The effect of growth temperature on the fatty acid composition of fungi in the order Mucorales

The fatty acid composition of the lipids of some newly isolated thermophilic and thermotolerant fungi in the Mucorales has been compared with that of some psychrophilic and mesophilic Mucor species. For each species the fatty acid composition varied with the age of the culture and the temperature at which it was grown. The optimum growth temperatures were found to be 40°–50° for the thermophilic and thermotolerant species, 20°–25° for the mesophiles, and 10°–20°forthepsychrophiles. The lipids of the mesophilic and psychrophilic fungi examined had similar degrees of unsaturation. At 28° the degree of unsaturation of the lipids of thermotolerant species was not significantly different from those of psychrophiles and mesophiles, but thermophilic species were significantly less unsaturated. At higher temperatures the degree of unsaturation of thermotolerant and thermophilic species fell, until at 48°, they had similar degrees of unsaturation.