Experimental bioenergetics of Saccharomyces cerevisiae in respiration and fermentation
Aerobic growth of Saccharomyces cerevisiae on glucose was investigated, focusing on the heat evolution as it relates to biomass and EtOH synthesis. Aerobic fermentation and aerobic respiration were established respectively in the experimental system by performing batch and fed-batch experiments. Balanced growth batch cultivations were carried out with initial sugar concentrations of 10-70 g/L, resulting in different degrees of catabolite repression. The fermentative heat generation was continuously monitored in addition to the key culture parameters such as EtOH production rate, CO/sub 2/ evolution rate, O/sub 2/ uptake rate, sp. growth rate, and sugar consumption rate. The respective variations of the above quantities reflecting the variations in the catabolic activity of the culture were studied. This was done in order to evaluate the microbial regulatory system, the energetics of microbial growth including the rate of heat evolution, and the distribution of organic substrate between respiration and fermentation. This study was supported by closing C, energy, and electron balances on the system. The comparison of the fractions of substrate energy evolved as heat (delta h) with the fraction of available electrons transferred to O/sub 2/ (epsilon O/sub 2/) indicated equal values of the 2 (0.46) in the aerobic respiration (fed-batch cultivation). However, the glucose effect in batch cultivations resulted in smaller epsilon O/sub 2/ than delta h, while both values decreased in their absolute values. The evaluation of the heat energetic yield coefficient, together with the fraction of the available electrons transferred to O/sub 2/, contributed to the estimation of the extent of heat production through oxidative phosphorylation.
- Research Organization:
- Dept. Chem. Eng., McGill Univ. Montreal, PQ Can. H3A 2A7
- OSTI ID:
- 6779278
- Journal Information:
- Biotechnol. Bioeng.; (United States), Vol. 23:10
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
09 BIOMASS FUELS
FERMENTATION
BIOCHEMICAL REACTION KINETICS
REACTION HEAT
SACCHAROMYCES CEREVISIAE
GROWTH
RESPIRATION
AEROBIC CONDITIONS
AEROBIC DIGESTION
BATCH CULTURE
BENCH-SCALE EXPERIMENTS
BIOMASS
BIOSYNTHESIS
ETHANOL
GLUCOSE
PHOSPHORYLATION
PRODUCTION
SUBSTRATES
ALCOHOLS
ALDEHYDES
BIOCONVERSION
CARBOHYDRATES
CHEMICAL REACTIONS
DIGESTION
ENERGY SOURCES
ENTHALPY
FUNGI
HEXOSES
HYDROXY COMPOUNDS
KINETICS
MANAGEMENT
MICROORGANISMS
MONOSACCHARIDES
ORGANIC COMPOUNDS
PHYSICAL PROPERTIES
PLANTS
PROCESSING
REACTION KINETICS
RENEWABLE ENERGY SOURCES
SACCHARIDES
SACCHAROMYCES
SYNTHESIS
THERMODYNAMIC PROPERTIES
WASTE MANAGEMENT
WASTE PROCESSING
YEASTS
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