• Journal of Applied Biological Chemistry
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• v.65 no.4
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• pp.447-451
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• 2022

Phytoestrogenic S-equol production in human gut exclusively depends on the biotransformation of daidzein to dihydrodaidzein (DHD). With a growing demand for the DHD enriched biomaterials, the commercial soybean hypocotyl extract (SHE) was chosen as a substrate for the microbial DHD production by human gut bacterium MRG-1, anaerobic DHD producer. To optimize the production of DHD, anaerobic fermentation conditions, including sterilization time, growth stage of inoculum, and growth media, were investigated. Maximum DHD production (1.2 g/L) was achieved after 48 h incubation when 1% (w/v) of SHE in the 20-min-sterilized Gifu Anaeboic Medium media was inoculated with OD₆₀₀ 0.3-0.4 of MRG-1. This is the first report that crude soy biomaterial, instead of pure compounds, such as daidzin and daidzein, is utilized for the production of the DHD enriched biomaterial.

• Microbiology and Biotechnology Letters
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• v.24 no.2
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• pp.166-172
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• 1996

It is well known that actinomycetes would be useful for screening of biologically active compounds. Not only to isolate diverse actinomycete strains but to ferment those strains effectively would be important. Seven hundred and forty six strains were isolated from Cheju province, 216 strains were from Chungnam province, 158 strains were from the natural caves at Chungbuk and Kangwon provinces and 202 strains were from Chungwon area at Chungbuk province. All of these 1,322 strains were fermented on a small scale using two different media and tested for their antimicrobial activities against four bacterial strains and one yeast strain. As the result, 12.3% of those isolates were active against Staphylococcus aureus KCTC 1916, 7.6% were Staphylococcus aureus KCTC 1928, 3.9% were Escherichia coli KCTC 1924, 3.0% were Candida albicans KCTC 1940, and 2.2% were Salmonella typhimurium KCTC 1926. About 40% of those isolates showed antimicrobial activities at both two media but the others showed at either one. According to the genus of isolated strains, Streptomyces and Micromonospora showed activities with higher frequencies than others.

• Journal of Life Science
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• v.26 no.4
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• pp.446-452
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• 2016

Garlic (Allium sativum L.) and its extracts have been used in a wide range of applications, including as folk medicines in many Asian countries. This traditional herb has several functional properties and strong biological activities, making it useful as a functional food material. This study investigated the biological activities of solid-garlic after fermentation by lactic acid bacteria. Several solid-garlic fermentation strains of lactic acid bacteria were isolated from Korean traditional fermented food or obtained from the Korean Collection for Type Cultures. Lactic acid bacteria showed selective growth in garlic extracts on MRS media. Fermentation of solid garlic (heated 121℃, 15 min or not heated) by lactic acid bacteria gave total polyphenol and flavonoid contents of 731.0-845.2 g/g and 92.68-413.58 g/g, respectively. The DPPH scavenging activities and SOD like activities were measured as 7,584% and 9499%, respectively. These activities were relatively higher than a positive control, vitamin C. Measurement of antidiabetic activity using α-glucosidase inhibition assay showed that solid garlic fermented with lactic acid bacteria gave a higher activity than the control, acarbose. Fermentation of solid garlic with lactic acid bacteria may therefore help to alleviate adverse biological activities, as well as provide functional food materials.

• Microbiology and Biotechnology Letters
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• v.39 no.4
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• pp.357-363
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• 2011

This study focus was primarily the development of liquid starters for Aspergillus oryzae and Aspergillus niger prepared with wheat bran as a low cost culture medium. For the preparation of the liquid media wheat bran was added at rates of 0, 5, 10, 15 and 20% and the Aspergillus sp. strains were then inoculated to these prepared broths. The results indicated that the more that wheat bran was contained in the medium, the more mycelia was produced for A. oryzae and A. niger. The highest enzyme activities were obtained with a 10~15% adding rate of wheat bran for both strains. Changes in the enzyme activities of the liquid starters during various incubation times (0, 24, 48, 72 and 96 hrs), indicated that the highest enzyme activities were seen between 48 and 72 hrs of culture. In addition, a comparative study was carried out on the production of enzymes using wheat as a substrate in nuruk, with liquid starter made from fermented agents according to the same concentrations used with the wheat bran. The pH, acidity, amino acidity, reducing sugar content and enzyme activity (${\alpha}$-amylase, glucoamylase, acidic protease) of wheat nuruk made with liquid starter were compared with those of wheat nuruk made with solid starter. The results suggest that the liquid starter is superior in both cases.

