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Please use this identifier to cite or link to this item: http://hdl.handle.net/10373/400

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Title: Cell physiology of baker's yeast in chemostats subjected to lactic acid perturbations
Authors: Wardrop, Forbes R.
Walker, Graeme M.
Affiliation: University of Abertay Dundee. School of Contemporary Sciences
Keywords: Baker's yeast
Lactic acid
Steady-state pertubation
Issue Date: 1999
Publisher: Food Technology and Biotechnology University of Zagreb
Type: Journal Article
Refereed: peer-reviewed
Rights: Published version (c)Food Technology and Biotechnology / University of Zagreb, available from http://www.ftb.hr/index.php/ftb/index
Citation: Wardrop, F.R. and Walker, G.M. 1999. Cell physiology of baker's yeast in chemostats subjected to lactic acid perturbations. Food Technology and Biotechnology. 37(4): pp.241-245. Available from http://www.ftb.hr/index.php/ftb/index
Abstract: Knowledge of microbial nutrition has become more relevant in recent years with the increased use of microorganisms and their products as food additives and supplements. In this paper, we describe the effect of lactic acid on the steady state growth of baker's yeast (Saccharomyces cerevisiae). This organism is frequently used by food producers as a flavour enhancer in various yeast extract preparations. Sacch. cerevisiae is propagated indu¬¨strially from sugar cane and/or beet molasses which is often of low-quality, being a zvasle product from the sugar refining process. The presence of lactic acid in batches of molasses from various sources may lead to subsequent loss of yeast biomass yield following industrial propagations. This study zvas aimed at defining the physiological effects occurring in the yeast cells subjected to perturbations, or "spikes", of lactic acid when grown in glucose-limited chemostat culture. The results of analysis of yeast biomass, cellular protein, glycogen, trehalose and RNA obtained shozved a differential response of cells to elevation of lactic acid levels zulucli zvas dependent on yeast grozuth rate. At sub-optimal growth rates the effect zvas devastating to the cells, resulting in loss in biomass, and significant changes in intermediary metabolism, possibly due to a cytotoxic effect of lactic acid diffusing into the cells. However, the yeast cells at supra-optimal grozuth rates responded with much less deviation compared to steady-state control cultures in the chemostat.
URI: http://hdl.handle.net/10373/400
ISSN: 1330-9862
Appears in Collections:Science Engineering & Technology Collection

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