酵母の炭化水素利用に関する研究(第1報)

Abstract

Two pentose-utilizing yeasts isolated previously and other 37 standard strains of yeasts were tested for their abilities to assimilate kerosene, and it was noticed that M. japonica, one of the pentose-utilizing yeasts, could assimilate also kerosene to the extent less than that obtained in the glucose medium. Growth of the organism on hydrocarbons was raised with the increment of carbon number and hexadecane was the most suitable source of hydrocarbon within the C 8-C 16 paraffins tested. Hexadecane-oxidizing activity of the organism was noticed to be adaptive. Dialysis culture improved the assimilation of kerosene to give a higher level of growth than that of a nondialysed control performed on the concentrated medium which contained whole nutrients of the reservoir and the culturing chamber. In the reservoir of the dialysis-cultured flask, some factors were found which repressed specifically the growth on the kerosene medium but not on glucose. Hexadecane-oxidizing activity of the organism was markedly enhanced by dialysis culture, and this activity was not inhibited by an active preparation of the above-mentioned factors inhibiting kerosene assimilation. Compared with cells grown on glucose, nondialysed kerosene-grown cells exhibited a high content of crude fat in the cells and high molar ratios of histidine, arginine and valine and low ratios of aspartic acid and glycine in the acid hydrolysate of the cells, and these differences were diminished in the dialysed kerosene grown cells.