[Effect of the cultivation temperature on the production of biomass and lipopolysaccharide as well as the chemical composition and antigenicity of the lipopolysaccharide of S-forms and R-mutants of the genus Salmonella].

Abstract

The effect of different temperatures (30 to 43 degrees C) on Salmonella S forms and R mutants in fermentor mass cultures was studied. It was found that for the velocity of substrate utilization, for maximum LPS biosynthesis as well as for maximum biosynthesis of bacterial cell-mass the respective optimum temperature was different. In the case of S-form strains and of one SR mutant a cultivation temperature of 34 degrees C proved optimum for maximum yield of LPS. At this temperature the yield of bacterial cell-mass was only somewhat lower than that obtained at 37 degrees C. Also the cultivation time necessary although longer, remained within tolerable limits. In the case of R mutants maximum yields of bacterial cell-mass were obtained at 30-34 degrees C, however, a common optimum temperature for LPS biosynthesis did not become evident. Chemical and serological analysis of the LPS revealed that neither the pattern of fatty acids in lipid A nor O-antigen factors, 1, 5 and 12(2) were influenced in any way by the cultivation temperature in the range of 30-34 degrees C. Similarly no temperature-dependent changes in the antigenic specificity of monospecific R mutants were seen. In contrast the growth temperature had a marked influence on the number of repeating units in the O-polysaccharide and also on the number of LPS molecules with free core stubs (R form LPS) occurring in isolated S form LPS. Further in the case of a double mutant, the growth temperature had some influence on the expression of one of the R specificities.