• Journal of Life Science
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• v.7 no.1
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• pp.30-38
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• 1997

For screening thermostable $\alpha$-amylase from thermophiles, various samples from extreme environments such as hot spring and sewage near them, and compoat, wereexamined microbial growth in enrichment culture medium at 55$\circ$C on the assumption that enzymes from thermophiles are inevitable thermostable. One strain showing higher $\alpha$-amylase activity was pure cultured and designated as Bacillus sp. TR-25 from the results of morphological, cultural and physiological characteristics. The most important carbon sourses for the enzyme production were soluble starch, dextrin, potato starch and corn starch. Glucose and fructose had a catabolite repression on the enzyme production. The good nitrogen sources for the enzyme production were yeat extract, nutrient broth, tryptone, corn steep liquor and ammonium sulfate. The enzyme production was accelerated by addition of CaCl$_{2}$. $\cdot $ H$_{2}$O. The optimal medium composition for the enzyme production was soluble starch 2.0%, yeast extract 0.55, CaCl$_{2}$ $\cdot $ 2H$_{2}$O 0.015, Tween 80 0.001%, pH8.0, respectively. In jar fermenter culture, this strain shows a rapid growth and required cheaper carbon and nitrogen source. These properties are very useful to fermentation industry. The $\alpha$-amylase of this strain demonstrated a maximum activity at 80$\circ$C, pH 5.0, respectively. And calcium ion did not improve thermostability of the enzyme. At 10$0^{\circ}C$, this enzyme has 235 of relative activity. Transformation was carried out by thermophilic Bacillus sp. TR-25 genomic DNA. As a result, the transformant has increased thermostable $\alpha$-amylase activity.

• Food Science of Animal Resources
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• v.26 no.3
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• pp.402-409
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• 2006

Although microorganisms are, in fact, the most diverse and abundant type of organism on Earth, the ecological functions of microbial populations remains poorly understood. A variety of bacteria including marine Vibrios encounter numerous ecological challenges, such as UV light, predation, competition, and seasonal variations in seawater including pH, salinity, nutrient levels, temperature and so forth. In order to survive and proliferate under variable conditions, they have to develop elaborate means of communication to meet the challenges to which they are exposed. In bacteria, a range of biological functions have recently been found to be regulated by a population density-dependent cell-cell signaling mechanism known as quorum-sensing (QS). In other words, bacterial cells sense population density by monitoring the presence of self-produced extracellular autoinducers (AI). N-acylhomoserine lactone (AHL)-dependent quorum-sensing was first discovered in two luminescent marine bacteria, Vibrio fischeri and Vibrio harveyi. The LuxI/R system of V. fischeriis the paradigm of Gram-negative quorum-sensing systems. At high population density, the accumulated signalstrigger the expression of target genes and thereby initiate a new set of biological activities. Several QS systems have been identified so far. Among them, an AHL-dependent QS system has been found to control biofilm formation in several bacterial species, including Pseudomonas aeruginosa, Aeromonas hydrophila, Burkholderia cepacia, and Serratia liquefaciens. Bacterial biofilm is a structured community of bacterial cells enclosed in a self-produced polymeric matrix that adheres to an inert or living surface. Extracellular signal molecules have been implicated in biofilm formation. Agrobacterium tumefaciens strain NT1(traR, tra::lacZ749) and Chromobacterium violaceum strain CV026 are used as biosensors to detect AHL signals. Quorum sensing in lactic acid bacteria involves peptides that are directly sensed by membrane-located histidine kinases, after which the signal is transmitted to an intracellular regulator. In the nisin autoregulation process in Lactococcus lactis, the NisK protein acts as the sensor for nisin, and NisR protein as the response regulator activatingthe transcription of target genes. For control over growth and survival in bacterial communities, various strategies need to be developed by which receptors of the signal molecules are interfered with or the synthesis and release of the molecules is controlled. However, much is still unknown about the metabolic processes involved in such signal transduction and whether or not various foods and food ingredients may affect communication between spoilage or pathogenic bacteria. In five to ten years, we will be able to discover new signal molecules, some of which may have applications in food preservation to inhibit the growth of pathogens on foods.

