Nutritive Value of Lipid in Hydrocarbon Yeast

Abstract

Lipid in 4 kinds of hydrocarbon yeast, A, B, C and D, grown on n-paraffin in this country, was extracted by 3 procedures and its gross and available energy by growing chicks and presence of toxicity in it was studied.Yeast was refluxed with 3 time (w/v) of methanol for one hour, then crude lipid was obtained by adding double volume of chloroform to the methanol solution. Availability of the crude lipid was determined by bioassay procedure reported as mini-test5). The crude lipide was further purified as described by Folch et al.6) to get pure lipid, which was fractionated into 2, acetone soluble and insoluble fractions.Pure lipid was also obtained in HCl-treated yeast. Extract and residue were obtained by extracting yeast by 4 to 6 times of acetone, chloroform, ethyl acetate and ethanol in this order. These samples were fed to one-week-old chicks for 2 days. The chicks were then fed the same amount of the chick starter diet for 12 days.The availability of crude lipid in hydrocarbon yeast by growing chicks was excellent, though the caloric value of the lipid was 8.0-8.5kcal/g. Pure lipid in yeast A, B and C contained only about 28% of acetone soluble simple lipid, while that in yeast D contained 56% of simple lipid, the difference being highly significant statistically.Since caloric value of pure or simple lipid obtained without HCl-treatment was lower than that of pure lipid obtained after HCl-treatment, the HCl-treatment, originally attempted to destroy the cell wall of yeast, was suspected to have severe influence on the composition and the nature of lipid in yeast.No data were obtained indicating the acute toxic substance in the yeasts tested.