Korean Journal of Microbiology and Biotechnology

Online ISSN: 1598-642X
Publications
Article
An alginate-degrading bacterium, identified as Shewanella oneidensis PKA 1008 by 16S ribosomal RNA sequence analysis, was isolated from the green alga Ulva pertusa. Optimal conditions for the alginate-degrading ability of its crude enzyme were then determined. The optimal culture conditions for the growth of S. oneidensis PKA 1008 were pH 9, 2% NaCl, , and 24 hours incubation time. The crude enzyme produced by S. oneidensis PKA 1008 showed the highest alginate-degrading activity at pH 9, and produced 1.001 g of reducing sugar per liter in 3.5% (w/v) sodium alginate for 1 hour.
 
Article
In this study, we measured the anti-bacterial activity of radioisotope Lu-177 using a new laboratory instrument. The disk method used for the measurement of existing anti-bacterial antibiotics is drug diffusion into the medium. To measure the antimicrobial activity of a radioisotope, a new type of laboratory instrument is necessary to prevent the drug from spreading and the present invention was thus tested. In the medium, a space isolated separately for radioisotope injection was used to prevent the radioisotope from spreading and radioisotopes are actually injected by this system. We found that the antibacterial activity increased according to the radiation dose increases. It is expected that, through the present study, measuring the antibacterial activity of the other radioisotopes easily in the laboratory will be possible.
 
Article
Biofilm formation of multifunctional plant growth promoting rhizobacterium (PGPR), Pseudomonas fluorescens 2112 is necessary for P. fluorescens 2112 to have a positive impact on the rhizosphere of red-pepper. This study investigated whether signal molecules of the quorum sensing AHLs are produced in order to confirm biofilm formative ability. Through the use of Petri dish bioassays a blue circle formed evidence of AHLs. It was confirmed that P. fluorescens 2112 produced six-carbon-chain-long AHLs by TLC bioassay. The bacterial density of P. fluorescens 2112 on the top and bottom of pepper plant roots was estimated as and CFU/g root, respectively. P. fluorescens 2112 exist more with high-density of CFU/g soil at a depth of 1 cm but at a low-density of CFU/g soil at a depth of 5 cm, from the surface of rhizosphere soil. In addition, biofilm formation of P. fluorescens 2112 on the epidermises and the tips of the red-pepper roots were confirmed visually by SEM. Thus, the production of AHLs by P. fluorescens 2112 brings about quorum sensing signaling and the formation of biofilm on the roots which has a positive effect on economically important crops such as red-pepper by additionally producing a variety of antifungal substances and auxin.
 
Article
In the course of a study for the development of functional foods utilizing Woosul (Achyranthis radix), the components and various biological activities of Korean Woosul (AJN: Achyranthes japonica Nakai) and Chinese Woosul (ABB: Achyranthes bidentata Blume) were compared. Woosul in Korea, including AJN and ABB, are regulated and part of the Korean Pharmacopoeia. From AJN and ABB, ethanol extracts and their subsequent organic solvent fractions were prepared and their in-vitro antimicrobial, antioxidant and anti-diabetes activities were evaluated. Although AJN and ABB have no clear distinction in terms of usage in Korea, our results suggest that AJN has higher quantities of lipid-soluble components and lower amounts of water-soluble sugars than does ABB. ABB also appears to possess greater amounts of flavonoid and polyphenol substances than AJN. Analyses of biological activities showed that the fractions of AJN were more active as antibacterial agents, and possessed more pronounced -glucosidase inhibitory activities than those of the ABB fractions. However, the antioxidant activities of the ABB fractions, as determined by DPPH anion-, ABTS cation-, nitrite-scavenging activity and reducing power, were higher than those of the AJN fractions. Our results suggest that the components and bioactivity of the extracts and subsequent fractions of AJN and ABB are different. Therefore, usage of either AJN or ABB should be carefully considered, as regards their individual properties, when the active fractions of Woosul are employed in the development of functional foods or novel plant-derived medicines.
 
Article
Lactic acid bacteria (LAB) are a representative group of probiotics and used in many fermented foods and beverages. Several recent studies have shown that LAB are present in makgeolli which is a traditional Korean alcoholic beverage. However, most LAB are intolerant of more than 6% (v/v) alcohol concentrations. For this reason, alcohol-tolerant LAB are isolated from kimchi, makgeolli and nuruk using alcohol containing selective media. After being cultured in MRS broth containing 13% (v/v) alcohol, the two strains which showed the highest increasing O.D values, were finally selected. As results of 16S rRNA gene sequencing and biochemical characterization using an API kit, the two species were identified as Pediococcus acidilactici K3 and S1. In addition, the identified two strains produced bacteriocins against Staphylococcus aureus. When compared with the P. acidilactici type strain, the two selected strains possessed two to three time higher growth on 12-13% (v/v) alcohol containing MRS broth. The viability of P. acidilactici K3 and S1 when inoculated in makgeolli and stored at did not decrease through a period of one month indicating that the selected strains can be used for LAB containing makgeolli.
 