• Microbiology and Biotechnology Letters
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• v.5 no.1
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• pp.18-23
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• 1977

Experiments were carried out to pursue the availability and the feasibility of utilizable cellulosic materials as substrate for the production of cellulosic single cell protein. The resuluts were obtained as fellows. 1. Effects of carbolydrates as a sole carton source on the growth of Cellulomonas flavigena KIST 321 were examined. The result showed that cellulose and xylose would be most utlizable for cell mass production. 2. Alkaline treated waste papers and clothes resulted in good growth of the organism than intact ones did. However the waste papers as substrate of cellulosic fermentation were not digestible, even if the meterial was treated with alkalies. 3. Rice straw, rape straw and panic grass appeared to be good substrates for the cell mass production. 4. Leaves were proved to be a good substrate for the cell mass production, but wood sawdust was hardly digested by merely alkaline treatment. 5. When cellulosic wastes as the substrate were examined into the concentration of alkaline solution, the result suggested that the best productivity of cell mass from cellulosic materials was obtained on treatment with 0.8∼1.0％ NaOH solution. 6. The productivity of cell mass was increased by washing out with water after alkaline treatment of newspaper, pine sawdust, lime sawdust and pine leaf.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.10
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• pp.1090-1097
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• 2006

The anoxic activated sludge process was applied to the treatment of industrial box-mill wastewater, which exhibited the high removal efficiencies of $90{\sim}94%$$ TCOD_{Mn}$ and $58{\sim}81%$ Color. For the design of industrial anoxic activated sludge process, Monod bio-kinetic coefficients of box-mill wastewater were estimated as follows: $K_{max}$(maximum specific substrate removal rate)=0.52 $day^{-1}$, $K_s$(half saturation constant)=314 mg/L, $K_d$(decay coefficient)=0.274 $day^{-1}$, y(microbial yield coefficient)=0.908 mg/mg, and ${\mu}_{max}$(maximum specific growth rate)=0.472 $day^{-1}$. Space loading factors for the design analysis were practically determined as the values of F/M ratio=$0.043{\sim}0.07$ kg-$TCOD_{Mn}$/kg-SS-day, BOD space loading=$0.18{\sim}0.3$ kg-$TCOD_{Mn}/m^3-day$, and ${\theta}_x=6.8{\sim}26.4$ day when considering the relationship of these loading factors with growth dynamics of microorganisms, the F/M ratio that is inversely proportional to ${\theta}_x$ should be equivalent to ${\mu}_{max}$ in units, but exhibited the significant difference between theses two values. Therefore, it is considered that high safety factors are requested in the design of anoxic activated sludge process that is based on Monod bio-kinetics of microorganism.

• Korean journal of applied entomology
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• v.37 no.2
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• pp.187-191
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• 1998

For efficient and economical production of Btrc,illus tlz~rr.ingi~r1~sstirsa in NT0423 as amicrobial-control agents, a new culture medium and culture condition were developed. Five mediadesignatzd as SWI I , SW14, SW23. SW32 and SW4I were prepared ~ : i t hv arious mixture ratio ofsoybean cake and wheat bran. It was founcl that in terms of the cell growth rate and development ofsporulation of B, thrri.il~girrl.sis strain NT0423 in all SW culture media were more efficient than those inGYS and in LB media. Total cell number in all SW media showed similar values, hut SW32 lnediilm wasthe most efficient in the development of spore, which amo~~ntetod 3.7 x 10XC FUImI. Also. at the pHranging frorn 6.2 to 7.3 in the mediiun~ no ad\:erse effect was not made in the culture of B. thur-ingicnsisstrain NT0423. The optimal volume (%) of SW32 mecliuni in a 5 1 fernientor was determined as 4 8\rolume of total niediuni. resulting ill growth (4.2 x 1OTCFUlrnl) of H. t1~~irir1,yirrz.ssit.vr ain NT0423. As H.t l i ~ t r i t ~ g iw~ a~s~ csuil~tu rcd in the shakc-flash and 5 1 fcrnientor. bacterial cells were yielded to 1 X 10"CFUIml and 5 x I O1oCFLJlml.FUIml and 5 x I O1oCFLJlml.

