• Nutrition Research and Practice
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• v.1 no.4
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• pp.260-265
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• 2007

Preservation methods on the physiological and brewing technical characters in bottom and top brewing yeast strains were investigated. The preserved yeasts were reactivated after 24 months storage and grown up to stationary phase. The samples of filter paper storage indicated a higher cell growth and viability during propagation than those of nitrogen and lyophilization storage independent on propagation temperature. In addition, the filter paper storage demonstrated a faster absorption of free amino nitrogen and a highest level of higher aliphatic alcohols production during propagation than other preservation methods, which can be attributed to intensive cell growth during propagation. Moreover, the filter paper storage showed a faster accumulation for glycogen and trehalose during propagation, whereas, in particular, lyophilization storage noted a longer adaptation time regarding synthesis of glycogen and trehalose with delayed cell growth. In beer analysis, the filter paper storage formed an increased higher aliphatic alcohols than control. In conclusion, the preservation of filter paper affected positively on yeast growth, viability and beer quality independent on propagation temperature. In addition, in this study, it was obtained that the HICF and Helm-test can be involved as rapid methods for determination of flocculation capacity.

• Microbiology and Biotechnology Letters
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• v.22 no.1
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• pp.85-91
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• 1994

The characteristcs of monascus fermentation using a hyperpigment-producing mutant, Monascus sp. J101, were analyzed, and the extractive fermentations employing permeabilizing agents and resin were carried out to increase the productivity of red pigment. And the kinetic analysis was also carried out in case of the monascus fermentation using Amberlite XAD-7. The extracellular content of the red pigment produced by Monascus sp. J101 was about 17% of the total, and the production of pigment was regulated by its own product. The cell growth reached a stationary phase at 48 hours ofter inoculation, whereas the pigment production continued up to 100 hours, which showed the pattern of a mixed growth-associated type. During the fermentation, various permeabilizing agents were added to the culture medium and their effects on pigment production were examined. By adding 0.05% Triton X-100 at 48 hours of cultivation, about an 18% increase in pigment production was accomplished as compared to the control, 12% ethyle acetate and 15% for 0.05% deoxycholate, respectively. When a nonionic adsorbent, Amberlite XAD-7 was added to the culture medium at a concentration of 12.0% at 48 hours of cultivation, the pigment production was enhanced by about 48.9% as compared to the control.

• Journal of Microbiology and Biotechnology
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• v.21 no.5
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• pp.515-518
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• 2011

A gene encoding bacillopeptidase F, bpr86-1, was cloned from B. amyloliquefaciens CH86-1 isolated from cheonggukjang. This gene could encode a preproenzyme of 1,431 amino acids. When bpr86-1 was introduced into B. subtilis WB600 via pHY300PLK, an E. coli-Bacillus shuttle vector, the transformant showed fibrinolytic activity. During growth on LB, the fibrinolytic activity of cells increased sharply when they entered the stationary phase. The highest activity (761.4 mU/mg protein) was observed at 96 h of cultivation.

• Applied Biological Chemistry
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• v.27 no.1
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• pp.45-51
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• 1984

Kluyveromyces marxinus LG contains an inulase activity which is inducible by growth on inulin. The highest enzyme activity obtained at the initial stage of stationary phase of growth curve. The partially purified inulase hydrolyzed inulin, sucrose and raffinose. This enzyme showed the maximal activity at pH 4.0 and temperature of $55^{\circ}C$ for inulin and sucrose. It was also markedly inhibited by $Hg^{++}\;and\;Ag^{+}$ but not EDTA. This inulase was charaterized as a undo type which contains invertase activity and Km values for inulin and sucrose were $1.2{\times}10^{-2}M\;and\;1.3{\times}10^{-4}M$, respectively.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.159-162
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• 2000

It has been commonly known that cell growth is inhibited by the lack of dissolved oxygen and mass transfer inhibition of nutrients at stationary phase in fed-batch culture. In this study, Pluronic F-68 and oxygen vectors were added in Angelica gigas Nakai suspension culture in order to enhance cell growth in fed-batch culture. It was observed that the addition of 6%(w/v) Pluronic F-68 promoted cell growth up to 6.1% compared to control and that the use of 4%(v/v) n-hexadecane markedly enhanced cell growth up to 11.4%.