Article
For the development of hardy kiwi wine, we arranged for the post-maturity of hardy kiwi fruit, treated them with calcium carbonate and a pectinase enzyme complex, investigated the resulting physicochemical properties and conducted a sensory evaluation. The period determined for creating post-maturity in the hardy kiwi fruit was determined as 5 days storage at room temperature following maturity. During this time the yield of fruit juice was increased from 22.1% to 53.5% using 0.1% (v/v) cytolase PCL5 for 2 h at room temperature. 0.1% (w/v) calcium carbonate was also added during the process of aging, for the reduction of the sour taste. The fermentation trial of the hardy kiwi wine was prepared using water (25% or 50%), sugar (), 0.1% (w/v) , 0.1% (v/v) cytolase PCL5, (200 ppm), and yeast ( cell/ml). Fermentation then occurred for 2 weeks at . The pH value, total acidity, alcohol, and reducing sugar content of the resulting hardy kiwi wines of 25% (v/w) and 50% (v/w) water, were in a range of pH 3.4-3.7, 1.12-1.21%, 14.3-14.4%, and 15-16 g/l, respectively. Citric acid and fructose constituted the major organic acids and the free sugar of the 25% and 50% hardy kiwi wine, respectively. Volatile flavor components, including 10 kinds of esters, 8 kinds of alcohols, 5 kinds of acids, 3 kinds of others and aldehydes, were determined by GC analysis. The results of sensory evaluation demonstrated that 50% hardy kiwi wine is more palatable than 25% hardy kiwi wine.
 
Article
This study was performed to investigate the whitening effects of Lactobacillus rhamnosus in addition to its antioxidative activities. The cytotoxicity of the Lactobacillus rhamnosus was 7.6% at 10.0% (v/v) concentration. Its cytotoxicity was lower than 3.2% of Lactobacillus casei when adding the same concentration. Lactobacillus rhamnosus exhibited high antioxidative activities at 14.9% of DPPH radical scavenging activity, and a lower reducing power was measured. Lactobacillus casei exhibited relatively lower antioxidative activities at 13.4%. The tyrosinase inhibition activity of Lactobacillus rhamnosus was observed at 31.3% when adding 10.0% (v/v), as compared to 17.7% for Lactobacillus casei. Lactobacillus rhamnosus demonstrated strong inhibition activity for melanin synthesis at 58.6% when adding 10.0% (v/v), while Lactobacillus casei increased to 80.6%. It was also observed that the high antioxidative activities of Lactobacillus rhamnosus were strongly correlated to whitening activities, due to the inhibition of both tyrosinase and melanin synthesis. These results support the expanded use of lactic acid bacteria as a functional bioresources in the cosmetics industry.
 
Article
In this study, the antibacterial and antioxidative activities of Epimedium koreanum Nakai were investigated for applications as cosmetic ingredients. Minimum inhibitory concentrations (MICs) of fraction-bacterium, that showed high antibacterial activity from disc diffusion assay on human skin pathogens, were tested. The ethyl acetate fraction on Staphylococcus aureus, Bacillus subtilis, Propionibacterium acnes and 50% ethanol extract on S. aureus exhibited higher antibacterial activities than methyl paraben, well known as a preservative. The DPPH (1,1-diphenyl-2-picrylhydrazyl) scavenging activities of 3 fractions of E. koreanum Nakai were lower than (+)--tocopherol, known as a typical antioxidant. From the results of the scavenging activities of various ROS generated in systems (), 50% ethanol extract () and aglycone fraction () showed high activities similar to L-ascorbic acid (), used as reference. The cellular protective effects () on photohemolysis by generated by photosensitization reaction were tested. The cellular protective effect of 50% ethanol extract ( min) was similar to (+)--tocopherol ( min), used as reference. In particular, the of aglycone fraction results were min. This is a high cellular protective effect, more than 4 times that of (+)--tocopherol. These results indicate that E. koreanum Nakai extract, and its fractions, could be utilized as a cosmetic ingredient possessing antibacterial and antioxidative activities.
 
Article
The aim of this study was to evaluate various aspects of Vitex negundo L. leaf extract, such as the antioxidative activity, tyrosinase inhibitory effects, and inhibitory activities on -MSH induced melanogenesis, and active component analysis. The DPPH (1, 1-diphenyl-2-picrylhydrazyl) scavenging activities () of the ethyl acetate fraction and aglycone fraction of V. negundo L. leaf extract were and , respectively. A luminol-dependent chemiluminescence assay revealed that the reactive oxygen species (ROS) scavenging activity () of the aglycone fraction of V. negundo L. leaf extract on ROS generated in an - system was the most prominent at . The protective effects of the extracts fractions of V. negundo L. leaf against the rose-bengal sensitized photohemolysis of human erythrocytes were increased in a concentration dependent manner (). In particular, there were greater protective effects of the aglycone fraction on the cellular membrane than that of the fat-soluble antioxidant (+)--tocopherol. The inhibitory effects () on mushroom tyrosinase were the highest for the ethyl acetate fraction ( = ). The inhibitory effect on -MSH induced melanogenesis in B16 melanoma cells was 41.80% at of ethyl acetate fraction. Active component analyses by TLC, HPLC and LC/ESI-MS revealed luteolin and isoorientin. These results indicate that V. negundo L. leaf extract can be used as an antioxidant for ROS scavenging. Particularly, the luteolin and isoorientin of the ethyl acetate fraction may be applicable to new whitening cosmetics because of its inhibitory effect on mushroom tyrosinase and -MSH induced melanogenesis in B16 melanoma cells.
 
