Optimising orifice geometry for selective release of periplasmic products during cell disruption by hydrodynamic cavitation

Downstream processing accounts for a large proportion of the manufacturing cost of biopharmaceutical products. One of the several approaches to improve the process economics include reducing the amount of contaminants and micronised cell debris in the product stream that is presented to the secondary purification steps. We have reported a detailed study on the use of hydrodynamic cavitation and its distinctive capacity to release periplasmic products with higher selectivity compared to other conventional mechanical methods of cell disruption. In the current study, the influence of orifice geometry on selective release of periplasmic proteins is presented. The amount of shear in the system is varied through changing the geometry of the orifice plate, in terms of shape, size and number of orifices used for generating cavities. For a constant intensity of cavitation, of the various shapes studied circular orifice that permits higher number of jet stream from the orifice plates and thus higher shear was found to be advantageous in releasing periplasmic products selectively from E. coli. (C) 2011 Elsevier B.V. All rights reserved.