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The response of Lactococcus lactis to reducing environmental conditions

Objectif

Lactococcus is a commercially important microorganism. It is used widely in the dairy industry. Cheese quality depends on the raw material, starter cultures and fermentation conditions (T, humidity, NaCl and pH). Redox potential has an important role in the final properties of fermented dairy products, especially their aroma. One possible explanation is the observed effect of redox potential on amino acid catabolism.

The improvement of Lactococcus for industrial purposes involves identifying and controlling the global regulatory circuits responsible for the environmental stress response. In aerobic environments, many metabolic reactions in the cell depend on the balance between oxidative and non-oxidative states which can regulate enzyme activity. Toxic radicals formed by oxygen cause cellular damage and may result in cell death or alter growth. Resistance to these negative effects includes maintaining the redox balance within the cell and the production of detoxifying enzymes.

Lactococcus lactis is known for its powerful reducing activity in milk which occurs before acidification. But little is known about what these activities are and how they are controlled. Our hypothesis is that the acidification kinetics and growth can be altered by manipulating the environmental redox potential. We will investigate this by separating the effects of oxidation stress produced by oxygen from those produced specifically by redox potential.

Environmental stress response is a complex process that can only be addressed by a genome-wide search for the individual but interlinked components. This project will combine physiology, biochemistry, molecular genetics and transcriptome analysis. It will result in new information on redox regulated genes in Lactococcus lactis. This knowledge will increase our ability to control milk and cheese fermentation processes resulting in more efficient and consistent production of high quality dairy foods with improved organoleptic properties.

Appel à propositions

FP6-2005-MOBILITY-5
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Coordinateur

INSTITUTE OF FOOD RESEARCH
Contribution de l’UE
Aucune donnée
Adresse
Norwich Research Park, Colney
N/A NORWICH
Royaume-Uni

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