Article
Radish (Raphanus sativus) is a common cruciferous vegetable, and its aerial parts, called Mu-chung in Korean, have plentiful nutritional components such as vitamins, minerals and dietary fibers. Mu-chung has been used as a kimchi, a traditional Korean fermented dish, and dried Mu-chung is an important component of soups commonly consumed during winter in Korea. Since the advent of the mass production of radish in Korea, with the segregation of farm areas and towns and changing diets, Mu-chung has mostly been discarded instead of utilized. In addition, studies concerning the efficient utilization and useful bioactivities of Mu-chung are still lacking worldwide. In this study, we prepared the ethanol extract of Mu-chung and its subsequent solvent fractions. Antimicrobial, antioxidation, and anticoagulation activities were then evaluated in the hopes of developing a functional biomaterial from Korean radishes' aerial parts. The ethanol extraction yield for hot-air dried Mu-chung was 5.6%, and the fraction yields of n-hexane (H), ethylacetate (EA), butanol (B) and water residue were 25.3, 3.6, 19.4, and 51.7%, respectively. Analysis of total polyphenol and total flavonoid contents showed that the EA fraction had the highest content (97.57 and 152.91 mg/g) amongst the fractions. In antimicrobial activity assays, the H and EA fractions were effective against gram positive bacteria (Staphylococcus aureus, Listeria monocytogenes, and Bacillus subtilis), but not effective against gram negative bacteria (Escherichia coli and Pseudomonas aeruginosa). The B fraction also exhibited moderate antibacterial activity, suggesting that the extract of Mu-chung has various antibacterial components. In antioxidation activity assays, the EA fraction showed strong DPPH, ABTS and nitrite scavenging activities ( of ), including reducing power. In anticoagulation activity assays, the EA fraction demonstrated strong inhibition activity against human thrombin and prothrombin. Prominent anticoagulation activity was found in aPTT assays; the aPTT of the EA fraction was extended 15-fold compared than that of the solvent control. Our results suggest that Mu-chung is an attractive nutritional food material possessing useful bioactivities, and the EA fraction of Mu-chung could be developed as a functional food ingredient.
 
Article
In this study, the anti-oxidative and anti-obesity activities of two medicinal herb extracts, Tetrapanax papyriferus (TP) and Siegesbeckia pubescens (SP), were evaluated using DPPH radical scavenging activity assay, lipase enzyme inhibition assay, and the cell culture model system. Both methanol extracts of TP and SP showed DPPH radical scavenging activities dose-dependently, and the of DPPH radical scavenging activities of the two medicinal herbs were 65.23 and 47.79 , respectively. Furthermore, both extracts suppressed effectively lipase enzyme activity dose-dependently. Moreover, TP and SP extracts significantly suppressed adipocyte differentiation, lipid accumulation, triglyceride (TG) contents on 3T3-L1 preadipocytes in a dose-dependent manner without cytotoxicity. Their anti-obesity effect was modulated by cytidine-cytidine-adenosine-adenosine-thymidine (CCAAT)/enhancer binding proteins (), and peroxisome proliferator-activated receptor () gene and protein expressions. Furthermore, TP and SP possessed a synergistic effect on anti-obesity activity. The identification of the active compounds that confer the anti-obesity activity of TP and SP might be needed.
 
Article
In this study, the anti-oxidative, anti-inflammatory, anti-melanogenic activities of Endlicheria anomala (Nees) Mez methanol extract (EAME) were evaluated by use of in vitro assays and cell culture model systems. The results revealed that EAME scavenges various radicals such as 1,1-diphenyl-2-picryl hydrazyl hydrogen peroxide induced reactive oxygen species, and lipopolysaccharide induced nitric oxide. Furthermore, EAME induced the expression of anti-oxidative enzymes such as heme oxygenase 1, thioredoxin reductase 1, NAD(P)H dehydrogenase 1, and their upstream transcription factor, nuclear factor-E2-related factor 2. Moreover, EAME inhibited in vitro DOPA oxidation and 3-isobutyl-1-methylxanthine induced melanogenesis in B16F10 cells. Its anti-melanogenic activity will have originated from the inhibition of tyrosinase enzyme activity and melanogenesis related protein expression. Taken together, these results provide the important new insight that E. anomala possesses various biological activities such as anti-oxidative, anti-inflammatory, and anti-melanogenic. Therefore, it might be utilized as a promising material in the fields of nutraceuticals and cosmetics.
 
Article
In this study, we analyzed the anti-oxidative and anti-inflammatory activities of seven medicinal herbs. All extracts of the tested herbs, Euryale ferox Salisbury, Echinops setifer Iljin, Amomum cardamomum Linne, Tetrapanax papyriferus, Illicium verum Hook. f., Typha orientalis Presl, and Piper longum Linne, exhibited potent anti-oxidative activity as confirmed by DPPH radical scavenging capacity. Lipopolysaccharide (LPS) induced nitric oxide (NO) production, in the RAW 264.7 cell line, was also ameliorated by all extracts' treatments in a dose dependent manner. NO suppressive activity originated from the inhibition of inducible nitric oxide synthase (iNOS) protein expression by the extracts. Three extracts, E. ferox S., I. verum Hook. f., and P. longum L., possessed suppressive activity against, not only iNOS, but also cycloxygenase 2 (COX-2) protein expression. These three extracts may then serve as potential candidates for non steroidal analgesic inflammation drugs (NSAIDs). Furthermore, all extracts induced anti-oxidative enzyme, heme oxygenase 1, protein expression. Taken together, these results provide an important new insight into the fact that various medicinal herbs possess potent anti-oxidative and anti-inflammatory activities and might be utilized as promising agents in the field of health products. Further studies for the identification of the active compounds from medicinal herbs are clearly needed.
 
