Substrate inhibition kinetics of Saccharomyces cerevisiae in fed-batch cultures operated at constant glucose and maltose concentration levels

Abstract

Fed-batch culture is the mode of operation of choice in industrial baker's yeast fermentation. The particular mode of culture, operated at stable glucose and maltose concentration levels, was employed in this work in order to estimate important kinetic parameters in a process mostly described in the literature as batch or continuous culture. This way, the effects of a continuously falling sugar level during a batch process were avoided and therefore the effects of various (stable) sugar levels on growth kinetics were evaluated. Comparing the kinetics of growth and the inhibition by the substrate in cultures grown on glucose, which is the preferential sugar source for Saccharomyces cerevisiae, and maltose, the most common sugar source in industrial media for baker's yeast production, a milder inhibition effect by the substrate in maltose-grown cells was observed, as well as a higher yield coefficient. The observed sugar inhibition effect in glucostat cultures was taken into account in modeling substrate inhibition kinetics. The inhibition coefficient Ki increased with increasing sugar concentration levels, but it appeared to be unaffected by the type of substrate and almost equal for both substrates at elevated concentration levels.

Fermentation studies on roselle (Hibiscus sabdariffa) calyx neutralized with trona (sodium sesquicarbonate) at different concentrations

“…The ability of the Aspergillus group to grow as nondestructive organisms over a normal range of storage temperature and to grow at low water activity (a w ) enhance its growth and isolation. Saccharomyces cerevisiae has the ability of utilizing a wider range of substances such as molasses, potatoes, citrus, banana, vegetables (Papagianni et al 2007). It possesses a known ability for assimilating carbohydrate present in starchy waste.…”

Lipid production by Rhodosporidium toruloides Y4 using different substrate feeding strategies

“…These results suggested that substrate concentration had a major eVect on DCW and lipid production. A lower substrate concentration was favorable for DCW and lipid production using the fed-batch process, because higher glucose concentration may exhibit inhibitory eVects on cell growth and regulatory eVects on cellular metabolism [1,9,14]. Similarly, lower residual glucose concentration was also found beneWcial for the production of polyhydroxybutyrate with a fed-batch process [22].…”

Dimensionless parameters to summarize the influence of microbial growth and inhibition on the bioremediation of groundwater contaminants

“…Andrews ' (1968) equation (4) is the most commonly used form of growth kinetic model that includes inhibition (e.g. Jackson and Edwards 1972;Shen and Wang 1994;Sheintuch et al 1995;Chen and Hao 1996;Surmacz-Gorska et al 1996;López-Fiuza et al 2002;Carrera et al 2004;Papagianni et al 2007). The mass balance equation for growth and decay of the microbial population can be written as:…”