Activities of regulatory enzymes in alkane-utilizing and lipid-accumulating yeasts and moulds.

Investigations with yeasts and moulds which accumulate up to 60 % of their dry weight as lipid, mainly triglycerides, have been primarily concerned with the quantity and quality of lipid produced by different species. The few studies on the intermediary metabolism of these micro-organisms have been confined mainly to species of Rhodotorula and Candida. Brady & Chambliss (1967) and Hofer et al. (1969) demonstrated that phosphofructokinase was absent in all the species of Rhodotorula they examined. Barbalace, Chambliss & Brady (1971) showed that pyruva tekinase from Rhodotorulaglutinis and other oxidative yeasts was not only insensitive to activation but its inhibition by ATP could not be relieved by fructose I ,6-diphosphate. The enzyme from R. gracilis, however, was activated by fructose 1,6diphosphate (Hofer, Betz & Becker, 1970). Hofer et al. (1971) later showed that the pentose phosphate pathway was the predominant mechanism for carbohydrate metabolism in those yeasts lacking phosphofructokinase. Observations with Candida 107, a lipid-accumulating, alkane-utilizing yeast, similar to Rhodotorula in possessing enzymes of the pentose pathway and lacking phosphofructokinase (Whitworth & Ratledge, 1975), led us to investigate whether the activities of regulatory enzymes of the pentose phosphate and glycolytic pathways are similar throughout lipid-accumulating or alkane-utilizing micro-organisms.