• Korean Journal of Agricultural Science
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• v.4 no.2
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• pp.173-177
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• 1977

These experiments were conducted to investigate the formation of organic acid and ethanol during fermentation by three yeast strains. One of these was industrial strain (No.7) from Japan, and the others were wild types (No. 47, No. 239) isolated from Takju-mash and Strawbery, respectively. Conditions of fermentation were varied by differing the supply of oxygen (air), and by using different fermentation media The results obtained were as follows: 1) All the yeast strains produced higher amount of total organic acid and ethanol under the conditions which were aerobic, i.e. the flasks were opened during fermentation, than in case of using the flasks with fermentation bung. 2) Organic acid and ethanol were produced rapidly in the mash medium than in the semi-synthetic medium, i.e. total amount of organic acid and ethanol was maximized in a short time in the mash medium. 3) On the mash medium, the highest amount of organic acid was obtained by the strain No. 239, the next by No. 7 and the lowest by No. 47. Ethanol was produced on this medium with decreacing order of No. 47, No. 239, and No. 7. 4) The strain No. 239 was proved to be a powerful organic acid producer, yielding higher amount of organic acid especially under the aerobic conditions. 5) Above results suggests that the strain No. 239 could be of useful in alcoholic drink industry, due to its powerful ethanol-producing characteristic accompaning with high yielding of organic acids.

• Journal of Microbiology and Biotechnology
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• v.23 no.12
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• pp.1654-1663
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• 2013

Rice straw is closely associated with meju fermentation and it is generally known that the rice straw provides meju with many kinds of microorganisms. In order to elucidate the origin of meju fungi, the fungal diversity of rice straw was examined. Rice straw was collected from 12 Jang factories where meju are produced, and were incubated under nine different conditions by altering the media (MEA, DRBC, and DG18), and temperature ($15^{\circ}C$, $25^{\circ}C$, and $35^{\circ}C$). In total, 937 strains were isolated and identified as belonging to 39 genera and 103 species. Among these, Aspergillus, Cladosporium, Eurotium, Fusarium, and Penicillium were the dominant genera. Fusarium asiaticum (56.3%), Cladosporium cladosporioides (48.6%), Aspergillus tubingensis (37.5%), A. oryzae (31.9%), Eurotium repens (27.1%), and E. chevalieri (25.0%) were frequently isolated from the rice straw obtained from many factories. Twelve genera and 40 species of fungi that were isolated in the rice straw in this study were also isolated from meju. Specifically, A. oryzae, C. cladosporioides, E. chevalieri, E. repens, F. asiaticum, and Penicillium polonicum (11.8%), which are abundant species in meju, were also isolated frequently from rice straw. C. cladosporioides, F. asiaticum, and P. polonicum, which are abundant in the low temperature fermentation process of meju fermentation, were frequently isolated from rice straw incubated at $15^{\circ}C$ and $25^{\circ}C$, whereas A. oryzae, E. repens, and E. chevalieri, which are abundant in the high temperature fermentation process of meju fermentation, were frequently isolated from rice straw incubated at $25^{\circ}C$ and $35^{\circ}C$. This suggests that the mycobiota of rice straw has a large influence in the mycobiota of meju. The influence of fungi on the rice straw as feed and silage for livestock, and as plant pathogens for rice, are discussed as well.