Article
Typha orientalis, also known as bulrush or cattail, is a perennial herbaceous plant found in freshwater wetlands and has been widely used in constructed wetlands for wastewater treatment. Recent data has revealed that SH21B, a mixture composed of seven herbs including T. orientalis, exhibited an anti-adipogenic activity by the inhibition of the expression of adipogenic regulators. However, the anti-cancer effect of T. orientalis and its molecular mechanisms remain unclear. In this study, we evaluated the anti-cancer effect and its mechanism in the methanol extract of T. orientalis (METO) on human colon carcinoma HT29 cells. It was found that METO treatment showed cytotoxic activity in a dose-dependent manner, and induced G2/M cell cycle arrest and apoptosis in HT29 cells. The induction of G2/M arrest by METO was associated with the up-regulation of phospho-Cdc2 (Tyr15), an inactive form of Cdc2 and the down-regulation of Cdc25c phosphatase. METO also induced tumor suppressor p53 and cyclin-dependent kinase inhibitor p21 (WAF1/CIP1) expression. In addition, METO-induced apoptosis was characterized by the proteolytic activation of caspase-3, degradation of poly ADP ribose polymerase (PARP), and up-regulation of death receptor FAS and pro-apoptotic Bax expression. Collectively, these results indicate that the cell cycle inhibition and apoptosis induction of METO in HT29 cells allows for the possibility of its use in anti-cancer therapies.
 
Article
Several types of mesoporous alumina adsorbents with different physical properties were prepared by spray pyrolysis and were used for the separation/purification of the anticancer agent paclitaxel. The pore diameter of the adsorbents had a greater effect than did the surface area and the pore volume on the removal of plant-derived impurities. An appropriate pore diameter (~10.8 nm) was required for effective impurity removal. At a constant pore diameter, the surface area of the adsorbent affected not only the purity but also the yield of paclitaxel. Also, increasing the surface area of the adsorbent resulted in an increase in the adsorption of paclitaxel and impurities (biomass-derived tar and wax components). Removal of these impurities was confirmed by HPLC analysis of the absorbent after the treatment and TGA of the organic substances that were bound to the adsorbent.
 
Article
An agar-hydrolyzing marine bacterium, strain GNUM08120, was isolated from Sargassum fulvellum collected from Yeongil bay of East Sea of Korea. The isolate was Gram-negative, aerobic, motile with single polar flagellum, and grew at 1-10% NaCl, pH 5.0-8.0, and . G+C content and the predominant respiratory quinone were 46.13 mol% and Q-8, respectively. The major cellular fatty acids were Summed feature 3 (24.5%), (21.7%), and (12.5%). Based on 16S rRNA gene sequence similarity and DNA-DNA hybridization analyses, strain GNUM08120 was identified as a novel subspecies of Alteromonas macleodii, designated Alteromonas macleodii subsp. GNUM08120. Production of agarase by strain GNUM08120 was likely repressed by the effect of carbon catabolite repression caused by glucose. The crude agarase prepared from 12-h culture broth of strain GNUM08120 exhibited an optimum pH and temperature for agarase activity at 7.0 and , respectively. The crude enzyme produced (neo)agarobiose, (neo)agarotetraose, and (neo)agarohexaose as the hydrolyzed product of agarose.
 
Article
In order to investigate the anticancer activity of an anti-yeast substance (AYS), a proteoglycan produced by Rhanella aquatilis AY2000, the cytotoxicity of the AYS against cancer cells was determined in vitro. The AYS was not cytotoxic to the human Jurkat T cell or the mouse sarcoma 180 cell, but was cytotoxic to the human colon cancer TH20 cell. The AYS was increasingly cytotoxic against human colon cancer cells in a dose-dependent manner at range from 62.5 to 500 . Anticancer activity by combination of the AYS and an anticancer agent was also determined. The anticancer agent combined with the AYS was shown to possess greater synergistic anticancer activity against human colon cancer cells, as compared with the anticancer agent alone.
 
Article
The thermotolerant methylotrophic yeast Hansenula polymorpha is an attractive model organism for various fundamental studies, such as the genetic control of enzymes involved in methanol metabolism, peroxisome biogenesis, nitrate assimilation, and resistance to heavy metals and oxidative stresses. In addition, H. polymorpha has been highlighted as a promising recombinant protein expression host, especially due to the availability of strong and tightly regulatable promoters. In this study, we investigated the possibility of employing human serum albumin (HSA) as the fusion tag for the secretory expression of heterologous proteins in H. polymorpha. A set of four expression cassettes, which contained the methanol oxidase (MOX) promoter, translational HSA fusion tag, and the terminator of MOX, were constructed. The expression cassettes were also designed to contain sequences for accessory elements including His8-tag, linkers, tobacco etch virus protease recognition sites (Tev), multi-cloning sites, and strep-tags. To determine the effects of the size of the HSA fusion tag on the secretory expression of the target protein, each cassette contained the HSA gene fragment truncated at a specific position based on its domain structure. By using the Green fluorescence protein gene as the reporter, the properties of each expression cassette were compared in various conditions. Our results suggest that the translational HSA fusion tag is an efficient tool for the secretory expression of recombinant proteins in H. polymorpha.
 
Article
A bacterium producing a fibrinolytic enzyme was isolated from Cheonggukjang. The bacterium was identified as a strain of Bacillus amyloliquefaciens by 16S rDNA analysis and designated as B. amyloliquefaciens HC188. The optimum culture medium appeared to be one containing 0.5% (w/v) maltose and 0.5% (w/v) soytone. Bacterial growth in the optimal medium at reached the stationary phase after 27 h of incubation and the fibrinolytic enzyme showed optimum activity at 24 h. The enzyme was purified by 20-80% ammonium sulfate precipitation, CM Sepharose fast flow ion exchange chromatography, and Sephacryl S-200HR column chromatography. Its specific activity was 38359.3 units/mg protein and the yield was 5.5% of the total activity of the crude extracts. The molecular weight was 24.7 kDa and the amino acids of the N-terminal sequence were AQSVPYGVSQIKAPA. The fibrinolytic enzyme activity had an optimum temperature of and an optimum pH of 8.0, and the enzyme was stable in the ranges and pH 6.0-8.0. Enzyme activity was increased by and but inhibited by , EDTA, and PMSF. It is suggested that the purified enzyme is a metallo-serine protease.
 
