Abstract: Economical oxidation of glucose is achieved by oxidation with an immobilized glucose oxidase-catalase composition in a reaction mixture at low temperatures below 15.degree. C., preferably between 10.degree. C. and the freezing point of the reaction mixture. The immobilized glucose oxidase-catalase composition preferably contains glucose oxidase and catalase bonded to hardened protein particles with the catalase activity being at least one-sixth of the glucose oxidase activity.

Abstract: Living, fermentable yeast cells are prepared having an enzyme or mixture of enzymes coupled thereto. Enzyme coupling is carried out by contacting at least partially dehydrated living yeast cells with an aqueous enzyme solution to cause the yeast cells to rehydrate and a layer of enzyme to form on the surface of the yeast cells, and than contacting the rehydrated yeast cells with an enzyme-precipitating solution which optionally contains a cross-linking agent to cause the enzyme to become attached to the yeast cells. An aqueous solution of tannin is preferably the enzyme-precipitating solution and gluardialdehyde is preferably the cross-linking agent. Pepsin coupled to Saccharomyces yeast, when used to ferment grape must to produce wine, results in practically foam-free attenuation, quicker fermentation and better self-clarification. Saccharomyces yeast having amgloglucosidase coupled thereto may be used to ferment beer wort to produce a diet beer.

Abstract: Enzymes are immobilized by mixing an enzyme solution with a dry insoluble crosslinked protein having a water-absorption capacity of 2 to 8 times its dry weight, allowing the protein to swell and suck up the total amount of enzyme solution and mixing the enzyme-containing swollen protein with a solution of glutardialdehyde to bond the enzymes to the protein. Enzymes immobilized by this method are especially well suited for repeated and continuous use.