• Microbiology and Biotechnology Letters
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• v.22 no.5
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• pp.515-521
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• 1994

A bacterial strain, which showed the high protease activity at low temperature and the high tolerance for the surfactant, was isolated from soil and identified as Xanthomonas sp. YL-37. The optimal temperature, initial pH, and cultivation time for the production of the alkaline protease by Xanthomonas sp. YL-37 were 20$\circC , 11.0, and 84 hours, respectively. In the jar fermenter culture of Xanthomonas sp. YL-37, the alkaline protease activity was about 15,000 DU/ml/-broth after cultivating for 108 hours. The optimal pH and temperature for the protease activity were 70$\circC and 11.0, respectively. The protease was relatively stable at the pH range of 7.0~12.0 and at the temperatures below 50$\circC . The protease activity at 20$\circC was about the level of 40% of its activity at 70$\circC . The enzyme was suggested as a serine protease because the enzyme activity was inhibited by phenylmethane sulfonyl fluoride, a serine modifier.

• Mycobiology
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• v.37 no.1
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• pp.37-42
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• 2009

Comparative effects of oyster mushrooms on plasma and fecal lipid profiles and on liver and kidney function were evaluated in hyper and normocholesterolemic rats. Feeding of hypercholesterolemic rats a 5% powder of oyster mushrooms (Pleurotus ostreatus, P. sajor-caju and P. florida) reduced the plasma total cholesterol level by 37%, 21% and 16%, respectively and reduced the triglyceride level by 45%, 24% and 14%, respectively. LDL/HDL ratio decreased by 64%, 45% and 41% for P. sajor-caju, P. ostreatus and P. florida fed rats, respectively. Mushroom feeding also reduced body weight in hypercholesterolemic rats. However, it had no adverse effect on plasma bilirubin, creatinin and urea nitrogen level. Mushroom feeding also increased the total lipid and cholesterol excretion in the feces. The present study reveals that feeding of 5% oyster mushroom powder does not have detrimental effects on the liver and kidneys rather may provide health benefits for the cardiovascular-related complication by decreasing the atherogenic lipid profiles.

• Sleep Medicine and Psychophysiology
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• v.9 no.2
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• pp.122-126
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• 2002

Objectives: The purpose of this study is to investigate the effects of the 37-hour sleep deprivation on visual discrimination using the Cybernetic Flicker Fusion Analyzer (FLIMK) and to see the correlation between this finding and various subjective scale scores. Methods: Twenty six subjects (20 men 6 women, $24.50{\pm}1.45$ years of age) participated in this study. Subjects remained awake for 37 hours under continuous surveillance. In the morning and evening of two study days, the FLIMK and the self-reporting scale of sleepiness, fatigue, anxiety and mood states were instituted. Results: In FLIMK, the flicker fusion threshold was significantly decreased after sleep deprivation (F=7.66, p=0.01). The number of trials (responses) before reaching fusion frequency threshold was significantly increased after sleep deprivation (F=13.16, p=0.001). The reduction of fusion frequency was correlated with the increase of sleepiness and fatigue (p<0.05), and the number of the trials was correlated with the scores of negative mood, anxiety, and fatigue (p<0.05). Conclusions: These results suggest that 37 hour total sleep deprivation cause the decrement in visual discrimination. The decrease of the fusion frequency after sleep deprivation was correlated with sleepiness and fatigue. Further study is needed to enlighten the biological mechanism of the decrement in visual function after sleep deprivation.

• Journal of Microbiology and Biotechnology
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• v.21 no.11
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• pp.1159-1165
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• 2011

Biodiesel is methyl and ethyl esters of long-chain fatty acids produced from vegetable oils or animal fats. Lipase enzymes have occasionally been used for the production of this biofuel. Recently, biodiesel production using immobilized lipase has received increased attention. Through enhanced stability and reusability, immobilized lipase can contribute to the reduction of the costs inherent to biodiesel production. In this study, methanol-tolerant lipase M37 from Photobacterium lipolyticum was immobilized using the cross-linked enzyme aggregate (CLEA) method. Lipase M37 has a high lysine content (9.7%) in its protein sequence. Most lysine residues are located evenly over the surface of the protein, except for the lid structure region, which makes the CLEA preparation yield quite high (~93%). CLEA M37 evidences an optimal temperature of $30^{\circ}C$, and an optimal pH of 9-10. It was stable up to $50^{\circ}C$ and in a pH range of 4.0-11.0. Both soluble M37 and CLEA M37 were stable in the presence of high concentrations of methanol, ethanol, 1-propanol, and n-butanol. That is, their activities were maintained at solvent concentrations above 10% (v/v). CLEA M37 could produce biodiesel from olive oil and alcohols such as methanol and ethanol. Additionally, CLEA M37 generated biodiesel via both 2-step methanol feeding procedures. Considering its physical stability and reusability, CLEA M37 may potentially be used as a catalyst in organic synthesis, including the biodiesel production reaction.

