• 미생물학회지
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• 제28권4호
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• pp.283-289
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• 1990

The competence time of Streptomyces viridochromogenes for aerial mycelium formation was determined. Within 10 hrs after spore inoculation the submerged mycelium was programed to form aerial mycelium, when the former was laid on agar plate. The white aerial mycelium was formed 17-22 hrs after the transfer. Ascorbic acid oxidizing enzyme band on native gel showed chracteristic mobility change during aerial mycelium formation. Total activity of this enzyme did not show any correlation with the differentiation. The asay condition for the crude enzyme was determined. EDTA and $FeCl_{2}$ showed stimulatory effect. Approximate ratio of oxygen consumed to ascorbic acid oxidized was 1:1.

• 미생물학회지
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• 제27권4호
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• pp.373-377
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• 1989

The effects of environmental factors on the extracellular release of organic carbon by Scenedesmus qudricauda were studied. The PER (percentage extracellular release) was greater at high temperature and at high concentration of nitrogen and phosphate. The PER variation according to the change of M/P ratio showed high values at each extreme N/P ratio. This result suggested that the limitation of nitrogen or phosphorous resulted in the accumulation of carbohydrates as photosynthetic products, and the products in high concentration were excreted through algal cell membrane.

• 한국식품조리과학회지
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• 제17권3호
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• pp.224-228
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• 2001

김치를 첨가한 발효소세지의 숙성기간에 따른 pH 및 미생물학적 변화를 관찰하여 김치첨가가 발효소세지의 미생물학적 특성에 미치는 영향을 검토하였다. 상업용 starter culture 첨가소세지의 pH는 초기에 5.69였으나 점점 감소되어 5.01에 이르렀고, 김치 첨가량이 증가할수록 pH는 감소되어 fresh kimchi 10, 20%와 powder kimchi 2%좌 4% 첨가 소세지는 초기에 pH가 5.4부근이었으나 저장함에 따라 4.87까지 감소하였다. 미생물의 변화는 starter culture 첨가소세지는 초기의 총세균수, 젖산균수 그리고 효모와 곰팡이수가 김치 첨가 소세지보다 $10^{7}$ cfu/g 수준으로 낮았으나 숙성기간 중 급격하게 증가하여 $10^{10}$cfu/g 수준에 이르렀다. 김치첨가소세지는 초기부터 숙성기간 동안 총세균수, 젖산균수 그리고 효모와 곰팡이수가 김치 첨가로 인해 초기에 $10^{9}$cfu/g 수준으로 약간 높았으나 숙성기간 중 완만하게 증가하여 $10^{10}$cfu/g 수준에 이르러 발효하는 동안 미생물학적 안정성을 보였다.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2001년도 추계학술대회
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• pp.16-25
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• 2001

A genomic library of biphenyl-degrading strain Comamonas sp. SMN4 was constructed by using the cosmid vector pWE15 and introduced into Escherichia coli. Of 1,000 recombinant clones tested, two clones that expressed 2,3-dihydroxybiphenyl 1,2-dioxygenase activity were found (named pNB 1 and pNB2). From pNB1 clone, subclone pNA210, demonstrated 2,3-dihydroxybiphenyl 1,2-dioxygenase activity, is isolated. 2,3-Dihydroxybiphenyl 1,2-dioxygenase (23DBDO, BphC) is an extradiol-type dioxygenase that involved in third step of biphenyl degradation pathway. The nucleotide sequence of the Comamonas sp. SMN4 gene bphC, which encodes 23DBDO, was cloned into a plasmid pQE30. The His-tagged 23DBDO produced by a recombinant Escherichia coli, SG 13009 (pREP4)(pNPC), and purified with a Ni-nitrilotriacetic acid resin affinity column using the His-bind Qiagen system. The His-tagged 23DBDO construction was active. SDS-PAGE analysis of the purified active 23DBDO gave a single band of 32 kDa; this is in agreement with the size of the bphC coding region. The 23DBDO exhibited maximum activity at pH 9.0. The CD data for the pHs, showed that this enzyme had a typical a-helical folding structures at neutral pHs ranged from pH 4.5 to pH 9.0. This structure maintained up to pH 10.5. However, this high stable folding strucure was converted to unfolded structure in acidic region (pH 2.5) or in high pH (pH 12.0). The result of CD spectra observed with pH effects on 23DBDO activity, suggested that charge transition by pH change have affected change of conformational structure for 23DBDO catalytic reaction. The $K_m$ for 2,3-dihydroxybiphenyl, 3-metylcatechol, 4-methylcatechol and catechol was 11.7 $\mu$M, 24 $\mu$M, 50 mM and 625 $\mu$M.

