• Preventive Nutrition and Food Science
• /
• 제5권3호
• /
• pp.165-169
• /
• 2000

Kombucha beverages were made from sweetened tea by Oriental, European and Tibetan tea fungus starters. The hot water extracts o green tea, black tea, Gugija and Omija were mixed with white and/or brown sugar, and were fermented under a static culture at 3$0^{\circ}C$. Titrable acidity, pH, color and cellulose production in kombucha beverages were evaluated. All tea fungus starters showed a higher acid production in green/black tea extracts rather than Gugija and Omija extracts. In green/black tea extracts Oriental tea fungus produced a kombucha beverage with a higher titrable acidity and lower pH than those of European and Tibetan tea fungus starters. By the static fermentation of green/black tea extract for 18 days, Oriental, Tibetan and European tea fungus starters produced cellulose pellicles of 0.43g, 0.16g, and 0.19 g (dry weight) on the top in the culture, respectively. As a mother starter, the cellulose pellicle was more efficient in acid production compared with tea fungus broth. Oriental/Tibetan mixed tea fungus showed the best acid production in the green/black tea extract supplemented with brown sugar.

• 한국식품영양과학회지
• /
• 제36권10호
• /
• pp.1341-1350
• /
• 2007

본 연구에서는 국내산 감귤과즙을 이용하여 고기능성 세균 셀룰로오스를 대량생산하기 위해 감귤과즙으로부터 감귤 내성의 Gluconacetobacter hansenii TL-2C를 선별한 후 pilot 시설을 이용하여 감귤겔을 대량 생산할 수 있는 방법을 개발하였다. 유기산의 약 80%가 citric acid로 내성균의 분리가 부득이한 것으로 판정되어, 겔 발효균의 모체인 tea fungus에서 G. hanenii TF-2를 분리, 여기에 UV를 조사하여 TL-2를 분리한 후, 감귤배지에서 반복배양하여 citrate내성균인 G. hansenii TL-2C를 분리하였다. 감귤농축액 100배 희석액에 initial sucrose 함량 10%(w/v), ethanol 1%(v/v) 을 첨가한 배양액에 종균을 5%(w/v)접종하였다. 대형 4각의 FRP 용기에 뚜껑을 덮고 과즙의 높이를 26 mm로 충진하였으며, $30^{\circ}C$ 배양실에서 14일간 정치배양한 후 세로 360 mm,가로 650 mm, 두께 25 mm 이상의 대형 겔을 지속적으로 생산할 수 있었다.

• Journal of Microbiology and Biotechnology
• /
• 제21권7호
• /
• pp.739-745
• /
• 2011

During the production of grape wine, the formation of thick leathery pellicle/bacterial cellulose (BC) at the airliquid interface was due to the bacterium, which was isolated and identified as Gluconacetobacter hansenii UAC09. Cultural conditions for bacterial cellulose production from G. hansenii UAC09 were optimized by central composite rotatable experimental design. To economize the BC production, coffee cherry husk (CCH) extract and corn steep liquor (CSL) were used as less expensive sources of carbon and nitrogen, respectively. CCH and CSL are byproducts from the coffee processing and starch processing industry, respectively. The interactions between pH (4.5-8.5), CSL (2-10%), alcohol (0.5-2%), acetic acid (0.5-2%), and water dilution rate to CCH ratio (1:1 to 1:5) were studied using response surface methodology. The optimum conditions for maximum BC production were pH (6.64), CSL (10%), alcohol (0.5%), acetic acid (1.13%), and water to CCH ratio (1:1). After 2 weeks of fermentation, the amount of BC produced was 6.24 g/l. This yield was comparable to the predicted value of 6.09 g/l. This is the first report on the optimization of the fermentation medium by RSM using CCH extract as the carbon source for BC production by G. hansenii UAC09.

