Ein einfaches Verfahren zur Herstellung anellierter Thiophene

A simple method for the synthesis of fused thiophenes by reaction of agr-carboxymethyl substituted cyclic ketones withLawesson-reagent is described. Considerations concerning the reaction mechanism are given

Comparison Of Yarrowia Lipolytica Lipase Immobilization Yield Of Entrapment, Adsorption, And Covalent Bond Techniques

The purpose of this study was to immobilize lipase from Yarrowia lipolytica using three methods including inclusion, adsorption, and covalent bond to study enzyme leaching, storage, and catalytic properties. Sodium alginate and chitosan were the polymers selected to immobilize lipase by inclusion. The beads of each polymer were dried by freeze drying and fluidization. The results show that chitosan was more adapted to the inclusion of lipase. Even though freeze dried, bead activity was low compared to that of fluidized beads. The freeze-drying process seems to produce suitable beads for storage at 4 and 20 °C. The immobilization by adsorption was carried out on both celite and silica gel. Maximum immobilization yield of 76% was obtained with celite followed by 43% in silica gel. The enzyme adsorbed on the two supports exhibited greater stability at a certain temperature (50 °C) and in no polar solvents (Isooctane, n-heptane, and n-hexane). In addition, the lipase immobilized by covalent bond retained residual activity equitable to 70%. It was demonstrated that the enzyme immobilized by covalent bond showed greater activity (80%) after 5 months of storage

Mechanism of protein release from polyelectrolyte multilayer microcapsules

10.1021/bm901450rBiomacromolecules1151241-1247BOMA