Study on lipid fractions of Streptococcus thermophilus by TLC, GC and GC/MS techniques

In this research the lipid fraction of two strains of Streptococcus thermophilus was studied. Lipids were extracted by applying Folch method and fractioned by thin layer chromatography (TLC). Fatty acid composition was determined both before TLC, on the total fat extracted, and after TLC on diacylglycerol and apolar fractions. Gas chromatographic analysis was performed by using both flame ionization (FID) and mass spectrometer (MS) detector. The main difference between the two strains was the presence of short and medium chain fatty acids in food-born S. thermophilus. Moreover one of the most important bacterial fatty acids, C19 cyclopropane, was detected only in diacylglycerols, which, as reported in literature, are formed transiently as intermediates in the biosynthesis of glycerophospholipids.