• KSBB Journal
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• v.9 no.4
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• pp.365-371
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• 1994

The effects of ratios of initial concentration of carbon source to the initial concentration of nitrogen source in the fermentation media on both the yields of PHB fermentation variables and the accumulation of poly-${\beta}$-hydroxybutyric acid(PHB) were investigated. The fermentation media were composed of the combination of varing glucose concentrations, 10, 20, 25, 30, 40, $50g/\ell$ and the NH4Cl concentrations 0.33, 0.4, 0.5, 1.5, 3, $5g/\ell$. The yield of biomass on glucos, Yx/s, decreased very slowly according to the increase of the ratio of C to N. And the yield became constant at 0.35(g biomass/g glucose) with the ratio higher than 70. The yield of residual biomass, Yx/s, also decreased with the ratio of C to N and finally showed a constant value of 0.065(g residual biomass/g glucose) when the ratio was higher than 65. In accordance with the augmentation of the ratio, the yield of PHB, YPHB/S, however, increased and showed the maximum value of 0.35 (g PHB/g glucose) between 40 and 60 of the ratio. The maximum yield of PHB to the change of biomass, YPHB/S, was 0.87(g PHB/g biomass), and the yie1d YPHB/RX, was 4.2(g PHB/g residual biomass). The maximum accumulation percent of PHB to the final biomass was 81% when the ratio was higher than 67.

• Journal of Hydrogen and New Energy
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• v.16 no.1
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• pp.17-24
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• 2005

We experimented on growth in light and production of hydrogen and organic matters in dark fermentation by using C. reinhardtii. In the light, growth rate of C. reinhardtii following $CO_2$ fixation was proportional to consumption rate of nitrogen source. And the starch in cell was accumulated more when the period of culture was lengthened more. But the accumulation rate of starch in cell was decreased when the growth rate of cell become dull. In the dark fermentation, the production volume and production rate of hydrogen were the highest value in the mid exponential state among other states. The utilization efficiency of substrate was better in the early exponential state than other states. In production of organic matters, acetic acid didn't change remarkably and ethanol showed the highest value in early exponential state.

• Journal of Microbiology and Biotechnology
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• v.24 no.5
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• pp.648-660
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• 2014

Doenjang, a traditional Korean fermented soybean paste, is made by mixing and ripening meju with high salt brine (approximately 18%). Meju is a naturally fermented soybean block prepared by soaking, steaming, and molding soybean. To understand living bacterial community migration and the roles of bacteria in the manufacturing process of doenjang, the diversity of culturable bacteria in meju and doenjang was examined using media supplemented with NaCl, and some physiological activities of predominant isolates were determined. Bacilli were the major bacteria involved throughout the entire manufacturing process from meju to doenjang; some of these bacteria might be present as spores during the doenjang ripening process. Bacillus siamensis was the most populous species of the genus, and Bacillus licheniformis exhibited sufficient salt tolerance to maintain its growth during doenjang ripening. Enterococcus faecalis and Enterococcus faecium, the major lactic acid bacteria (LAB) identified in this study, did not continue to grow under high NaCl conditions in doenjang. Enterococci and certain species of coagulase-negative staphylococci (CNS) were the predominant acid-producing bacteria in meju fermentation, whereas Tetragenococcus halophilus and CNS were the major acid-producing bacteria in doenjang fermentation. We conclude that bacilli, LAB, and CNS may be the major bacterial groups involved in meju fermentation and that these bacterial communities undergo a shift toward salt-tolerant bacilli, CNS, and T. halophilus during the doenjang fermentation process.

• The Korean Journal of Mycology
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• v.46 no.3
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• pp.307-314
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• 2018

The goal of this study was to investigate the microbiological characteristics of the ethanol-producing wild yeast, Aureobasidium pullulans P-1, isolated from flowers growing near the Yedang reservoir, Chungnam province, Korea, and in addition, to optimize its fermentation ability for the production of Makgeolli. A. pullulans P-1 was oval-shaped, and formed ascospores and pseudomycelium. The P-1 strain was a halophilic and sugar tolerant yeast which grew in 15% NaCl and 50% glucose-containing yeast extract-peptone-dextrose media. The P-1 strain was also resistant to 20% ethanol. Changes of the physicochemical properties during Makgeolli fermentation by A. pullulans P-1 were investigated. A maximum of 8.45% ethanol was obtained when a mixture of cooked rice, 150% water, and 35% ipguk per cooked rice was fermented by 5% A. pullulans P-1 culture broth at $25^{\circ}C$ for 10 days. Antihypertensive angiotensin I-converting enzyme inhibitory activity in the Makgeolli ferment produced by A. pullulans P-1 reached a high of 71.1% after 10 days.

• Korean Journal of Microbiology
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• v.9 no.2
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• pp.55-60
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• 1971

