In order to obtain basic information on the production of single cell protein from petroleum, more than 400 yeast strains were isolated from various soil samples in Korea utilizing petroleum hydrocarbon as the sole carbon source.
A yeast strain showing the highest cell yield among the isolated strains was selected and identified. The optimal culture condition was searched in the flasks shaken throughout the procedure. And the growing characteristics for the selected yeast strain and chemical analysis of the yeast cell component were carried out.
The results obtained were as follows:
1. The selected yeast strain was identified as Candida curvata and we named it Candia curvata-SNU 70.
2. The composition of the medium proposed for the present yeast strain is: Light Gas Oil 30㎖, Urea 400㎎, Ammonium sulfate 100㎎, Potasium phosphate (monobasic) 670㎎, Sodium phosphate (dibasic) 330㎎, Magnesium sulfate 500㎎, Calcium carbonate 3g, Yeast extract 50㎎, Tween 20 0.05㎖, Tap water 1,000㎖.
3. Other culture conditions employed for the yeast were pH 5.5-7.0, temp. 30℃ under an affluent aerobic state.
4. Addition of light gas oil in portions to the culture media as the growth proceeded was more effective, especially in the cultivation on the higher oil concentration media.
5. Studies on the propagation of the yeast cells in the light gas oil medium revealed that the yeast has the lag phase lasted 16 hours and the logarithmic growth phase covered 16 to 28 hours. The specific growth rate was about 0.22 hr^(-1) and doubling time was 3.2 hrs. during the logarithmic growth phase.
6. Under the cultural condition employed, the cell yield against the amount of light gas oil (wt%) was 16.1% and the protein content of the dried yeast cells was 48.4%.
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