Study of substances released by ultrasonic treatment from Bacillus stearothermophilus spores

Abstract

P. PALACIOS. J. BURGOS, L. HOZ, B. SANZ AND J.A. ORDÓÑEZ. 1991. Spore heat resistance is reduced when combined ultrasonic and heat treatments are applied. To explain this phenomenon the substances released from Bacillus stearothermophilus spores to the surrounding aqueous medium by the ultrasonic treatment (20 kHz, 120 W, 12°C, 30 min) were studied. Calcium, dipicolinic acid and a glycopeptide of 7 kDa molecular weight were detected in the ultrasonicated medium. Fatty acids, acyl glycerols and glycolipids (but no phospholipids) were also released. The decrease of heat resistance induced by the ultrasonic treatment was attributed to the release of low molecular weight substances from the spore protoplast with consequent modification of its hydration state.