Article
The Bacillus KU801 strain, due to its potential in the field of probiotics for animal use, was isolated from chicken feces. Strain KU801 was identified as Bacillus amyloliquefaciens KU801 based on the results of 16S rRNA sequencing. Vegetative and spore cells of B. amyloliquefaciens KU801 were resistant to artificial gastric juice and artificial bile acid. B. amyloliquefaciens KU801 was found to inhibit the production of nitric oxide (NO) and increase the production of Interleukin-1 alpha (IL-1). DNA damage induced by N-methyl-Ntion of ninitroso-guanidine (MNNG) was significantly inhibited, in a dose dependent manner, by preincubating MNNG together with B. amyloliquefaciens KU801. These results demonstrate the potential use of B. amyloliquefaciens KU801 as a feed additive.
 
Article
In an effort to characterize the physicochemical properties and microbial risks associated with the soy sauce jangachi (Korean traditional pickle), 15 different home-made products, which were prepared from medicinal plants and wild edible vegetables, from head-families of Andong, Kyungsangbuk-do Province in Korea, and 6 different commercial products sold at supermarket, were investigated. The average pH of the mature soaking solutions and plants soaked in the 21 jangachi were 3.99 ± 0.38 and 3.51 ± 0.41, and the average acidity of the mature soaking solutions and soaked plants were 1.59 ± 0.54 and 1.65 ± 0.76, respectively. The average brix of the mature soaking solutions and plants soaked were 27.67 ± 8.38 and 25.61 ± 6.60, respectively. In salinity, which is a major factor in jangachi industry production, the average salinity of the mature soaking solutions and soaked plants were 7.55 ± 3.26 and 5.75 ± 2.23, respectively. In particular, the hot-peppers, eusuri, du-rup, kaet-ip, kuji-ppong, myeng-i and sancho jangachi were amongst the home-made products, and the salinity was above 8.8%, which was 2 folds-higher than that of the commercial sterilized products, and 1/3-lower than commercial non-sterilized products. The color difference and turbidity of jangachi were dependent on the plant parts used. In microbial risk assessment, the microorganisms related with food-borne disease, such as Escherichia coli, Salmonella sp, and Shigella sp., were not detected. After some time, total cell count analysis revealed that the commercial products sold at supermarkets were more vulnerable than the homemade products.
 
Article
Rhizoctonia solani and Fusarium oxysporum cause yield losses in numerous economically important crops. To develop a bio-control agent, cell free extracellular compounds (ECs) of 5 bacterial strains Burkholdria sp. L1, Pseudomonas sp. L4, Pseudomonas chlororaphis VN391, Bacillus subtilis VN21 and Enterobacter sp. VN99 from Vietnamese fields, which reduced levels of R. solani root rot in lettuces and F. oxysporum root rot in tomatoes, were investigated. In a growth chamber, ECs of all antagonists markedly enhanced the biomass of lettuces (10 to 14.1%) and tomatoes (11.38 to 13.88%). In greenhouses, the disease's severity on both crops treated with ECs of the antagonists was reduced significantly and biomass losses in the plants decreased markedly. The reduction level of R. solani root rot in lettuces was 75, 66.7, 50, and 16.7% by ECs of strains L1, L4, VN21 and VN391, respectively. The biomass of lettuces increased markedly by 29.13%, 21.67%, and 23.4% by ECs of strains L1, L4 and VN21, respectively. Similarly, the reduction levels of F. oxysporum root rot in tomatoes was 76.3, 75, 41.7 and 25% by ECs of strain L1, L4, VN21 and VN391, respectively, and the biomass was significantly enhanced by 14.42, 12.7 and 13%, respectively. The ECs of strain L1 exhibited the most effective bio-control agents to suppress R. solani and F. oxysporum.
 
Acid-tolerance and exopolysaccharide production of Leuconostoc and Weissella isolates from kimchi. 
Anti-bacterial spectra of the fractionated cell-free supernatants from Lc. mesenteroides CK0128, W. cibaria CK0633, and W. cibaria KK0797 cultures. 
Article
Twenty-three strains of Leuconostoc species and 45 strains of Weissella species inhibiting the growth of Lactobacillus sakei, one of the most populous lactic acid bacteria in over-ripened kimchi, were isolated from kimchi in our previous study. Among these hetero-fermentative 68 strains, Leuconostoc mesenteroides CK0128, Weissella cibaria CK0633, and W. cibaria KK0797 exhibited a relatively high survival rate in MRS medium, which was adjusted to pH 4.3 using an acid mixture consisting of acetic and lactic acids, and produced a large amount of exopolysaccharides. The culture supernatants of 3 strains were fractionated by a molecular weight cutter and lyophilized. The fractions with a molecular weight smaller than 3,000 Da showed antagonistic activity against Staphylococcus aureus and Lb. sakei. The anti-bacterial substances were very stable to heat treatments (, 15 min) and active at acidic conditions below pH 5. -Amylase, lipase, and proteolytic enzymes (proteinase K and pepsin) did not affect their activities. These non-proteinaceous anti-bacterial substances inhibited the growth of several food pathogens.
 
