Abstract The efficiency of yeasts isolated from decaying fruits was investigated. The strains studied were Torulopsis westerdijkii, Paratorulopsis ingeniosa, P. maris, Geotrichum novakii , and four different strains of G. candidum. G. candidum was the most promising new protein producing strain. The effects of molasses, corn steep liquor, and different carbon and nitrogen sources on yeast and protein production by G. candidum have been studied. A newly formulated synthetic medium supporting growth and protein yield of G. candidum has been adopted.