INFLUENCE OF GROWTH CONDITIONS ON COMPOSITION OF SOME CELL WALL COMPONENTS OF AEROBACTER AEROGENES

With a chemostat culture, both the bacterial growth rate and the growth environment can be independently varied between wide limits. Changing the growth rate of Aerobacter aerogenes organisms (in either a glycerol‐limited medium or a Mg2+‐limited medium) affected the bacterial cell wall content; invariably slow growing organisms were smaller than faster growing ones and had a higher cell wall/biomass ratio. Changing the growth rate also influenced the composition of the walls but in this respect glycerol‐limited organisms and Mg2+‐limited organisms behaved differently. Thus, whereas increasing the growth rate of glycerol‐limited cultures caused the cell wall 2‐keto‐3‐deoxyoctonic acid (KDO) and heptose contents to increase progressively, with Mg2+‐limited cultures they decreased. Furthermore, although KDO and heptose are both components of the lipopolysaccharide layer, their ratio varied with growth rate, and with the nature of the growth‐limitation, indicating changes in the lipopolysaccharide composition. These results are discussed with particular reference to the influence of environment on cell wall content and composition, and the use of continuous culture for the production of bacterial vaccines. Copyright © 1969 John Wiley & Sons, Inc.