Kombucha is a traditional health beverage produced by fermenting sweetened tea with a symbiotic culture of bacteria and yeasts. Consumption of kombucha beverages has been growing and there is kombucha commercially available worldwide as one of the most famous low-alcohol beverages. Kombucha beverages have been claimed to have beneficial effects on human health because they contain a variety of bioactive compounds that possess various functional properties. At present, several kinds of raw material (e.g., milk, fruit, vegetables, and herbs) have been fermented with kombucha consortium and consumed as kombucha beverages. Although several studies have been written regarding the biological activities of kombucha and raw materials, there is however little information available on the characterization of their components as well as the biological activities of fermented kombucha from many raw material mixtures. Several pharmacological activities were reviewed in the scientific literature, describing their potential implications for human health. In addition, the adverse effects and toxicity of kombucha consumption were also reviewed. In this study, we focused on the main and latest studies of the pharmacological effects of kombucha beverages produced from various kinds of raw materials, including antioxidant, anti-inflammatory, immunomodulatory, antimicrobial, anticancer, antidiabetic, antihypertensive, and antihyperlipidemic effects in in vitro and in vivo studies.

Kombucha is a functional beverage fermented by the symbiosis of bacteria and yeasts and is comprised mainly of bioactive compounds and acids that have beneficial health effects. Our research aimed to determine the optimal ratio of co-culture of the bacterium Acetobacter pasteurianus AJ605 and the yeast Zygosaccharomyces bailii YN403 for kombucha fermentation in order to improve the consistency of kombucha quality so that it can be mass produced. Microbial growth, chemical characteristics, and antioxidant activities of kombucha during fermentation were analyzed. The results showed that a co-culture ratio of 8:2 (v/v) of A. pasteurianus AJ605 and Z. bailii YN403 gave the highest antioxidant activity after 10 days of fermentation, with a DPPH IC50 value of 25.76 µl/mL and an ABTS IC50 value of 8.84 µl/mL. The co-culture ratio of 8:2 showed antioxidant activity that was not significantly different (p>0.05) from that of SCOBY (symbiotic culture of bacteria and yeasts) alone. Additionally, during fermentation, the pH of kombucha decreased to 3.16, with increases in titratable acidity and alcohol content of 7.00 g/L and 7.96 g/L, respectively. To enhance the antioxidant activity and taste quality of kombucha, black tea and roselle were mixed at various ratios and inoculated with 10% (v/v) optimal co-culture. The results showed that a high antioxidant activity was obtained using an 8:2 (w/w) ratio of black tea and roselle, at day 10 of fermentation, with a DPPH IC50 value of 23.88 µl/mL and ABTS IC50 value of 6.11 µl/mL. Moreover, the results indicate that kombucha from black tea and roselle can be a functional beverage that has high antioxidant activity and sensory acceptability.

Bacterial Cellulose (BC) production from Fermented Rice Noodle Wastewater (FRNW) was fermented by Komagataeibacter sp. PAP1. In order to increase the production of BC, the FRNW-based medium was prepared and optimized for the cultivation of this bacterium. The optimized FRNW-based medium was composed of 5 % (w/v) mannitol, 0.1 % (w/v) beef extract, 0.5 % (v/v) ethanol, 1 % (v/v) acetic acid, pH 7.0 which were incubated at 30 °C for 10 days. Under these conditions, BC yielded 11.76 ± 0.34 g/L higher (4.40 fold) than the standard Hestrin-Schramm (HS) medium. The study on growth and BC production by Komagataeibacter sp. PAP1 in optimized culture condition showed that BC production by Komagataeibacter sp. PAP1 was growth-associated. The bacterial cell of Komagataeibacter sp. PAP1 increased exponentially from the 3rd to 5th day. The BC paper sheets produced using the obtained BC pellicle from an optimized FRNW-based medium gave higher mechanical strength than those from standard HS medium. This study reveals the use of FRNW as a substrate for BC production. The results indicated that FRNW, which is more environmentally friendly, can be used as an alternative low-cost substrate for BC production.

Schizosaccharomyces pombe YM-19 and Acetobacter pasteurianus EM2-03 were isolated and identified from the traditional herbal vinegar fermentation process using cultural and molecular techniques. The two microorganisms were prepared to inoculum for an experimental herbal vinegar fermentation, which is called “Loog Plaag Mea.” The first starter culture was 10% v/v S. pombe YM1-19. Fermentation was carried out under anaerobic conditions at 30°C for 4 days. The alcohol content was 6.18±0.13% v/v and the pH value was 3.52±0.02 on day 4 of the fermentation period. Subsequently, 10% v/v A. pasteurianus EM2-03 was added to the fermentation process under aerobic conditions at 30°C for 22 days. The final herbal vinegar product contained 4.91±0.15% v/v acetic acid, and a pH value of 3.04±0.04. Its total phenolic content and IC50 value of DPPH radical scavenging were 1,908.38±38.75 µgGAE/mL and 0.017±0.001 µL/mL, respectively. The experimental fermented herbal vinegar had physicochemical properties that very similar to traditional vinegar. As a result, the isolated microorganisms can be used to improve product consistency and quality control in the mass production of vinegar.