zhejiang University, Hangzhou 310027, China.
authors.forename: Guang
authors.initials: G
authors.lastname: Yang
authors.forename: Jianping
authors.initials: J
authors.lastname: Wu
authors.forename: Gang
authors.initials: G
authors.lastname: Xu
authors.forename: Lirong
authors.initials: L
authors.lastname: Yang
mesh_terms: D000215:Acylation; D001173:Arthrobacter / Q000201:enzymology; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D003517:Cyclopentanes / Q000737:chemistry / Q000378:metabolism; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism*; D005976:Glutaral / Q000737:chemistry; D007700:Kinetics; D008049:Lipase / Q000737:chemistry / Q000378:metabolism*; D008956:Models, Chemical; D015394:Molecular Structure; D058428:Silica Gel; D012822:Silicon Dioxide / Q000737:chemistry*; D013237:Stereoisomerism; D013379:Substrate Specificity; D013696:Temperature; D013997:Time Factors
chemical_list: D001426:Bacterial Proteins; D003517:Cyclopentanes; D004800:Enzymes, Immobilized; C506804:allethrolone; D058428:Silica Gel; D012822:Silicon Dioxide; D008049:Lipase; D005976:Glutaral