Release of dipicolinic acid from spores of Geobacillus stearothermophilus

Abstract

The effect of eight pH suspensions (2, 4, 6, 7, 8, 10, 12 and 14) and four heating times (5, 15, 30 and 60 minutes) on the release of dipicolinic acid (DPA) from spores of Geobacillus stearothermophilus was evaluated. The pattern of DPA release from spores of the bacterium exhibited two peaks, one at pH 4 (41.75 ug/mL) and the second at pH 7 (43.25 ug/mL). One-way ANOVA showed that the DPA released at pH 4 and pH 7 was significantly higher as compared to other pH DPA values (p<0.05). Maximum release of the acid from the spores of G. stearothermophilus was achieved after 30 minutes of autoclaving at 121 °C. The maximum level of DPA obtained was 177 ug/mL which was four times higher as compared to the maximum DPA released in the pH experiment. One-way ANOVA showed that the DPA released after 30 minutes autoclaving was significantly higher as compared to DPA released in other heating times (p<0.05). Basing from the result obtained in the study of Rotman and Fields (1969), the variant that was used in this exercise was the smooth type because of the comparable peak of DPA at pH 7 and lower heat resistant with maximum release of DPA after 30 minutes of autoclaving at 121 °C.
 Keywords: Dipicolinic acid, Geobacillus stearothermophilus, spores, temperature, pH