A SIMPLIFIED MODEL FOR THE DISRUPTION OF ESCHERICHIA-COLI - THE EFFECT OF CELL SEPTATION

A new model for the disruption of Escherichia coli by high-pressure ho mogenization has been previously presented. Initial model development assumed a bimodal distribution of effective cell strengths to allow fo r a possible difference in strength between septated and nonseptated c ells. A considerably simpler model is obtained when any difference in strength is neglected and a normal distribution is employed. In this a rticle, the disruption of a culture with an abnormally high septated f raction is examined. Disruption versus pressure curves are predicted u sing both the bimodal and normal approximations to the strength distri bution. An examination of disrupted cultures by optical and electron m icroscopy suggests that septated cells are indeed weaker, thus implyin g that a bimodal approximation is strictly correct. However, compariso n of the model predictions with the experimental results suggests that the simple normal distribution provides sufficient predictive accurac y even for cultures with a high septated fraction.