The pH Range for the Growth of Sacch. rouxii and Its Utility for Miso Brewing

Abstract

The pH range for the growth of Sacch. rouxii in the environment of a high concentration of sodium chloride was studied and its utility for Miso brewing was also shown in respect to the pH dependence.1. The strains of Sacch. rouxii were classified into three groups on the basis of their pH dependence in the saline medium at 25°C.Group-A: Growth was almost equal in the range of pH3.5-6.5 in the media of 0-3M of NaCl.Group-B: Normal growth was limited in the range of pH 3.5-6.0, 3.5-5.5 in the media of 2M, 3M of NaCl, respectively.Group-C: Normal growth was limited in the range of pH 4.0-5.0 in the media of 3M of NaCl.In general, the range of growth pH was reduced at higher concentrations of sodium chloride and at higher temperature. This tendency was most remarkable in the Group-C.2. In the distribution study, it was revealed that Group-A was most abundant in salty-redMiso of excellent quality and Group-C was the commonest in Soy-mashes.3. By means of plating on three different pH (4.8, 5.5 and 6.0) media containing casamino acid, yeast extract and 18% sodium chloride with McIlvaine's buffer solution, group enumeration was successfully distinguished.4. From the results of brewing trials, Group-A was considered to be the most effective yeast for Miso fermentation.