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Advisor(s)
Abstract(s)
The importance of controlling the expression of heterologous cutinase in a recombinant Saccharomyces cerevisiae SU50 strain was investigated. Maximum specific growth rate and the biomass yield increased 1.91 and 1.16 fold, respectively, when cutinase production was induced by galactose in a pre-fermentation step. However, only 19% of specific cell activity was obtained in comparison to other fermentations following a pre-fermentation step without induction of cutinase expression. Thus, the pre-fermentation step was performed using a selective medium not containing galactose, and the fermentation was performed with a cheaper and complex non-selective medium containing galactose. Under these conditions, and with the aim of maximising the specific cutinase activity, a pre-fermentation with low volume and high density of viable cells must be used. However, due to the low pre-fermentation volume, low yeast cell concentrations and low specific cell activities were obtained after 96 h of fermentation. Otherwise, when the aim was to maximise cutinase yield and productivity, a pre-fermentation volume of 10% (v/v) in relation to fermentation and in the exponential growth phase with a cell concentration between 1.1 and 1.8 g dcw/l should be used. A higher pre-fermentation volume, such as 20% (v/v), would still be economical in the case of a pre-fermentation with low cell density or low cell viability.
Description
Keywords
Cutinase Fusarium solani pisi Inoculum Pre-fermentation Saccharomyces cerevisiae
Citation
CALADO, Cecília R. C.; [et al] – Effect of pre-fermentation on the production of cutinase by a recombinant Saccharomyces cerevisiae. Journal of Bioscience and Bioengineering. ISSN 1389-1723. Vol. 93, N.º 4 (2002), pp. 354-359
Publisher
Elsevier