• Journal of Microbiology and Biotechnology
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• v.27 no.12
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• pp.2165-2172
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• 2017

Lignocellulose is now a promising raw material for biofuel production. However, the lignin complex and crystalline cellulose require pretreatment steps for breakdown of the crystalline structure of cellulose for the generation of fermentable sugars. Moreover, several fermentation inhibitors are generated with sugar compounds, majorly furfural. The mitigation of these inhibitors is required for the further fermentation steps to proceed. Amino acids were investigated on furfural-induced growth inhibition in E. coli producing isobutanol. Glycine and serine were the most effective compounds against furfural. In minimal media, glycine conferred tolerance against furfural. From the $IC_{50}$ value for inhibitors in the production media, only glycine could alleviate growth arrest for furfural, where 6 mM glycine addition led to a slight increase in growth rate and isobutanol production from 2.6 to 2.8 g/l under furfural stress. Overexpression of glycine pathway genes did not lead to alleviation. However, addition of glycine to engineered strains blocked the growth arrest and increased the isobutanol production about 2.3-fold.

• Applied Biological Chemistry
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• v.31 no.3
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• pp.255-260
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• 1988

The optimum conditions for lactic acid fermentation by Lactobacillus acidophilus in the media containing malt syrup, skim milk or skim milk and malt syrup were studied to develope marketable fermented beverages from barley. The optimum sugar concentration of malt syrup was $10^{\circ}$ Bx. Addition of skim milk to malt syrup enhanced bacterial growth and acid formation. The best flavor of the product was obtained from the media containing 5% skim milk and sterilized at $90^{\circ}C$ for 30 minutes. Optimum temperature and pH for the formentation were $40^{\circ}C$ and 6.0, and bacterial cells grew logarithmically upto 16 hours.

• Microbiology and Biotechnology Letters
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• v.19 no.5
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• pp.491-496
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• 1991

To maximize the production of aminoglycoside-3'-phosphotransferase of E. coli ATCC 21990 carrying R factor which encodes aminoglycoside-3'-phosphotransferase (APH(3')) phosphorylating the 3'-hydroxyl group of aminoglycoside, mutants M1 and M2, media composition and several factors affecting the enzyme production during fermentation were studied. Although the specific activity of APH(3') produced by a mutant M1 was increased as much as four times than that of E. coii ATCC 21990, the growth rate was decreased. The increase of the enzyme production was obtained by increased biomass during fermentation. A mutant M2 was obtained to increase the cell growth rate. Mutant M2 cells were cultivated with optimal media and pure oxygen gas in a fed-batch mode of fermentor operation. The specific activity of APH(3') was decreased, but total enzyme activity of APH(3') was increased as much as two point five times than that of mutant MI.

• The Korean Journal of Mycology
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• v.37 no.2
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• pp.150-154
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• 2009

The diversity of microflora according to growth stage of Pleurotus ostreatus and the correlation between microbe and medium fermentation were investigated. In farmhouse I, the aerobic bacteria and fungi as longer of growing period were increased. And, thermophilic bacteria and fluorescent Pseudomonas sp. showed high density at the early stage of spawn inoculation. The thermophilic actinomycetes were distributed evenly during all the growing period, but mesophilic actinomycetes were not observed. In farmhouse II, thermophilic actinomycetes were not observed in fermented medium and density of fungi were suddenly increased at 60 days after spawn inoculation. And also, mushrooms can hardly be harvested due to Penicillium spp. After medium fermentation, density of aerobic bacteria, thermophilic bacteria, and fluorescent Pseudomonas sp. was higher at farmhouse I than those of farmhouse II. In farmhouse I, Bacillus sp. and Pseudomonas sp. dominated at early stage of mushroom growth but as time goes by, density of Bacillus sp. was higher than the others. And also, the kind of microbe showed a few at early stage of mushroom growth but increased as time goes by. In farmhouse II, Bacillus sp. was dominated at early stage of mushroom growth. And the growth of Bacillus sp. and Pseudomonas sp. showed intersect aspect each other in the farmhouse I but Bacillus sp. dominated during all growth periods in the farmhouse II.