• Korean Journal of Microbiology
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• v.47 no.1
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• pp.92-96
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• 2011

Rhodococcus sp. strain DK17 possesses three megaplasmids (380 kb pDK1, 330 kb pDK2, and 750 kb pDK3). The alkylbenzene-degrading genes (akbABCDEF) are present on pDK2 while the phthalate operons which are duplicated are present on both pDK2 (ophA'B'C'R') and pDK3 (ophABCR). DK17 with an optimal temperature of $30^{\circ}C$ showed no growth at $37^{\circ}C$. When transferred to $30^{\circ}C$, however, the $37^{\circ}C$ culture began to grow immediately, indicating that $37^{\circ}C$ is not lethal but stressful for DK17 growth. In addition, when exposed to $37^{\circ}C$ even for a short time, a part of DK17 cells lost the ability to degrade o-xylene (a model compound of alkylbenzenes). When two hundred colonies were randomly selected for colony PCR for pDK2-specific akbC, ophC', or pDK3-specific ophC, a total of 29 colonies were found to have lost at least one of the three genes. PFGE analysis clearly showed that all the mutants have different megaplasmid profiles from that of DK17 wild type, which are divided into five different cases: Type I (10 mutants, pDK2 loss and acquisition of a new ~700 kb plasmid), Type II (9 mutants, pDK2 loss), Type III (8 mutants, pDK3 loss and acquisition of a new ~400 kb plasmid), Type IV (1 mutant, pDK3 loss), and Type V (1 mutant, pDK2 and pDK3 loss and acquisition of the ~400 kb and ~700 kb plasmids). The above results showing that growth temperature changes can induce physical changes in bacterial genomes suggest that environmental changes in habitats including temperature fluctuations affect significantly the evolution of bacteria.

• Korean Journal of Microbiology
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• v.30 no.2
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• pp.71-77
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• 1992

A 50 KD metalloprotease of Serratia marcesrens ATCC 21074 was purified by ammoniumsulfate precipitation. DEAE-cellulose ion exchange chromatography, and sephadex ti-100gel filtration. Optimal pH and temperature of enzyme were pH 8.0 and 37"C, respectively.This enzyme was stable in the ranges of 10-37$^{\circ}$C and pH 5.0--11.0. Thermal denaturationwas investigated by differential scanning calorimetry. Onset temperature of denaturationand endothermic peak temperature were 376$^{\circ}$C and 43.2"C. re:,pectively. The denaturationenthalpy was -8.4mJimg. The purified metalloprotease was ri.sistant to autodigestion for24 hr at 30$^{\circ}$C. Metalloprotease in culture supernatant was also resistant to autodigestionin this conditions. Heat-denatured enzyme. however. was rapidly digested by the nativeenzyme. The metalloprotease was stable to proteolytic digestion by mammalian proteasessuch as trypsin. a-chymotrypsin, and elastase. But the enzyme was easily digested bybacterial protease. thermolysin.bacterial protease. thermolysin.

• Journal of the East Asian Society of Dietary Life
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• v.27 no.3
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• pp.348-363
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• 2017

We analyzed the mixed culture characteristics of isolated brewing fungi obtained from Korean traditional nuruk for their development as fermentation starters. In a previous study, we selected appropriate fungi strains based on their large fungi bodies and strong enzyme activities. These fungi strains were mixed cultured under various combination of ratios, pHs and temperatures. As a result, total acidities of R. delemar mixed culture media were higher than those of A. oryzae cultured at $20^{\circ}C$ and $37^{\circ}C$. The pHs of A. luchuensis 34-1 and A. oryzae 37-7 as well as R. delemar 58-8 and A. oryzae 37-7 mixed culture media gradually increased with the culture period. On the contrary, total acidities of the mixed culture media gradually decreased. ${\alpha}-Amylase$ activities of R. delemar 26-4 and R. oryzae 82-7 mixed culture media were strong at $20^{\circ}C$ and pH 4, glucoamylase activities of R. delemar 58-8 and A. oryzae 37-7 were strong at $37^{\circ}C$, pH 3 and 1:2 ratio, and acidic protease activities of R. delemar 26-4 and A. oryzae 78-5 were strong at $20^{\circ}C$, pH 4 and 1:4 ratio. This study provides the optimal mixed culture conditions for fermentation starters based on changes in pH and total acidity, favorable enzyme activities, and fungi varieties.

