Publication

Shear deactivation of enzymes in membrane reactors

Albert Renken
1986
Conference Papers

Abstract

The technique of ultrafiltration can be applied for the recovery of biocatalysts in discontinuous as well as continuous reaction processes. The operation of ultrafiltration membrane reactors requires establishment of a certain shear rate along the membrane surface in order to prevent pronounced concn. polarization or even a gel layer of the enzyme to occur. Such a recirculating flow exposes the enzyme to shear forces and may be responsible for enhanced catalyst deactivation. The enzyme b-galactosidase [9031-11-2] from Aspergillus niger has been examd. with respect to its stability towards hydrodynamic stress. Drastic differences in the rate of enzyme denaturation were found by applying a variety of pumps. The observations may be explained by cavitational phenomena. Membrane reactor operation showed that there exists an optimum of shearing due to the adverse effects of concn. polarization and shear denaturation on the overall loss of catalytic activity. [on SciFinder (R)]

Official source

https://infoscience.epfl.ch/entities/publication/a13bf03d-1c1b-4ee0-a6e0-6bd89bd00495

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Albert Renken
1986
Conference Papers

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/a13bf03d-1c1b-4ee0-a6e0-6bd89bd00495

About this result

Related concepts (32)

Shear stress

Shear stress (often denoted by τ (Greek: tau)) is the component of stress coplanar with a material cross section. It arises from the shear force, the component of force vector parallel to the material cross section. Normal stress, on the other hand, arises from the force vector component perpendicular to the material cross section on which it acts. The formula to calculate average shear stress is force per unit area.: where: τ = the shear stress; F = the force applied; A = the cross-sectional area of material with area parallel to the applied force vector.

Membrane technology

Membrane technology encompasses the scientific processes used in the construction and application of membranes. Membranes are used to facilitate the transport or rejection of substances between mediums, and the mechanical separation of gas and liquid streams. In the simplest case, filtration is achieved when the pores of the membrane are smaller than the diameter of the undesired substance, such as a harmful microorganism.

Membrane

A membrane is a selective barrier; it allows some things to pass through but stops others. Such things may be molecules, ions, or other small particles. Membranes can be generally classified into synthetic membranes and biological membranes. Biological membranes include cell membranes (outer coverings of cells or organelles that allow passage of certain constituents); nuclear membranes, which cover a cell nucleus; and tissue membranes, such as mucosae and serosae.

Related publications (4)

Shear deactivation of enzymes in membrane reactors

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