We studied the cause of repression of fermentation in
sake moromi-mash brewed with a phytase preparation (Sigma P-9792).The pytase preparaton inhibited yeast growth.The purification of a yeast growth-inhibitory protein from the phytase preparation was carried using a variety of chromatographic techniques.The final purified protein was shown to be homogeneous by SDS-polyacylamide gel electrophoresis.The N-terminal amino acid sequence of the purified protein was found to have a high degree of homology with the glucose oxidase from
Aspergillus niger.It was confirmed that yeast growth is inhibited by purified glucose oxidase from the phytase preparation and by the
Asp. niger enzyme.The concerntration of hydrogen peroxide in the medium increased during the early stages of yeast culture with the purified glucose oxidase, then it decreased gradually. It was observed that yeast growth began when the hydrogen peroxide concentration fell.From these results, the cause of yeast growth inhibition was determined to be hydrogen peroxide formed by glucose oxidase.It was confirmed that repression of fermentation occured in
sake rnoromi-mash brewed with the purified glucose oxidase and the
Asp. niger enzyme.
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