LIPIDS OF BACILLUS STEAROTHERMOPHILUS ,

Abstract

Ether extraction of lyophilized cells and spores of B. stearothermophilus produced at 37[degree]C and 55[degree]C has revealed the presence of significant quantities of lipids in these entities. "Surface" extraction of intact spores yielded 6.90 to 13.11% lipid for 37[degree]C spores and 7.42 to 10.13% for 55[degree]C spores. Extraction of this lipid had no demonstrable effect upon the properties of the spores. Suggested sources of these lipids are the medium and/or lytic products of vegetative cells. Extraction of disrupted spores gave 1.48 to 1.78% total lipid for 37[degree]C samples and 1.34 to 1.88% for 55[degree]C samples. Analysis of total lipids indicated a higher lipid and lower phospholipid content of the 55[degree]C spores as compared with 37[degree]C spores. Iodine number determinations have shown the lipids of 55[degree]C spores to be highly unsaturated whereas 37[degree]C spore lipids were markedly less unsaturated. Vegetative cells produced at 37[degree]C yielded 4.25% lipid whereas 55[degree]C cells yielded 2.8% lipid. The 37[degree]C vegetative cells contained the least unsaturated lipid. Chromatographic identification of the lipids was unsuccessful. No cephalin, sphingomyelin, or sterols were found in any of the lipids.