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Abstract: The yield and properties of cellulose produced from bacterial fermentation of black tea broth (known as Kombucha) were investigated in this study. The tea broth was fermented naturally over a period of up to 8 days in the presence of sucrose. Tea broth with a sucrose concentration of 90 g/l produced highest yield of bacterial cellulose (66.9%). The thickness and yield of bacterial cellulose increased with fermentation time. The bacterial cellulose production increased correspondingly with increased surface area:depth ratio. Changes in pH were related to the symbiotic metabolic activities of yeasts and acetic acid bacteria, and the counts of both of these in the tea broths were relatively higher than those in the cellulose layer. Findings from this study suggest that the yield of cellulose depends on many factors that need to be optimized to achieve maximum yield.
Keywords: Bacterial fermentation, Kombucha tea, bacterial cellulose
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Introduction
Kombucha is a traditionally consumed healthy beverage produced by the fermentation of sweetened black tea by a tea fungus (a symbiotic association of bacteria and yeasts) (Dufresne and Farnworth, 2000; Teoh et al., 2004; Malbasa et al., 2011). An origin of China, Kombucha is produced in a traditional manner in many households including Russia and Ukraine by fermentation using a tea fungus passed from house to house. Kombucha is a refreshing beverage that tastes like sparkling apple cider. During fermentation, the taste of Kombucha changes from a pleasantly sour lightly sparkling flavor to mild vinegar-like taste, on prolonged incubation (Sievers et al., 1995; Blanc, 1996).
Kombucha has been consumed in many countries for centuries and several health benefits have been reported (Greenwalt et al., 1998; Dufresne and Farnworth, 2000). Consumption of Kombucha has been shown to have beneficial effects on gastric, intestinal, and glandular activities and to overcome on arteriosclerosis, toxin excretion, diabetes, nervousness, and aging problems. Additionally, it can also act as a laxative and are known to relieve joint rheumatism, gout, and hemorrhoids (Reiss, 1994; Dufresne and Farnworth, 2000; Bhattacharya et al., 2011). The therapeutic benefits of consuming kombucha have been reported to range from weight loss up to curing of cancer and AIDS (Teoh et al., 2004). The free radical scavenging and antioxidant activities of Kombucha tea has been...