• 한국식생활문화학회지
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• 제35권5호
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• pp.450-458
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• 2020

This study examined the optimal temperature and time conditions to maintain high quality Dongchimi during the fermentation and storage period. Dongchimi was fermented at low (5℃), medium (10 and 15℃), and high (20℃) temperatures until the acidity reached 0.2, 0.3, and 0.4%. respectively. From the consumer's preference test enrolling five consumers, Dongchimi fermented at 15℃ until an acidity of 0.3% (for approximately six days) was evaluated to be the optimal status because of its high score of overall acceptance, taste, and odor of consumers. To determine the optimal storage temperature of fermentation, Dongchimi was stored at three different temperatures (-1, 2, 5℃) for four weeks after fermenting at 15℃ for six days. During the storage period, most of the physicochemical properties (pH, acidity, reducing sugar content, and organic acid) and microbiological properties changed significantly in the 2 and 5℃ groups, resulting in a significant change in descriptive sensory analysis of Dongchimi. These results indicate that fermentation at 15℃ and storage at -1℃ for Dongchimi enables it to maintain the best quality for a long time.

• 생약학회지
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• 제43권3호
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• pp.257-264
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• 2012

The purpose of this study was to estimate the shelf-life of Ssanghwa-tang by long-term storage test. Experiments were conducted to evaluate the stability such as the selected physicochemical, pH, identification, heavy metal, microbiological experiment under a long-term storage test of Ssanghwa-tang. The significant change was not showed in pH, heavy metal, microbiological, identification test and quantitative analysis based on long-term storage test. The contents of albiflorin, paeoniflorin, cinnamic acid, liquiritin, and glycyrrhizin in long-term storage test were 66.8-93.1 ${\mu}g/mL$, 429.0-495.0 ${\mu}g/mL$, 3.8-4.4 ${\mu}g/mL$, 32.0-38.1 ${\mu}g/mL$, and 66.8-71.7 ${\mu}g/mL$, respectively. Shelf-lifes by 5 compounds about 3 lots at room temperature were predicted 21-37, 14-21, and 16-72 months, respectively. The suggested shelf-life would be helpful on the storage and distribution of herbal medicine.

• 한국임상수의학회지
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• 제15권1호
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• pp.156-161
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• 1998

This study investigated the microbiological changes and distribution of bacteria producing enzyme in order to change food wastes to animal feed during 6 days at room temperature. Food wastes were divided as follows: one is untreated food wastes containing 80% water content and another wastes containing 40% water content adiusted by wheat bran. During the fermentation of food wastes, Lactobacillus sp. and Streptococcus sp. were grown the top position among investigated microorganisms in both of food wastes. Numbers of total microorganisms were much more than untreated wastes during fermentation of flood wastes with 40% water content. But, Streptococcus sp. and Enterobacteriaceae from 4 to 6 days were not detected in treated wastes with 40% water contents. This fact indicated that the adiustment of water content in food waste was effective in fermentation. However, the numbers of microorganisms producing pretense were low in both treated and untreated food wastes. These results suggested that flood wastes should be treated as food wastes with 40% water content to maintain a lot of fermentative microorganisms such as Lactobacillus sp., Streptococcus sp. and yeasts together with pretense to make final animal feed.

• Journal of Microbiology
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• 제44권1호
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• pp.1-10
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• 2006

Adaptation to any undesirable change in the environment dictates the survivability of many microorganisms, with such changes generating a quick and suitable response, which guides the physiology of bacteria. During nutritional deprivation, bacteria show a stringent response, as characterized by the accumulation of (p)ppGpp, resulting in the repression of stable RNA species, such as rRNA and tRNA, with a concomitant change in colony morphology. However, genes involved in amino acid biosynthesis become over-expressed to help bacteria survive under such conditions. The survivability of pathogenic bacteria inside a host cell also depends upon the stringent response demonstrated. Therefore, an understanding of the physiology of stringent conditions becomes very interesting in regulation of the growth and persistence of such invading pathogens.

• 미생물학회지
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• 제18권1호
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• pp.1-6
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• 1980

Five species of food decay fungl, Aspergillus flavus, Asp. uiger, Penicillum sp., Botrytis cinerea, and Rhizopus stolonifer, were examined for their radio sensitivity in several suspension media. Asp. flavus, Asp. niger and Penicillum sp. have almost the same sensitivity toward gamma rays. with D value in the range of 30 to 35 K rad, whereas Botrytis cinerea has a D value of approximately 55K rad and Rhizopus stolonifer, the most re4sistant fungus studied, has a crease in their radioresistnace when compared with spores irradiated in water. Asp. flavus and penicillium sp. spores irradiated in citrate buffer at pH3-7 showed almost no change in their radisensitiity with pH, but Botryis cinerea spores showed a distinct decrease in their radioresistnace at pH 6 and 7. Penicillum sp. spores irradiated in sucrose solutions showed no sinificant change in their radioresistance. Botrytis cinerea spores displayed a higher radioresistance when they were irradiated in sucrose solution than in water.

• 한국염색가공학회지
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• 제21권5호
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• pp.1-9
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• 2009

The feasibility of earthworm protease as a new cosmetic material for human hair care was investigated. The effectiveness of the earthworm protease treatment was assessed by thickness change of hairs, optical microscope examination, aminoacid analysis, surface morphology, angular resolution analysis through methylene blue staining method and tensile strength change. The protease treated hair became thinner and the soil on the surface removed in experimental groups unlike control group. Tensile strength decreased in experimental group in which the enzymes may decompose polypeptide bonds.