The influence of conditions of growth on the endogenous metabolism ofSaccharomyces cerevisiae: Effect on respiratory activity

Abstract

The relationship between conditions of growth and the effect of long-term starvation under aerobic conditions on the endogenous and exogenous respiratory activity ofSaccharomyces cerevisiae was studied. Cells were grown in batch culture at 30 C under aerobic conditions on a galactose or glucose carbon source and under anaerobic conditions on glucose. The washed cells were starved under aerobic conditions for periods of up to 72 hours.The endogenous respiratory quotient (RQ) of the galactose-grown cells was 0.83 during the 72 hours' starvation period, whereas the cells grown under aerobic conditions on glucose had an initial RQ of 0.91 which decreased to to 0.86. After more than 24 hours' starvation both types of aerobically grown cells had a constant endogenous Q~j~ value of 1.0 1.4 #1~rag dry weight/hour. Exogenous glucose and galactose was respired by the cells in a characteristic manner determined by their respective growth conditions. The major factor determining the viability of aerobically grown cells during starvation appeared to be the amount of endogenous reserves. The greater loss of viability of the anaerobically grown cells during starvation was not caused by a loss of respiratory activity but rather a rapid depletion of endogenous reserves probably as a consequence of their lack of functional mitochondria and need for NADPH to synthesise structural lipids necessitating greater dependence on glycolysis as a means of energy production.

Control of phenol biodegradation by using CO2evolution rate as an activity indicator

“…In addition, cell respiration declined very rapidly and was very low after 24 h. Long-term starvation (72 h) on yeast produced a diminution of 75% on the viability of cells (21). Similar results were presented by Arbuckle and Kennedy (22) who found that activated sludge acclimated to degrade phenolic compounds lost its ability when these compounds were absent for several days.…”

The effect of inoculum preparation on the fully aerated growth of Saccharomyces cerevisiae with a glucose substrate.

“…Most experiments reporting respiratory adaptation describe short term changes (<24 hr) in organisms subjected to a shift from an anaerobic to aerobic environment (1-4, 7, 17,18). However, studies of adaptation of yeast over longer time intervals have also been reported (7,10,14,19).…”

Stability of the Plasma Membrane in Saccharomyces rouxii and Its Relationship to Glucose Tolerance

“…The production of D-arabitol served as a fermentation product which allowed the regeneration of oxidized nicotinamide adenine dinucleotide phosphate as well as a solute compatible with enzyme function (4). This pathway would ensure a large supply of reduced nicotinamide adenine dinucleotide phosphate which could be used for lipid synthesis and modification of the plasma membrane (19). Modifications in the chemical composition of the plasma membrane may help account for the results reported in this study.…”