Brewing performance of a genetically transformed yeast with acetolactate decarboxylase activity.

Shimizu, F., Sone, H. and Inoue, T.

Abstract
A recombinant brewers' yeast producing exogenous acetolactic decarboxylase (ALDC) has been studied to determine its effect on the reduction of total diacetyl (DA) produced during wort fermentation, in particular under conditions known to produce high levels of total DA. The rate of total DA reduction under all malt wort, high temperature conditions have been almost identical to the rate of reduction under normal fermentation conditions. Immobilised ALDC producing yeast has reduced total DA, even though ALDC activity has decreased gradually. No significant difference has been found in the characteristics of the ALDC producing yeast and the parent yeast. ALDC of recombinant yeast has been found to be located in the cytoplasm.
Keywords : brewing carboxylic acid fermentation genetics recombination yeast