RESUMO
The solution to the problem of optimizing conditions for the isolation of biologically active substances (BAS) from microbial cells should be based on investigations of the structural and functional characteristics of cultures. Models of two bacterial cultures, of Escherichia coli and a Xanthomonas species, producing enzymes the localization of which differ, is described. The isolation of membrane-bound penicillinamidase from E. coli was optimal in the 'preautolysis' period, when the components of the cytoplasm autolysed but the membranes remained intact. In contrast, the isolation of the cytoplasmic enzyme peptidohydrolase from Xanthomonas sp. was optimal during the period when the cell membranes markedly changed. Thus the physiological state of the cultures and the localization of the BAS within the cells are important determinants for optimization of the isolation process. It follows that all stages of a technological process for the production of BAS, i.e. biosynthesis, chemical isolation, etc., should be interrelated for a successful outcome.
