Over the past 25 years the brewing industry has progressively employed high gravity worts due to the economic advantages it holds over the use of conventional gravity worts. However, high gravity brewing has several disadvantages which include exerting a negative effect on yeast fermentative performance. Investigations attempting to limit these detrimental effects have revealed that a range of compounds, including the addition of certain metal ions, can enhance yeast fermentation. Both magnesium and calcium are normally present in wort and play an important role in the brewing process. Magnesium bioavailability is crucial to the yeast cell due to the fundamental role this ion plays in a plethora of metabolic processes. Calcium, regarded as a non essential for cer tain yeast strains, exerts its effects mainly at the site of the plasma membrane. being involved in wort pH control and yeast fioceutation. In the present study the affects of adjusting the initial concentration of magnesium and calcium on the metabolic flux of an industrially used brewing strain of S.cerevisiae were investigated. The consequences of altering the bioavallability of these two divalent ions on yeast: sugar uptake; ethanol production; activities of key metabolic enzymes; protein composition; cell number and viability are reported.
|Journal||FASEB Journal: : The Journal of the Federation of American Societies for Experimental Biology|
|Publication status||Published - 1997|