Yeast Candida Lipolytica Research Articles

Cultivation of the yeast candida lipolytica on hydrocarbons. I. Degradation of n‐alkanes in batch fermentation of gas oil

AbstractThe growth of batch‐cultivated yeast Candida lipolytica on three kinds of gas oil using mineral medium was studied. A linear dependence was found between the production of yeast biomass and the consumption of n‐alkanes, while the decrease of freezing point of gas oil during cultivation had a distinct course. This disproportion was explained by different degradation of individual n‐alkanes contained in gas oil. The rate of degradation of pentadecane, hexadecane, and heptadecane was the same during the entire cultivation. On the contrary, in the first phase the utilization of shorter chain n‐alkanes, nonane to tetradecane, was more rapid while that of longer chain homologs, octadecane to pentacosane, lagged. Rapid utilization of longer chain n‐alkanes did not occur before the concentration of the other n‐alkanes decreased. Only then the rapid decrease of freezing point appeared.

LIPID COMPOSITION OF MESOPHILIC AND PSYCHROPHILIC YEASTS (CANDIDA SPECIES) AS INFLUENCED BY ENVIRONMENTAL TEMPERATURE

The lipids of three psychrophilic yeasts of the genus Candida, grown at 10°, were compared with those of a mesophilic yeast (Candida lipolytica) grown at 25° and at 10°. All the yeasts examined had similar contents of total lipids and of phosphatides, and similar phosphatide and neutral lipid compositions. However, the total fatty acids of the psychrophiles and of the mesophile grown at 10° had much higher proportions of linoleic acid and lower proportions of oleic acid than those of the mesophilic yeast grown at 25°; the psychrophilic yeasts also contained linolenic acid, not detected in the mesophilic yeast. The fatty acid composition of the psychrophilic yeast remained fairly constant during its growth cycle, but that of the mesophilic yeast at 10° showed marked changes in the proportions of oleic and linoleic acids in the early stages of growth; similar changes occurred in the mesophile grown at 25°, but at much faster rates. On the basis of these observations and others it is concluded that in the early stages of growth of the mesophile at 25° and 10°, oleic acid is converted rapidly to linoleic, which is then oxidatively metabolized during the later stages of active growth. The higher proportions of linoleic acid in the mesophile grown at 10° could be accounted for by a slower rate of metabolism of linoleic acid during the later stages of growth at the lower temperature.

LIPID COMPOSITION OF MESOPHILIC AND PSYCHROPHILIC YEASTS (CANDIDA SPECIES) AS INFLUENCED BY ENVIRONMENTAL TEMPERATURE

The lipids of three psychrophilic yeasts of the genus Candida, grown at 10°, were compared with those of a mesophilic yeast (Candida lipolytica) grown at 25° and at 10°. All the yeasts examined had similar contents of total lipids and of phosphatides, and similar phosphatide and neutral lipid compositions. However, the total fatty acids of the psychrophiles and of the mesophile grown at 10° had much higher proportions of linoleic acid and lower proportions of oleic acid than those of the mesophilic yeast grown at 25°; the psychrophilic yeasts also contained linolenic acid, not detected in the mesophilic yeast. The fatty acid composition of the psychrophilic yeast remained fairly constant during its growth cycle, but that of the mesophilic yeast at 10° showed marked changes in the proportions of oleic and linoleic acids in the early stages of growth; similar changes occurred in the mesophile grown at 25°, but at much faster rates. On the basis of these observations and others it is concluded that in the early stages of growth of the mesophile at 25° and 10°, oleic acid is converted rapidly to linoleic, which is then oxidatively metabolized during the later stages of active growth. The higher proportions of linoleic acid in the mesophile grown at 10° could be accounted for by a slower rate of metabolism of linoleic acid during the later stages of growth at the lower temperature.

Esters from Bacterial Oxidation of Olefins

Identification of esters isolated from culture fluids of bacteria growing upon terminal olefins indicates that bacteria oxidize olefins at the saturated methyl group, leaving the double bond intact. The yeast Candida lipolytica produces alpha-glycols from olefins, presumably by attacking the double bond.