title: Optimization of adsorptive immobilization of alcohol dehydrogenases.
abstract: In this work, a systematic examination of various parameters of adsorptive immobilization of alcohol dehydrogenases (ADHs) on solid support is performed and the impact of these parameters on immobilization efficiency is studied. Depending on the source of the enzymes, these parameters differently influence the immobilization efficiency, expressed in terms of residual activity and protein loading. Residual activity of 79% was achieved with ADH from bakers' yeast (YADH) after optimizing the immobilization parameters. A step-wise drying process has been found to be more effective than one-step drying. A hypothesis of deactivation through bubble nucleation during drying of the enzyme/glass bead suspension at low drying pressure (<45 kPa) is experimentally verified. In the case of ADH from Lactobacillus brevis (LBADH), >300% residual activity was found after drying. Hyperactivation of the enzyme is probably caused by structural changes in the enzyme molecule during the drying process. ADH from Thermoanaerobacter species (ADH T) is found to be stable under drying conditions (>15 kPa) in contrast to LBADH and YADH.
authors.affiliation: Biochemical Engineering, RWTH Aachen University, Worringerweg 1, Sammelbau Biologie, 52056 Aachen, Germany.
authors.forename: Archana
authors.initials: A
authors.lastname: Trivedi
authors.forename: Matthias
authors.initials: M
authors.lastname: Heinemann
authors.forename: Antje C
authors.initials: AC
authors.lastname: Spiess
authors.forename: Thomas
authors.initials: T
authors.lastname: Daussmann
authors.forename: Jochen
authors.initials: J
authors.lastname: Büchs
mesh_terms: D000327:Adsorption; D000426:Alcohol Dehydrogenase / Q000032:analysis* / Q000737:chemistry*; D020099:Coated Materials, Biocompatible / Q000032:analysis / Q000737:chemistry*; D003890:Desiccation; D004789:Enzyme Activation; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry*; D007778:Lactobacillus / Q000201:enzymology*; D011312:Pressure; D011485:Protein Binding; D011786:Quality Control; D013045:Species Specificity; D046968:Thermoanaerobacter / Q000201:enzymology*
chemical_list: D020099:Coated Materials, Biocompatible; D004800:Enzymes, Immobilized; D000426:Alcohol Dehydrogenase