• KSBB Journal
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• v.22 no.5
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• pp.322-327
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• 2007

Mineral salts in medium usually profoundly influence microorganism growth and protein synthesis. In order to produce microbial transglutaminase (MTG) with a high yield from Streptoverticillium mobaraense, we screened the minerals $CaCl_2,\;CoCl_2,\;FeSO_4,\;ZnSO_4,\;MnSO_4\;and\;CuSO_4$ for MTG fermentation. The results indicated that appropriate $FeSO_4$ concentrations could significantly promote cell growth and stimulate the production of MTG. With 15 mg/L of $FeSO_4$ added to medium, 58% improvements were noted in MTG productivity (2.24 U/mL). NaCl, $CaCl_2,\;and\;CoCl_2$ enhanced MTG productivity by less than 15%, and the optimal concentrations were determined as 1 g/L, 2 g/L, and 30 mg/L respectively. Furthermore, it was determined that 7.5 mg/L of $ZnSO_4$ in medium could augment MTG productivity by 20% and induce the stationary phase for MTG production to a period 24 hr earlier. This basic and novel discovery should result in the development of a good complement to the previously defined culture media for MTG fermentation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.3
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• pp.425-432
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• 1998

The strain producing L-lactic acid from starch was isolated from kimchi. The isolated strain was identified as a homofermentative Streptococcus sp. through its morphological, cultural, biochemical characteristics, and named Streptococcus sp. JEJ-6. Lactic acids are of two types, one L-specific and the other D-specific form in a stereospecific form. Streptococcus sp. JEJ-6 produced selectively L-lactic acid from all of the tested carbon sources. The optimum conditions for the L-lactic acid production from the isolated microorganism were determined. For the maximum yield of L-lactic acid from Streptococcus sp. JEJ-6, the cell should be harvested at the early stationary phase, and the growth temperature, pH, and NaCl concentration should be 37$^{\circ}C$, pH 7.0 and 0.1%, respectively. 4% Soluble starch as substrate and organic nitrogen sources such as peptone and yeast extract should be used for the best yield. The optimum pH of the nicotinamide adenine dinucleotide(NAD)-dependent and NAD-independent lactate dehydrogenase(LDH) activities was pH 8.5 and pH 7.0, respectively.

• Preventive Nutrition and Food Science
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• v.7 no.4
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• pp.417-420
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• 2002

A strong fibrin-specific fibrinolytic enzyme was produced from Bacillus subtilis KH-4 isolated from Deonjang, a Korean fermented soybean paste similar to Japanese miso. The addition of glucose as a carbon source resulted in the highest levels of caseinolytic and fibrinolytic activities. Likewise, the addition of yeast extract as the nitrogen source resulted in the highest caseinolytic and fibrinolytic activities (3473.2 unit and 47.4 munit, respectively), It was observed that out of all metal ion sources only calcium (chloride) enhanced caseinolytic and fibrinolytic activities, with increases of 4949.3 unit and 58.2 unit/mg, respectively. The optimal temperature for the production of the enzyme was found to be 4$0^{\circ}C$ in the optimal medium (glucose 20 g, yeast extract 5 g, CaCl$_2$l g, and NaCl 2 g). The maximum fibrinolytic activity was observed at the late stationary phase. B. subtilis KH-4 produced a fibrinolytic enzyme at 4$0^{\circ}C$, after 30 h growth, which increased up to 54 h and then remained constant. These results suggest that Deonjang has potential as a source of physiologically active anti-thromotic enzymes.

• Journal of Power Electronics
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• v.10 no.3
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• pp.313-319
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• 2010

This paper proposes a new compensation algorithm for the current measurement errors in a DFIG (Doubly Fed Induction Generator). Generally, current measurement path with current sensors and analog devices has non-ideal factors like offset and scaling errors. As a result, the dq-axis currents of the synchronous reference frame have one and two times ripple components of the slip frequency. In this paper, the main concept of the proposed algorithm is implemented by integrating the 3-phase rotor currents into the stationary reference frame to compensate for the measured current ripples in a DFIG. The proposed algorithm has several beneficial features: easy implementation, less computation time, and robustness with regard to variations in the electrical parameters. The effectiveness of the proposed algorithm is verified by several experiments.

• KSBB Journal
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• v.14 no.6
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• pp.737-741
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• 1999

Phenanthrene degrading bacteria were isolated from the petroleum contaminated soil near an oil tank. Four of 15 strains decreased surface tension of culture broth of phenanthrene-containing minimal media. H6, one of the isolated bacteria decreased surface tension of culture broth below 33 dyne/cm during growth on glucose. H6 was identified as Bacillus subtilis and biosurfactant produced by H6 was lipopeptide. The biosurfactant was produced at 0.13 g/L in the mineral medium containing 2% glucose. Critical micelle concentration(CMC) of the biosurfactant was 52 mg/L. Foaming power was similar to Tween 80 and dispersing power was superior to Tween 80m SDS and Brij30. High thermal stability and emulsion index were also observed.