Fatty acid oxidation by Penicillium roqueforti.

Although the oxidation of fatty acids by molds has received only superficial study, it has been found that Penicillium roqueforti forms methyl ketones as products of the oxidation. The distinctive taste and odor of bleu cheese is suggestive of 2-heptanone (Hammer and Bryant, 1937), and this compound, together with other methyl ketones, has been isolated from a ripe cheese and identified (Patton, 1950). Experimental work on fatty-acid oxidation by ketone-forming molds has been limited to growing cultures from which methyl ketones were isolated after a period of incubation (Starkle, 1924; Stokoe, 1928; Hammer and Bryant, 1937). These experimenters found that the molds produced methyl ketones of one less carbon atom than the fatty acids supplied; however, the results were complicated by the many reactions of growing cultures. The present study was limited, therefore, to relatively short experiments with resting cells and a single substrate in order to eliminate synthetic reactions.