1. Four strains of yeast belonging to Endomycopsis and Saccharomyces species with optimum temperature of growth on hydrocarbons at 37° or more have been isolated.
2. Three more strains belonging to Saccharomyces species which tolerate a temperature of 37° for growth on hydrocarbons have also been described.
3. Growth of these strains at different temperatures and on various petroleum fractions and n-alkanes, and their crude protein content and essential amino acid profile are presented.
4. Use of these strains for production of single cell protein may obviate the necessity for elaborate cooling system for the fermentor.