• 한국식품과학회지
• /
• 제35권6호
• /
• pp.1150-1154
• /
• 2003

식초공장에서 Acetobacter pasteruianus로 정치배양중인 식초 생산과정과 숙성중인 현미식초를 오염시켜 균막을 형성한 것으로부터 균을 분리하여 식초를 오염시키는 균의 특성을 밝히고자 하였다. 공장에서 식초제품을 생산하거나 가정에서 식초제품을 사용할 경우에 오염을 일으키는 초산균의 생육에 관하여 배양조건 및 생육억제 방법을 검토하였다. 초산균에 오염되어 균막이 형성된 식초로부터 초산균을 분리하여 형태학적, 배양적 및 생리학적 특성을 검토한 결과 Acetobacter속에 포함됨을 알 수 있었다. 그리고 정치배양 기간 동안에 셀룰로오스 생산량을 확인하고자 14일간 배양한 결과 두꺼운 셀룰로오스를 생성하여 Acetobacter xylinum으로 판단되었으며 7%이상의 초산농도와 10%의 에탄올농도, 1.5%의 NaCl농도, $10^{\circ}C$ 이하와 $40^{\circ}C$ 이상의 온도에서 생육할 수 없었다.

• Mycobiology
• /
• 제47권2호
• /
• pp.250-255
• /
• 2019

In the present study, we aimed to determine the cause of surface film formation in three rice vinegars fermented using the traditional static fermentation method. The pH and total acidity of vinegar were 3.0-3.3 and 3.0-8.7%, respectively, and acetic acid was the predominant organic acid present. Colonies showing a clear halo on GYC medium were isolated from the surface film of all vinegars. Via 16S rDNA sequencing, all of the isolates were identified as Acetobacter pasteurianus. Furthermore, field-emission scanning electron microscopy analysis showed that the bacterial cells had a rough surface, were rod-shaped, and were ${\sim}1{\times}2{\mu}m$ in size. Interestingly, cells of the isolate from one of the vinegars were surrounded with an extremely fine threadlike structure. Thus, our results suggest that formation of the surface film in rice vinegar was attributable not to external contamination, to the production of bacterial cellulose by A. pasteurianus to withstand the high concentrations of acetic acid generated during fermentation. However, because of the formation of a surface film in vinegar is undesirable from an industrial perspective, further studies should focus on devising a modified fermentation process to prevent surface film formation and consequent quality degradation.

• Journal of Microbiology and Biotechnology
• /
• 제14권2호
• /
• pp.276-283
• /
• 2004

Screening was performed to isolate cellulose-producing microorganisms from the Korean traditional fermented persimmon vinegar. The resulting strain, KJ $145^{T}$, was then taxonomically investigated by phenotypic characterization, particularly chemotaxonomic, and by phylogenetic inference based on a 16S rDNA sequence analysis including other related taxa. Strain KJ $145^{T}$ was found to grow rapidly and form pale white colonies with smooth to rough surfaces on a GYC agar. Strain KJ $145^T$ also produced acetate from ethanol, and was tolerable to 10% ethanol in SM medium. In a static culture, a thick cellulose pellicle was produced, and in GYC broth, the strain grew at temperatures ranging from 28 to $40^\circ{C}$ with an optimum pH of 4.0. The genomic DNA G+C content of strain KJ $145^T$ was 61.9 mol%, and the predominant ubiquinone was Q 10 as the major quinone and Q9 as the minor quinone. The major cellular fatty acids were $C_{16:0}$ and the sum in feature 7 ($C_{18:1}$ w9c, w12t and/or w7c). A 16S rRNA-targeted oligonucleotide probe specific for strain KJ $145^T$was constructed, and the phylogenetic position of the new species was derived from a 16S rDNA-based tree. When comparing the 16S rDNA nucleotide sequences, strain KJ $145^T$ was found to be most closely related to G. hansenii LMG $1527^T$ (99.2%), although KJ $145^T$ was still distinct from G. hansenii LMG $l527^T$ and G. xylinus LMG $1515^T$ in certain phenotypic characteristics. Therefore, on the basis of 16S rDNA sequences and taxonomic characteristics, it is proposed that strain KJ $145^T$ should be placed in the genus Gluconacetobacter as a new species, Gluconacetobacter persimmonis sp. nov., under the type-strain KJ $145^T$ (=KCTC =$10175BP^T$=KCCM=$10354^T$).