• Microbiology and Biotechnology Letters
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• v.44 no.3
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• pp.349-354
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• 2016

A variety of nuruks collected in different areas in Korea were explored to isolate sixty yeast strains that was able to grow at 44℃. MBY/L1569 strain, which showed the highest growth rate, was selected and identified as Pichia farinosa (Millerozyma farinosa). The isolated strain exhibited superior resistance to heat, acid, and alkali compared with those of P. farinosa KCTC27412 as a control strain. The specific growth rate of P. farinosa MBY/L1569 at 46℃ was 0.37 ± 0.05 h⁻¹, and the highest specific growth rate of 0.50 ± 0.02 h⁻¹ was obtained when it was grown at pH 7.0 and 37℃ with 50 g/l (w/v) glucose as the carbon source. Under optimum growth conditions, strain MBY/L1569 produced ethanol 19.66 ± 0.68 g/l from glucose 50 g/l, with an approximate yield of 40%. P. farinosa MBY/L1569 was deposited at the Korean Collection for Type Cultures as pichia farinosa KCTC27753.

• Food Science and Preservation
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• v.9 no.1
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• pp.109-113
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• 2002

The purpose of this study was to investigate antioxidative and nitrite scavenging activities of extracts of Cordyceps militaris. Fruiting body and mycelia of artificially cultivated Cordyceps militaris were extracted with water and 70% ethanol. In Cordyceps militaris mycelia, electron donating ability (EDA) of water extract ranged from 37% to 47% and ethanol extract ranged from 57% to 70% at 300∼1,000 ppm. In Cordyceps militaris fruiting body, EDA of water extract and ethanol extract were similar, ranged from 19% to 48% at 300-1,000 ppm. Nitrite scavenging ability (NSA) of extracts measured at various pH (1.2, 3.0, 4.2, 6.0) was the highest at pH 1.2 and decreased with increasing pH, suggesting it is pH dependent. In Cordyceps militaris mycelia, NSA of water extract 1,000 ppm was 23% and that of ethanol extract 1,000 ppm was 37% at pH 17. In Cordyceps militaris fruiting body, NSA of water extract 1,000 ppd was 12% and that of ethanol extract 1,000 ppm was 37% at pH 1.2. EDA and NSA of Cordyceps milituis were higher in extract of mycelia than fruiting beds and higher in ethanol extract than water extract of each part.

• The Journal of the Korea Contents Association
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• v.12 no.1
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• pp.346-352
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• 2012

This study compared and analyzed fetus, newborn infant, and delivery methode of 141 women who received medical service from the first examination to the delivery in an obstetrics and gynecology specialized hospital located in Gwangmyeong, Gyeonggi-do from Jan. 2010 to Dec. 2010 and had a regular delivery after 37 weeks of pregnancy (73 non-employed and 68 employed women), depending on employment state of the subjects. The following are the results derived from the study. 1. The weight of the mothers after 37 weeks of pregnancy and the average gestational age was no statistical difference depending on the employment state. 2. In 37 weeks, the average fetal weight in the non-employed group was $2.90{\pm}0.27kg$ and the rate of small for gestational age infants was 2.75%. Meanwhile, the average fetal weight in the employed group was $2.76{\pm}0.28kg$ and the rate of small for gestational age infants was shown to be 10.3%. It is known that the fetal weight of the non-employed group was significantly higher for 37 weeks of pregnancy (p<0.05). 3. The newborn infant weight of the non-employed group was $3.42{\pm}0.43kg$ in average while that of the employed group was $3.18{\pm}0.35kg$. It is known that the newborn infant weight of the non-employed group was significantly higher (p<0.05). 4. In terms of delivery method, cesarean constituted 32.9% in the non-employed group while constituting 16.2% for the employed group. It is known that cesarean was shown to be significantly higher among the non-employed group (p<0.05).