Kombucha exhibited increased antioxidant activities during fermentation. The extent of activity depended upon culture period and starter origins, which in turn determined the forms of their metabolites. Although antioxidant properties of most kombucha showed the time-dependent profiles, prolonged fermentation was not recommended because of accumulation of organic acids, which might reach harmful levels for direct consumption (Greenwalt et al., 2000). The identification of extracellular key enzymes and potent metabolites are necessary to elucidate metabolic pathway during kombucha fermentation. Metabolic manipulations may be one of the effective methods to elevate the antioxidant activities and fermentation efficiency of kombucha