Study on Soy Sauce Production from Soy Sauce-Moromi Mash by Using Bioreactor Systems

Abstract

A continuous fermentation system producing soy sauce from unsterilized soy saucemoromi mash (very viscous suspension) was investigated. The system was composed of two laboratory scale air-lift type reactors in which Zygosaccharomyces rouxii and Candida versatilis were immobilized, respectively. MI ceramics (MIC) and honeycomb ceramics (HC) treated with both acid and alkaline were good supports for immobilizing soy sauce yeasts. Efficiency of alcohol fermentation on a reactor of Z. rouxii immobilized on MIC was higher than that on HC. Unsterilized soy sauce-moromi mash was continuously fed for 35 days into the bioreactors on which were immobilized Z. rouxii and C. versatilis, respectively, and both reactors stably run without any problems. A blend of the fermentation products obtained from both reactors was heated, and evaluated good concerning flavor and taste by a sensory test.