Gist-brocades N.v.

Johannes B Van Der Plaat

Abraham Harder

Ben R DeHaan

Marsha Cummings

Farrokh Farin

Antonius F Ligtvoet

Luppo Edens

Teresa H Pors

Immobilized water-insoluble biocatalysts in particulate form comprise living cells, particularly yeast, dispersed in a cross-linked gelling agent. An enzyme, particularly amyloglucosidase, may be co-immobilized in the particles. These particles are prepared by suspending the living cells in an aqueous solution of a gelling agent, dispersing this suspension in a water immiscible organic liquid to form a suspension in the liquid of aqueous particles comprising the living cells and gelling agent, gelling the gel and cross-linking the gelling agent. It is found that when living cells such as microbial cells and especially yeast are immobilized in this way, that surprisingly, not only is their viability retained, but the ability of yeast cells to produce ethanol under continuous fermentation conditions is significantly improved. Specific strains of Saccharomyces cerevisiae, suitable for immobilization in this way, are described.

Immobilized biocatalysts and their preparation and use

Preparation of novel immobilized biocatalysts

The oxidative deterioration of water-containing products for human consumption, e.g. beverages and oil and/or fat based products is minimized by introduction of immobilized yeast. Yeast is immobilized in and/or on a solid material which allows only very slow penetration by water. Thin layers material of such a yeast-bearing solid, e.g. paraffin, wax, can be applied to the lining of crown corks. The yeast will retain sufficient viability, even after pasteurization of the contents of a container closed with the crown cork. The yeast will minimize the oxygen concentration in the contents between the time of pasteurization and eventual consumption of the contents.

Oxygen removal with immobilized dried Saccharomyces cerevisiae

Immobilized biocatalysts

A food-grade oxygen scavenger for removing oxygen from foods and beverages in containers is prepared by immobilizing dried yeast containing at least 92% dry matter in a solid material such as wax or paraffin. The solid material allows for very slow penetration of water and permits the yeast to contact only water that penetrates therethrough. The immobilized yeast is coated on an inside surface of a container or on a surface of a closure such as a stopper that is on the inside of the container when closed. After adding a food or beverage and closing the container, the immobilized yeast removes oxygen from the container. The closed container and its contents can be pasteurized and the yeast retain sufficient viability to remove oxygen.

Dry yeast immobilized in wax or paraffin for scavenging oxygen

Yeast package

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Leiderdorp, Netherlands

Johannes B Van Der Plaat