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Effect of Medium Composition on Glucoamylase Production During Batch Fermentation of Recombinant Saccharomyces cerevisiae
Author(s) -
Kilonzo Peter M.,
Margaritis Argyrios,
Bergougnou Maurice A.
Publication year - 2008
Publication title -
journal of the institute of brewing
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.523
H-Index - 51
eISSN - 2050-0416
pISSN - 0046-9750
DOI - 10.1002/j.2050-0416.2008.tb00311.x
Subject(s) - saccharomyces cerevisiae , fermentation , plasmid , yeast , bioreactor , recombinant dna , composition (language) , starch , chemistry , food science , strain (injury) , biochemistry , growth medium , yeast extract , chromatography , biology , bacteria , dna , gene , linguistics , philosophy , genetics , organic chemistry , anatomy
Plasmid stability of the recombinant Saccharomyces cerevisiae C468/pGAC9 (ATCC 20690) strain harboring a pGAC9 plasmid with glucoamylase genes has been investigated in shake flasks and in a bioreactor system using various compositions of media containing glucose or starch as the main carbon and energy source. The medium composition affected both the growth characteristics of S. cerevisiae and stability of the plasmid. Superior plasmid stability was obtained in yeast minimal medium and in complex medium with 0.5 to 2% D‐glucose. Plasmid stability of 92% was obtained in complex medium with 2% D‐glucose yielding 48 units of glucoamylase/g of cells compared to 54% plasmid stability achieved with 2% soluble starch, which yielded 23 units of glucoamylase/g of cells. The plasmid stability increased at high growth rates and decreased with increasing starch concentration in the complex media as compared to glucose medium. The kinetic characteristics of biomass and glucoamylase production were investigated, and a growth kinetic model was used to interpret the experimental results.