Schmatic diagram depicting the isolation process of water-extractable polysaccharides from fruiting bodies of Fomes fomentarius. Elu. 1: 20 mM Tris-HCl, 500 mM NaCl (pH 7.4), Elu. 2: 50 mM α-methyl-D-glucoside, 50 mM phosphate (pH 7.0).  
Elution profiles of crude polysaccharides (MFKF-CP) on DEAE-sepharose FF column (Cl − form φ 5 × 50 cm). The column was equilibrated with 10 mM Tris-HCl buffer (pH 7.0). Each fraction (5 ml) was analyzed quantitatively on total sugar (phenol-sulfuric acid assay), uronic acids (m-hydroxybiphenyl assay), and proteins (Bradford assay).  
Anti-complementary activities of purified MFKF polysaccharides on various concentrations. PSK (krestin) was used as the control. All values were mean ± SD (n = 3).  
Anti-complementary activities of purified MFKF-AP1α and MFKF-AP1β on various concentrations in the presence or absence of Ca ++ and Mg ++ . All values were mean ± SD (n = 3).  
Article
The five anti-complementary polysaccharides (MFKF-NP, MFKF-AP1, , and MFKF-AP2, ) were separated from hot water extracts of fruiting bodies of Fomes fomentarius by two subsequent column chromatography using DEAE-sepharose FF and Concanavalin A-sepharose 4B. The order of anti-complementary activity was MFKF-AP1 > MFKF-AP1 > MFKF-AP2 > MFKF-AP2 > MFKF-NP > Polysaccharide Krestine (PSK). Especially, MFKF-AP1 among those showed the most excellent anti-complementary activity (70% of ITCH50 value at ). The monosaccharide composition analysis by gas chromatography indicates that MFKF-AP1 and are a kind of homoxylan consisted mainly of xylose above 97%. Molecular weight of MFKF-AP1, major anti-complementary polysaccharide, was estimated to be about 12,000 by high performance liquid chromatography (HPLC). After the incubation of the serum with MFKF-AP1 in the presence or absence of and ions, its anti-complementary activity was investigated. This result indicated that MFKF-AP1 seems to be activator both on the classical and the alternative pathway of complement activation.
 
Article
Human skin is constantly exposed to environmental conditions such as UV rays, polluted air, and chemical products. UV rays, in particular, affect skin in many ways causing wrinkles, fine wrinkles, rough skin, and xeroderma through a skin aging process. The purpose of this study was to investigate the anti-wrinkling effect of Juniperus rigida Sieb., derived from a common cedar tree found the world over. Measuring the elastase to investigate wrinkling efficacy, it was shown that at a concentration level of of the two extracts, the water extract exhibited a lower than 10% inhibition activity, while the ethanol extract exhibited a 68.5% inhibition activity. Collagenase inhibition activity in the water extract and ethanol extract were 44.9% in the former and 97.2% in the latter extract, which in the case of the ethanol extract, is similar to ascorbic acid (99.6%). Moreover, measuring the biosynthesis of collagen by fibroblast, a concentration level of of ethanol extract produced 151.52% of biosynthetic promotion, proving that the ethanol extract acts as a superb anti-wrinkling agent. The result of an investigation conducted on the influence of the ethanol extract on MMP-1 caused by UVA showed that at a concentration level of of the ethanol extract of J. rigida Sieb a 67.1% inhibition activity was noted. At a concentration level of of the ethanol extract of J. rigida Sieb a 35% and 39% inhibition ratio to MMP-1 protein and mRNA were observed respectively, thereby restraining the appearance of the collagen breakdown enzyme MMP-1 and wrinkle creation by skin photo-aging.
 
Yeasts species from wild flowers in Songak Mt. and Sungsan-ilchulbong of Jeju island, Korea.
Continued.
Article
Several yeasts were isolated from flowers found in Gyonggi-do Province and Jeju island in Korea. They were then identified by a comparison of their PCR-amplified D1/D2 regions of 26S rDNA, internal transcribed spacer 1 and 2 inclusive of 5.8S rDNA, using the BLAST database. A total of fifty four yeast strains were isolated from wild flowers in Gyonggi-do and the genus Pseudozyma was noted as being dominant. A total of thirty two strains were isolated from Songaksan and Seongsan-ilchulbong in Jeju island and Sporobolomyces ruberrimus was seen to be dominant. The anti-gout xanthine oxidase inhibitory activities of the culture broths and cell-free extracts from eighty six yeast strains were then determined. The cell-free extracts of Pseudozyma hubeiensis 228-S-1 exhibited the highest xanthine oxidase inhibitory activity of 19.6%. The XOD inhibitor was also maximally produced when Pseudozyma hubeiensis 228-S-1 was cultured at for 36h in YEPD medium.
 
Article
In a previous study, we investigated the antioxidative and cellular protective effects of Parthenocissus tricuspidata stem extracts. In this study, we prepared nano-emulsion containing P. tricuspidata stem extract to improve skin permeation. The particle size of the nano-emulsion using the microfluidizer was 302 nm. Its loading efficiency was over 86%. The size distribution of the nano-emulsion took a monodispersed form and the nano-emulsion was more stable than typical emulsion without using microfluidizer during a 2 week period. In vitro skin permeation study of nano-emulsion containing P. tricuspidata stem extracts was carried out using Franz diffusion cell. The 1,3-butylene glycol used as a control group had 32.59% skin permeation efficiency. The skin permeation efficiency of the nano-emulsion was 42.47%. Also, we observed the antibacterial activity of the ethyl acetate fraction on skin flora for prospective applications as a natural antimicrobial. The ethyl acetate fraction had antibacterial activities higher than methyl paraben on Staphylococcus aureus, and Bacillus subtilis. These results indicate that nano-emulsion containing P. tricuspidata stem extracts could possess valued applications in cosmetic formulations for improving skin permeation. Also, based on the antibacterial activities on skin flora, antioxidative and cellular protective effects shown in our previous study, we suggest that P. tricuspidata stem extracts could be used as functional cosmetic materials.
 
