Production of soy-sauce by use of yeast cultured in a medium including wastewater produced by desalted soy-sauce lees

Desalting is operated to recycle soy-sauce lees produced in factories. Wastewater with especially high COD value produced in the operation needs to be suitably treated. The wastewater was added instead of raw soy-sauce to a medium for the soy-sauce yeast Zygosaccharomyces rouxii ZR 510 strain, because the composition of the wastewater was similar to that of a common soy-sauce. There was no significant difference in the concentration of the cultured yeast between in the media prepared by the addition of the wastewater and the raw soy-sauce. Both the media with the cultured yeast are added in soy-sauce mash separately. No difference was found in alcohol fermentation of the yeast in the mash between the media. Main constituents and sensory evaluation of final products were also comparable between the media. Those facts showed that a soy-sauce product similar to a common soy-sauce product in quality could be brewed using the wastewater, One of the effective methods to use a liquid waste including a large amount of organic matters was introduced in this study.