Patrick Adlercreutz

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Adsorption of different lipases by EP-100 polypropylene powder from crude and pure lipase preparations was studied. Langmuir isotherms described the adsorption equilibria well both for protein and lipase activity adsorption. Adsorption isotherms for five different proteins all gave a similar saturation level of 220 mg protein per g carrier. Twelve(More)
Different methods of preparing lipases for use in organic media are critically reviewed. Solid lipase preparations can be made by typical immobilisation methods such as adsorption, entrapment, covalent coupling or cross-linking. Immobilisation is especially attractive for lipases because, in addition to the normal benefits of enzyme immobilisation, it can(More)
Oxygen supply is a critical point in technical processes when aerobic cells are used in immobilized preparations. In this study p-benzoquinone is used as a substitute for oxygen in the oxidation of glycerol to dihydroxyacetone by immobilized Gluconobacter oxydans cells. The reaction rate was much higher when p-benzoquinone was used compared to when oxygen(More)
Enzymatic transglycosylation of lactose into oligosaccharides was studied using wild-type beta-glucosidase (CelB) and active site mutants thereof (M424K, F426Y, M424K/F426Y) and wild-type beta-mannosidase (BmnA) of the hyperthermophilic Pyrococcus furiosus. The effects of the mutations on kinetics, enzyme activity, and substrate specificity were determined.(More)
Catalytic activity of lipases (from Rhizopus arrhizus, Canadida rugosa, and Pseudomonas sp. was studied in organic media, mainly diisopropyl ether. The effect of water activity (a(w)) on V(max) showed that the enzyme activity in general increased with increasing amounts of water for the three enzymes. This was shown both for esterification and hydrolysis(More)
The transglucosylation reaction catalyzed by wild-type beta-glucosidase CelB from hyperthermophilic Pyrococcus furiosus and active site mutants (M424K, F426Y, M424K/F426Y) was studied. The conversion of pentyl-beta-glucoside to hexyl-beta-glucoside in hexanol was used as a model transglucosylation reaction. Hydrolysis to glucose was a side reaction. The(More)
The kinetics of the α-chymotrypsin catalysed transesterification of N-acetyl-l-phenylalanine ethyl ester with 1-butanol and the competing hydrolysis were evaluated at fixed water activity in two ionic liquids and two non-ionic organic solvents. In most respects the four solvents behaved similarly. However, at a water activity of 0.33, higher catalytic(More)
Alkyl glycosides with long carbohydrate groups are surfactants with attractive properties but they are very difficult to synthesize. Here, a method for extension of the carbohydrate group of commercially available dodecyl-beta-d-maltoside (DDM) is presented. DDM was converted to dodecyl-beta-d-maltooctaoside (DDMO) in a single step by using a CGTase as(More)
The effect of the addition of sorbitol on the activity and stability of enzymes was examined by monitoring transesterification reactions performed in organic media at various water activities (a(w) = 0.08 to 0.97). Lipases from Chromobacterium viscosum and Candida rugosa immobilized on celite, and chymotrypsin, free or immobilized on celite, were used. When(More)
The oxidation of free DHA, DHA mixed with PC, and DHA incorporated into PC, PE, or TG was evaluated to determine which lipid provided DHA with the best protection against oxidation. DHA was either situated at the sn-1 position, sn-2 position, or both positions of the phospholipid, whereas the TG contained DHA at all positions. All lipids were incubated as(More)