ABSTRACT
Single cell oils (SCO) might be defined as the edible oils obtainable from microorganisms and are similar in type and composition to those oils and fats from plants or animals. This chapter aims to provide an introductory overview to SCO and to show that the current interest in their production and use comes from a long history of interest in the exploitation of microorganisms as sources of oils and fats. Without these early endeavors, it is quite possible that none of the current commercial SCO products on the market would have been developed, since the basic understanding behind the exploitation of microbial oils would have delayed for several decades. The key events that led to the transition of microbial oils from being more or less academic curiosities 30 years ago to being important nutraceuticals included in infant formulas now were the overwhelming evidence of the dietary significance of very long chain, polyunsaturated fatty acids (PUFA) coupled with the realization that there is no adequate or safe source of them from plants or animals. What were originally unusual microorganisms have now turned out to be extraordinarily important, since these are the only realistic sources of these oils. The diversity of microorganisms is so great that it can almost be guaranteed that these current products will not be the last ones that will be launched in the 21st century as SCO.
