Batch culture of Candida utilis in a medium deprived of a phosphorous source

DANLEY A. S. CAILIERI; CARLOS G. NÚÑEZ; JUAN C. DIAZ RICCI; LUIS SCIDÁ

APPLIED MICROBIOLOGY AND BIOTECHNOLOGY

SPRINGER

Lugar: Berlin; Año: 1984 vol. 19 p. 267 - 271

0175-7598

Candida utilis var. major NRRL-Y-1084 wasgrown in a defined medium without a phosphorous (P) source. During theexponential phase, cells divided according to a specific growth rate of 0.32 h-1, which is lower than the usual rate for a balanced medium (0.4-0.6 h-I). Therelative P content of the biomass decreased from 2.70% to0.75% over a period of 6 h, including 2 h of cell division arrest.At the end of this period there was another interruption of cell division. Afterthat, multiplication restarted at a considerably lower rate and it deviatedslightly from the exponential pattern.The stationary phase began when biomass P content reached0.4%-0.5%, slowly decreasing afterwards to 0.25%-0.20%. Biomasssynthesis was less affected than cell division by the relative decreaseof endogenous P, the two processes differing partially in theirkinetics. Cell lysis started shortly before the stationary phase andaffected about 20% of the population by the end of the assay. RNA and Pcontent of the resulting biomass were 2.4% and 0.25% respectively, Pbeing mainly incorporated toRNA. The relationship of biomass production to glucose uptake wasvery low, probably because the marked P deficiency called for an increase inenergy consumption for growth and specially for maintenance. Compared withyeasts grown in a balanced medium, 40% increase in glycogen was observed,whereas no mean changes in the content of cell wall carbohydrates (glucan and mannan)and that of "true protein" were found.