• Journal of Ginseng Research
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• v.35 no.2
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• pp.235-242
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• 2011

To obtain microorganisms for the microbial conversion of ginsenosides in red ginseng extract (RGE), mushroom mycelia were used for the fermentation of RGE. After fermentation, total sugar contents and polyohenol contents of the RGEs fermented with various mushrooms were not a significant increase between RGE and the ferments. But uronic acid content was relatively higher in the fermented RGEs cultured with Lentus edodes (2155.6 ${\mu}g/mL$), Phelllinus linteus (1690.9 ${\mu}g/mL$) and Inonotus obliquus 26137 and 26147 (1549.5 and 1670.7 ${\mu}g/mL$) compared to the RGE (1307.1 ${\mu}g/mL$). The RGEs fermented by Ph. linteus, Cordyceps militaris, and Grifola frondosa showed particularly high levels of total ginsenosides (20018.1, 17501.6, and 16267.0 ${\mu}g/mL$, respectively). The ferments with C. militaris (6974.2 ${\mu}g/mL$), Ph. linteus (9109.2 ${\mu}g/mL$), and G. frondosa (7023.0 ${\mu}g/mL$) also showed high levels of metabolites (sum of compound K, $Rh_1$, $Rg_5$, $Rk_1$, $Rg_3$, and $Rg_2$) compared to RGE (3615.9 ${\mu}g/mL$). Among four different RGE concentrations examined, a 20 brix concentration of RGE was favorable for the fermentation of Ph. linteus. Maximum biotransformation of ginsneoside metabolites (9395.5 ${\mu}g/mL$) was obtained after 5 days fermentation with Ph. linteus. Maximum mycelial growth of 2.6 mg/mL was achieved at 9 days, in which growth was not significantly different during 5 to 9 days fermentation. During fermentation of RGE by Ph. linteus in a 7 L fermenter, $Rg_3$, $Rg_5$, and $Rk_1$ contents showed maximum concentrations after 5 days similar to flask fermentation. These results confirm that fermentation with Ph. linteus is very useful for preparing minor ginsenoside metabolites while being safe for foods.

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1619-1627
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• 1999

Microbiological characteristics of gamma irradiated low salt squid Jeot-gal were examined. Following the fermentation periods, total bacterial cell, Lactobacillus spp., Staphylococcus spp., Streptococcus spp., Pseudomonas spp. and yeast cell number were counted on their selective media and some acid forming bacteria and Pseudomonas spp. were identified. As the gamma irradiation dose increased, the microbial density of early fermentation phase was reduced and the growth rate was delayed. The repression effects on microbiological growth by gamma irradiation were to be higher as salt concentration increased. Adequate conditions of salt concentration and gamma irradiation for low-salt squid Jeot-gal preparation were 10% and 10 kGy, respectively. Lactobacillus sp. 2, Micrococcus varians and Streptococcus sp. I were isolated from 5% salt containing squid Jeot-gal, and Micrococcus morrhuae was from 20% only while Lactobacillus plantarum and Lactobacillus brevis were widespread. Lactobacillus brevis, Pediococcus halophilus and Pseudomonas diminuta were sensitive and Lactobacillus plantarum, Micrococcus morrhuae and Pseudomonas sp. 3 were resistant to gamma irradiation. The diversity of microflora decreased as salt concentration decreased and gamma irradiation dose increased.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.3
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• pp.534-538
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• 2002

