Effect of Temperature on the Growth and Cell Wall Chemistry of a Facultative Thermophilic Bacillus

The morphology and cell wall composition of Bacillus coagulans, a facultative thermophile, were examined as a function of growth temperature. The morphology of the organism varied when it was grown at different temperatures; at 37 C the organism grew as individual cells which increased in length with increasing growth temperature. At 55 C it grew in long chains of cells. Cell wall prepared from cells grown at 37 C contained 44% teichoic acid by weight, whereas cells grown at 55 C contained 29% teichoic acid. Teichoic acid from these cells was a polymer of glycerol phosphate containing galactose and ester alanine. The ratio of ester alanine to phosphate was significantly higher in cell walls and teichoic acid from 37 C-grown cells compared with those from 55 C-grown cells. Other differences observed were that cells grown at 55 C contained a lower level of autolytic ability, produced cell walls which bound more Mg(2+), and contained less peptide cross-bridging in its peptidoglycan layer than cells grown at 37 C.