Martins L O, Jurado A S, Madeira V M
Centro de Biologia Celular, Universidade de Coimbra, Portugal.
Biochim Biophys Acta. 1990 Jun 28;1045(1):17-20. doi: 10.1016/0005-2760(90)90198-7.
Bacillus stearothermophilus was grown within the temperature range of 48 to 68 degrees C in a complex medium and in the range of 45 to 72 degrees C in the presence of 2.5 mM Ca2+. The main fatty acids of lipid extracts contain 15 to 17 carbon atoms, mostly branched-chain species. The most prevalent saturated straight-chain fatty acid is n-C16. The total amount of branched-chain species decreases with increasing temperature of growth from 48 to 68 degrees C, whereas the straight-chain species increase. Thus, n-C16 almost doubles while i-C16, i-C17 and a-C17 decrease by 41.2, 28.9 and 41.9%, respectively. In the presence of Ca2+, the lipid metabolism favours the biosynthesis of straight-chain fatty acids with depression of branched-chain species, especially at lower temperatures. At high temperatures, Ca2+ has a less pronounced effect in the lipid biosynthesis. However, above 68 degrees C, a significant decrease is observed among the branched-chain fatty acids i-C15, i-C17 and a-C17 with a consequent increase in n-C16. Furthermore, a remarkable increase is observed in oleic acid (from 2.7% at 68 degrees C to 11.5% at the extreme 72 degrees C.
