SURFACE-PROPERTIES AND ADHESION OF BACILLUS-CEREUS AND BACILLUS-SUBTILIS TO POLYURETHANE - INFLUENCE OF GROWTH TEMPERATURE

We sought to determine the influence of the growth temperature on the surface physicochemical properties and adhesion of Bacillus cereus and Bacillus subtilis. Growth temperature did not affect the surface char acteristics of Bacillus cereus. With respect to the surface characteri stics of the bacteria, water contact angle values indicated a hydrophi lic nature for the vegetative forms of Bacillus subtilis with the exce ption of vegetative form cultured at 44 degrees C which, like the spor ulated forms of the two species, was more hydrophobic. When Bacillus s ubtilis was cultured at a temperature other than the optimum growth te mperature, its global charge was increased; the more distant the cultu re temperature from the optimum temperature (30 degrees C), the higher the negative charge. Furthermore, using a tensiometric method, we dem onstrated a production of surfactant by Bacillus subtilis. The rate of production rose the closer the growth temperature was to the optimum temperature. In line with the forecasts made on the basis of bacterial energy characteristics and those of a polyurethane surface, the growt h and adhesion temperature only had a slight influence on the number o f adherent cells.