UTILIZATION OF HYDROCARBONS AS CARBON SOURCES IN PRODUCTION OF YEAST CELLS

Abstract

For the purpose of producing yeast cells from petroleum oil, yeast which grow well on hydrocarbon-mineral salt medium were tested. Among several strains of hydrocarbon-utilizing yeast, Candida tropicalis YO-148 assimilated petroleum oil or hydrocarbons best. Cell yield was markedly increased by adjusting the culture medium to pH 7 during cultivation. Addition of a surface active agent, "Runox-M 210," also increased the cell yield. Under the best conditions, 11 g of dry yeast cells were obtained from 1 1 of culture broth initially containing 10% (v/v) of light oil after 30 hr. cultivation. Composition of hydrocarbon- and glucose-grown cells are also presented. One of the dis-tinct features of hydrocarbon-grown cells was high crude fat (7%). Crude protein and RNA contents of hydrocarbon-grown cells were 44.7% and 5.1%, respectively. Essential amino acids, except sulfur-con-taining amino acids, in hydrocarbon-grown cells were higher than those in glucose-grown cells. The nutritional value of hydrocarbon-grown cells of this strain seems to be evenly matched to that of commercially available fodder-yeast cells produced from carbohydrates.