To investigate the antimicrobial effects of Scutellariae Radix extract against Vibrio parahaemolyticus from food samples, Vibrio parahaemolyticus strains isolated from Tapes philippinarum were examined for their sensitivity to Scutellariae Radix extract. Total 66 Vibrio parahaemolyticus strains were isolated from Tapes philippinarm 72 samples (91.7%). The serotypes of isolated Vibrio parahemolytics were K-I group 7 strains (10.6%), K-IV group 5 strains (7.6%), K-II group 2 strains (3.0%), K-V group 2 strains (3.0%), K-VII group 2 strains (3.0%), K-VI group 1 strains (1.5%), K-VIII group 1 strains (1.5%) and antisera UT K-group 46 strains (69.7%) on antisera agglutination test, but K-III group and K-IX group strains were not found. The growth curves of isolates showed lag phase, logarithmic phase, stationary phase and death phase as typical sigmoid curve on the shellfish samples. After 6 hours, the group containing Scutellariae Radix extract differs from the control on shellfish samples in the growth inhibition curves, and Vibrio parahaemolyticus were inhibited in more than 1000 ppm Scutellariae Radix extract. The morphological changes were observed by transmission electron microscope and the microbial cells membrane was destroyed by Scutellariae Radix extract.

• Journal of Applied Biological Chemistry
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• v.55 no.2
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• pp.117-121
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• 2012

Biological activities of the hot water and ethanol extracts from Opuntia humifusa cladodes were investigated. 1,1-diphenyl-2-picryl hadrazyl (DPPH) electron donating ability of hot water and ethanol extracts was 79.07 and 82.54%, respectively. Hot water extract generally showed better cytotoxic activity than ethanol extract against each cell line. HeLa and AGS cell lines treated with hot water extract had more than 50% cytotoxic activities. Based on the antimicrobial activities against four microbial strains, both extracts inhibited growth of Staphylococcus aureus KCCM 11593, whereas affected cell growth of three other microorganisms, Escherichia coli (KCCM 11234), Pseudomonas aeruginosa (ATCC 27853), and Salmonella typhimurium (ATCC 11862), in proportion to the concentration of extracts. The inflammatory activities against hot water extract (34.31%) showed higher than that of ethanol extract (25.59%). The effect of extracts on 3T3-L1 preadipocytes differentiation showed that differentiation of treated group with 80 and 100 ${\mu}g/mL$ of hot and ethanol extracts were increased more than treated group with isobutyl methyl xanthine (IBMX) + dexamethasone. These results indicate that the O. humifusa cladodes extracts can be used as a functional material due to their effective biological activities.

• Korean Journal of Medicinal Crop Science
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• v.21 no.5
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• pp.334-341
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• 2013

Studies were carried to evaluated the influence of storage method by temperatures and fillers on yield and quality of seed rhizome in turmeric. Seed rhizome was stored at styrofoam box filled with rice hull and sand (3:1) or vermiculite for 30, 60 and 90 days at different temperatures (5, 10 and $15^{\circ}C$. compared to traditional method (rhizome only). Parameters were obtained for weight loss, cold injury, percentage of decayed in stored rhizome during storage periods. Also, the germination, growth pattern and yield from stored rhizome has been investigated. It was confirmed that storage of turmeric in stored with filled with vermiculite helps in prevention of rhizomes from microbial and fungal attack. The storage of rhizomes in styrofoam box without any filler at low temperature below $10^{\circ}C$. is not advocated due to heavy losses weight and decayed in management of postharvest for turmeric rhizome. Germination percentage, growth pattern and yield was maximum for rhizomes stored at styrofoam box filled with vermiculite for 90 days at $15^{\circ}C$. The paper outlines a brief attempt to assess the efficacy of non-chemical methods including optimal storage method (temperature and filler) of control of decay and moisture losses during storage of turmeric.