Sterols in microorganisms

Sterols are vital components of all eukaryotic cells. This review describes the variety of sterol structures found in microalgae, yeasts, fungi, protozoans and microheterotrophs. Reports of the occurrence of sterols in prokaryotic cells are critically assessed. Methylotrophic bacteria contain unusual 4-methylsterols, but reports of 4-desmethyl sterols in cyanobacteria and other bacteria are limited and many of these seem dubious. Possible application areas for sterols derived from mass culture of microalgae and other microorganisms are highlighted.