Article
Staphylococcus aureus is a major human pathogen that produces a wide array of toxins, leading to a number of adverse symptoms. We examined 275 strains of Staphylococcus aureus isolated from various foods between 2006 and 2008 for antimicrobial susceptibility. At least 259 (94.2%) of the tested strains showed antibiotic resistant properties, and 106 (40.7%) of them showed multiple antibiotic resistance. Eleven of the tested strains were resistant to oxacillin and mec A-positive. Moreover, oxacillin-resistant strains were significantly more likely to be multi-drug resistant (p < 0.01). Of the 275 isolates tested, 24.4% were noted as being positive for slime production and 30.5% were positive for biofilm assay. Antibiotic resistance was not associated with a significantly higher prevalence of biofilm formation. Twenty strains were classified using the DiversiLab system. Most of the strains could be classified into 2 clusters and 4 unique types. All 10 mec A-positive strains (cluster I) were grouped together into the same sub-cluster. Cluster II (6 strains) was not found to be resistant to oxacillin in this study. Although the prevalence of methicillin-resistant S. aureus in food is currently low, the risk of its transmission through the food chain cannot be disregarded.
 
Vegetative cells and fruiting bodies of Corallococcus coralloides strains.  
Chromatograms showing the high-performance liquid chromatography (HPLC) results for the culture extracts of the selected C. coralloides strains. HPLC was performed using the Agilent 1260 VL Infinity Series HPLC System with a Zorbax SB-C18 column (4.6 mm × 150 mm; 5 µm). The mobile phases A and B were water and acetonitrile with 0.1% formic acid, respectively, and the gradient elution at a flow rate of 0.2 ml/min was performed as follows: 0-30 min for 5-100% B (linear gradient), 30-40 min for 100% B (isocratic gradient), and 40-50 min for 5% B (isocratic gradient). The elutes were analyzed using a variable wavelength detector at 254 nm. The peaks common to the chromatograms of the extracts from all the 6 selected strains were numbered.  
C. coralloides strains producing antimicrobial substances that inhibit the growth of S. aureus and P. aeruginosa.
Article
We prepared culture extracts of 174 Corallococcus and 207 Myxococcus strains isolated in Korea, and compared their antimicrobial activity against Candida albicans, Pseudomonas aeruginosa, and Staphylococcus aureus. The percentage of strains showing antifungal activity was lower in Corallococcus (7.5% [13 of the 174 strains]) than in Myxococcus (51.7% [107 of the 207 strains]). However, the percentage of strains exhibiting antibacterial activity was higher in Corallococcus (12.1% [21 strains]) than in Myxococcus (1% [2 strains]). The culture extracts of 6 Corallococcus strains inhibited both P. aeruginosa and S. aureus and displayed similar high-performance liquid chromatography chromatograms, although the shapes of their fruiting bodies were dissimilar. The rate of production of antibacterial substances was the highest when the strains were cultured in CYS medium for more than 6 days.
 
Article
The aim of this study was to evaluate the antimicrobial activities of Glycyrrhiza uralensis and Glycyrrhiza glabra extracts with various countries of origin. Three samples of licorice with various origins (Korea, China, and Uzbekistan) were evaluated for their antimicrobial activities against six skin microflora. The bioassay applied for determining the antimicrobial effects included the disc diffusion assay, minimum inhibitory concentration, and challenge test. The ethyl acetate fractions of G. uralensis and G. glabra extracts showed significant antimicrobial activities against two gram-positive (Bacillus subtilis, Propionibacterium acnes) and two gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacteria. These samples had much more intensive antimicrobial activities than synthetic preservatives on B. subtilis, P. acnes, and P. aeruginosa, especially. Korean licorice showed the highest antimicrobial activity amongst the samples tested. In view of the observed inhibitory features of these G. uralensis and G. glabra extracts, it is suggested that they could be used as natural antiseptics against bacterial contamination in cosmetics and foods, instead of the common synthetic preservatives currently employed.
 
Article
In this study, we investigated the antioxidant activities on HaCaT and the whitening effects on B16F1 melanoma cells of Dendropanax morbifera leaf extract. In an antioxidative activity assay using HaCaT cells, the ethyl acetate () and aglycone fractions () of the D. morbifera leaf extract didn't exhibit any characteristics of cytotoxicity. When HaCaT cells were exposed to a single large dose () of UVB, the extracts protected the cells against UVB radiation. When HaCaT cells were treated with 10 mM and rose bengal, the ethyl acetate () and aglycone () fractions protected the cells against oxidative damage in a concentration dependent manner. When the whitening effects of D. morbifera leaf extract were tested in melanoma B16/F1 cells treated with the a-melanocyte stimulating hormone (-MSH), the extracts inhibited -MSH-stimulated intra/extracellular melanogenesis in a concentration dependent manner. The inhibitory effects of the ethyl acetate and aglycone fractions of D. morbifera leaf extract were 21% and 44% at , respectively. Both are more effective than arbutin (15% at ) which is known as a whitening agent. These results indicate that fractions of the D. morbifera leaf can function as cell protectants and natural antioxidants in biological systems, particularly skins exposed to UV radiation by quenching and/or scavenging and other ROS, and protecting cells against ROS. In addition, fractions of the D. morbifera leaf can be applied to new whitening cosmetics because of their inhibitory effects on -MSH stimulated melanogenesis in B16F1 melanoma cells.
 