Among 50 yeasts of red pepper paste isolated and identified in the previous report, 12 strains of yeast which possess osmophilic and non-film characteristics were examined their growth rates and alcohol fermentation ability in red pepper medium. 5 strains of yeast possessing powerful growth rates and excellent alcohol fermentation ability were selected as excellent yeasts in this experiment. And their cultural conditions, salt resistance and red pepper concentration upon the growth were examined in this report. The results obtained were as follows ; 1) Among 12 strains of yeast, Saccharomyces cerevisiae group II(strain $D_1$), Saccharomyces oviformis($D_2$), Saccharomyces steineri($M_3$), Saccharomyces rouxii($D_9$) and Saccharomyces mellis($G_8$) were selected as excellent yeasts. 2) Among 5 strains of yeast selected, the strain $D_1$ and $D_2$showed the best alcohol fermentation ability and the best fermentative flavour. 3) The optimum temperature for growth of the strain $D_1$ and $D_2$ was $25^{\circ}C$$M_3$, $D_9$ and $G_8$ $30^{\circ}C$$D_1$ and $D_2$ was $62^{\circ}C$$M_3$,$D_9$ and $G_8$ ws 60.deg.C with treatment for 10 minutes. 4) The optimum pH for growth of all strains was around 5.0. 5) The strain $D_1$ and $M_3$were grown exceedingly well on the emdia containing 3 percent of NaCl and $D_2$,$D_9$ and $G_8$ on the media containing 6 percent of NaCl. 6) In the case of 5 percent of red pepper liquor added 5 percent of glucose was more nutritional than in the case of 5 percent glucose only. However, the growth rates of yeasts were restrained by the increase of red pepper concentration.

• Microbiology and Biotechnology Letters
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• v.51 no.2
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• pp.147-156
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• 2023

Tetragenococcus halophilus CY54, an isolate from jeotgal, grows best in media with 5% NaCl and can grow at 18% and higher salt concentration. Three different doenjang samples were prepared with multiple starters including T. halophilus CY54. TBZA doenjang was prepared with T. halophilus, Bacillus subtilis, Zygosaccharomyces rouxii and Aspergillus oryzae. BZA doenjang was prepared with the same 3 starters except T. halophilus. KACC doenjang was prepared with a single starter, B. subtilis KACC16750. During 16 weeks of fermentation at 25℃, the viable counts were maintained in the range of 7-8 log CFU/g in all 3 samples. As fermentation progressed, pH decreased and titratable acidity (TA) gradually increased. Crude protein contents decreased slightly. TBZA doenjang showed higher amino-type nitrogen (ANN) and volatile basic nitrogen (VBN) contents, and KACC doenjang showed higher ammonia-type nitrogen (AMN) content. TBZA doenjang showed higher fibrinolytic and protease activity than other doenjang samples. Metabolites analyses by GC/MS showed that doenjang samples were separated from each other by partial least squares-discriminant analysis (PLS-DA) analysis. Seventeen major metabolites involved in the differences between samples were identified and they included organic acids, amino acids, sugars, fatty acids and alcohols. TBZA doenjang showed higher contents for most metabolites responsible for flavor and taste of fermented foods including doenjang. These results showed that T. halophilus could be useful as a starter for doenjang and can improve the product quality by accelerating the fermentation processes.

• Applied Biological Chemistry
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• v.13 no.3
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• pp.187-191
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• 1970

This experiment was carried out to isolate osmophilic yeasts for higher concentration of NaCl than 20 per cent may affect greatly the fermentation of soy sauce. 6 strains of yeasts were selected from the soy sauce mashes at the fermentating periods and identified observing their morphological characteristics. Their salt-resistance and effects upon the flavor of soy sauce were examined. The results obtained were as follows: (1) The strain $T_3,T_5,$ and $T_{11},\;T_8,\;T_9,\;and\; T_{10},$ selected were identified Saccharomyces cerevisiae group II, Debaryomyces nicotianae, Saccharomyces chevalieri, Saccharomyces rouxii and Saccharomyces rosei, respectively. (2) They were more salt-resistant on the liquid media than on the solid media in the case of cultures on the media containing more than 26 per cent of NaCl. (3) They were grown on the media containing 5-23 per cent of NaCl better than containing none of NaCl. (4) The strain $T_3,\;T_8,\;T_9,\;and\; T_{10}$ were grown on the media containing up to 28 per cent of NaCl, and $T_5\;and\;T_{11}$ up to 32 per cent of NaCl is the case of liquid cultures. (5) Among them, the strain $T_9$ showed the best alcohol fermentation ability and the best fermentative flavor, and $T_5\;and\;T_{11}$ formed moldy smell and pellicle.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1986.12a
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• pp.522.2-522
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• 1986

In order to optimally induce sporulation and toxin formation in Bacillus thuringiensis, exhaustion of specific nutrients as well as resuspension experiments were tried. Sporulation and toxin formation was most abunduntly occurred when the growth was limited by carbon source. It was also occurred in a resuspension medium containing only distilled water. Various environmental and physiological factors affecting the efficiencies of spore and toxin formation were examined in chemically defined media. As a result of these studies, a batch fermentation resulted in higher spore and toxin yield than ever reported

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.09a
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• pp.107-110
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• 2001

The biological control potential of entomopathogenic nematodes (EPN) can be enhanced by improved culture efficiency. Optimization of media is a key factor for improving in vitro mass production of entomopathogenic nematodes. EPN yield was dependant of complex medium concentration, of which mixture is carbohydrates, lipids, proteins, salts, and growth factors, on the growth of Heterorhabditis bacteriophora and its symbiotic bacterium Photorhabdus luminescensLipids.

• Journal of Hydrogen and New Energy
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• v.21 no.1
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• pp.12-18
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• 2010

Photobiological hydrogen production using Rhodobacter sphaeroides KD131 was studied on the effect of light intensities and nitrogen sources. Media containing malate and glutamate were shown higher hydrogen production rate than that containing succinate and $(NH_4)_2SO_4$ at the $110\;W/m^2$ illumination by halogen lamp at $30^{\circ}C$. Media lacking glutamate as the nitrogen source exhibited higher hydrogen production than that containing glutamate. Initial cell concentration was optimized to 1.0 at the absorbance of 660 nm. Hydrogen production was increased by increasing the light intensity from 0 to $216\;W/m^2$ but the increasing rate declined over $108\;W/m^2$.