A potent intracellular-lipid-producing yeast, Rhodatorula glutinis var. glutinis SW-17, was screened out from a variety of arable soils, compost heaps, and fodders, and two strains of excellent extracellular-lipid-producing yeasts, Rhodotorula glutinis var. glutinis SW-5 and Rhodotorula graminis SW-54, were screened out from the surface of many species of leaves. And then the intra- and extra-cellular Lipid productions by those Rhodotorula yeasts were studied. The results were as follows:
1. During the shaking culture of 8 days at 24℃, both the intra- and extra-cellular lipid accumulation started almost at the stationary phase of growth, when the nitrogen source in the medium was a little more than half used up. The intracellular lipid production by Rhodotorula glutinis var. glutinis SW-17 reached 58.42% (w/w) of dried yeast, and the extracellular lipid production by Rhodotorula graminis SW-54 amounted to 2.628 per liter of the medium.
2. After the carbon and nitrogen sources in the medium were almost consumed, if the yeasts were shake-cultured further in a state of starvation, the yeast cells re-utilized the already produced intro- and extra-cellular lipids and the lipids completely disappeared in the medium in about 90 days.
3. The relative concentration of carbon and nitrogen sources in the media greatly influenced both the intra- and extra-cellular lipid production. When the nitrogen source in; the medium was almost used up for the growth of yeast, and excess carbon sources. were still available, the lipid production vigorously proceeded. As long as the nitrogen source concentration in the medium was high, the lipid production was greatly suppressed.
4. The optimum pH for both the intra- and extra-cellular lipid production by those yeasts was pH 5.0-6.0.
5. The fatty acid components of the intracehular lipid of Rhodotorula glutinis var. glutinis SW-17 were myristic, palmitic, palmitoleic, stearic, oleic, linoleic, and linolenic acids. The largest components of the fatty acids were palmitic acid equivalent to 30-45% of the whole fatty acids and oleic acid equivalent to 35-50%.
6. The fatty acid components of the extracellular lipid of Rhodotorula glutinis var. glutinis SW-5 and Rhodotorula graminis SW-54 were myristic, palmitic, stearic, oleic, linoleic, linolenic, 3-D-hydroxypalmitic, and 3-D-hydroxystearic acids. The largest components of the fatty acids were 3-D-hydroxypalmitic acid equivalent to 22-25% of the acids and 3-D-hydroxystearic acid equivalent to 13-17%.
7. The polyol component of the intracellular lipids was only glycerol, whereas the polyols of extracellular lipids were glycerol, mannitol, xylitol and arabitol.
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