ENHANCED DISRUPTION OF CANDIDA-UTILIS USING ENZYMATIC PRETREATMENT AND HIGH-PRESSURE HOMOGENIZATION

The enhancement of the overall disruption of a native strain of Candid a utilis (ATCC 9226) was studied using a combination of two methods, n amely, pretreatment in the form of partial enzymatic lysis by Zymolyas e followed by mechanical disruption in a Microfluidizer high-pressure homogenizer. The cells were grown in both batch and continuous culture s to examine the effect of specific growth rate on disruption. Cell su spensions ranging in concentration from 7 to 120 g DW/L were disrupted with and without enzymatic pretreatment. For yeast grown in batch cul ture, final total disruption obtained using the combined protocol appr oached 95% with four passes at a pressure of 95 MPa, as compared with only 65% disruption using only mechanical homogenization. A modified m odel was developed to predict the fraction disrupted by the enzymatic pretreatment-mechanical homogenization two-stage process. Predicted di sruptions agreed favorably with experimental observations (maximum dev iation of 20%) over a wide range of operating conditions. (C) 1994 Joh n Wiley & Sons, Inc.