Shear stress induced variation of cell condition and productivity.

Anchorage-dependent recombinant BHK-21 cells, which produce beta-D-galactosidase, were subjected to shear stress levels in the range between 0.1 and 1.55 N m-2 over a period of three days. To investigate cell constitution and productivity, the cell number and viability, as well as the lactate dehydrogenase and beta-D-galactosidase activity, were determined. Low (0.25-0.75 N m-2) and intermediate (0.75-1.25 N m-2) shear stress rates stimulated; higher shear stress rates (more than 1.25 N m-2) diminished productivity. Cell number and general condition were influenced negatively by all but the lowest levels of shear stress. An optimal shear stress level between 0.4 and 0.6 N m-2 can be deduced.