Coded and actual levels of the factors for four factor Box-Behnken design. 
Box-Benken experiment for the 4 variables and experimental results. 
Estimate of the response function to predict mortality(Y) from Eq. (2) by regression analysis on 6 day after spray of culture filtrate. 
Analysis of variance for quadratic model on 6 day after spray of culture filtrate. 
Article
For the maximal production of aphicidal metabolites produced by the Beauveria bassiana Bb08, statistical methods such as the Box-Behnken experimental design and response surface methodology were used. The fungal culture filtrate was sprayed towards 3-star aphids and the mortality was examined. After the statistical analysis of the aphid mortality, the optimal culture conditions were found to be a culture temperature of , medium pH 5.9, flask shaking speed of 209.0 rpm, and culture time of 5.9 days. The expected mortality on days 4, 5, and 6 after spraying the filtrate on to the aphids were 76.8%, 84.9%, and 89.4%, respectively. All 4 factors of the culture conditions significantly affected the production of the aphicidal metabolites, and the order of significance was temperature, pH, culture time and shaking speed.
 
Article
Using the different adsorption properties of ssDNA and dsDNA to GO, this study used a real time and efficient fluorescence assay to detect the enzymatic activity of the Klenow fragment with the adsorbed DNA to GO. Results showed that adsorption of fluorescein-tagged ssDNA to GO resulted in fluorescence quenching and DNA was released from GO by adding complementary DNA. In addition, fluorescence restoration was increased through a polymerization reaction by the Klenow fragment in the presence of a fluorescein-attached template, GO, and primer. Gel electrophoresis was conducted to confirm the hybridization and DNA polymerization reactions on GO.
 
Article
An unstable yet efficient phenanthrene-degrading bacterium strain Ph-3 was isolated from a petroleum-contaminated site at the Mathura Oil Refinery, India. The strain was identified as Pseudomonas sp. using a polyphasic approach. An analysis of the intermediates and assays of the degradative enzymes from a crude extract of phenanthrene-grown cells showed a novel and previously unreported pattern of 1, 2-dihydroxy naphthalene and salicylic acid production. While strain Ph-3 lost its phenanthrene- degrading potential during successive transfers on a rich medium, it maintained this trait in oligotrophic soil conditions under the stress of the pollutant and degraded phenanthrene efficiently in soil microcosms. Although the maintenance and in vitro study of unstable phenotypes are difficult and such strains are often missed during isolation, purification, and screening, these bacteria constitute a substantial fraction of the microbial community at contaminated sites and play an important role in pollutant degradation during biostimulation or monitored natural attenuation.
 
Article
In order to investigate changes in quality and enzyme activity during Chungkookjang fermentation, germinated- and nongerminated yellow soybeans were fermented by Bacillus subtilis and traditional methods. When the soybean was soaked for 6 h and then watered for 4 days with 2 h-interval at , the highest germination rate was obtained. The germinated soybeans had a higher total isoflavone () than that of the nongerminated soybeans (). Amino type nitrogen contents, protease and amylase activities were higher in germinated soybean Chungkookjang, which was fermented with B. subtilis, than nongerminated soybean Chungkookjang, which was fermented with B. subtilis and traditional methods. Reducing sugar and amino type nitrogen contents, the number of viable cells and protease and amylase activities, were higher for Chungkookjang fermented with B. subtilis, than Chungkookjang fermented by traditional methods. ALP and SOD activities in the Chungkookjang diet group were considerably higher than in the control group. AST activity in the germinated soybean Chungkookjang diet group was higher than in the nongerminated soybean Chungkookjang diet group. In conclusion, it is suggested that Chungkookjang prepared with germinated soybeans using B. subtilis D7 could be practically used as a functional product.
 
Article
The nutritional requirements for the maximum production of lipopeptides by Bacillus subtilis N7 (B. subtilis N7) were investigated and optimized using response surface methodology (RSM) under shake flask fermentation. A one-factor-at-a-time experimental setup was used to screen carbon and nitrogen sources. A Plackett-Burman design (PBD) was employed to screen the most critical variables for lipopeptides production amongst ten nutritional elements. The central composite experimental design (CCD) was finally adopted to elucidate the composition of the fermentation medium. Statistical analyses (analysis of variance, ANOVA) of the results showed that KCl, and were important components and that their interactions were strong. Lipopeptide production was predicted to reach 709.87 mg/L after a 60 h incubation using an optimum fermentation medium composed of glucose 7.5 g/L, peanut oil 1.25 g/L, 0.37 g/L, 0.75 g/L, monosodium glutamate 6.75 g/L, yeast extract and (5:3 w/w) 10 g/L, KCl 0.16 g/L, 0.24 mg/L, 0.76 mg/L, and an initial pH of 7.0. Lipopeptide production ( mg/L) in the optimized medium confirmed the validity of the predicted model.
 
Numbers of isolates from Ojingeo-jeotgal showed the growth inhibition of Vibrio parahaemolyticus ATCC17802 on marine agar added 3% NaCl. 
Article
Jeotgal is a generic term given to the high-salt-fermented seafood of Korea. This study aimed at developing an overview of the bacterial community present in Ojingeo-jeotgal, a highly consumed type of jeotgal, which is made with squid. Bacteria were isolated and purified from two samples on six different kinds of media and identified by 16S rRNA gene sequence analysis. Among the 121 total isolates, the most dominant genus was Bacillus, followed by coagulase-negative staphylococci (CNS) and lactic acid bacteria (LAB). CNS were detected in both samples, but LAB were observed in only a single sample. Six strains of Bacillus species inhibiting the growth of food pathogens, Staphylococcus aureus and Vibrio parahaemolyticus, were selected from the 121 isolates. These were found to inhibit the growth of both pathogens in addition to displaying proteolytic activities on media containing 6% NaCl and 2% skim milk.
 
Article
Three slime-forming lactic acid bacteria were isolated from traditional Korean fermented soy sauce and soybean paste and shown to produce exopolysaccharides (EPS) in sucrose media. By isolating the strains, examining their morphological characteristics and determining their 16S rDNA sequences, N58-5 and K6-7 were identified as Leuconostoc mesenteroides and N45- 10 as Leuconostoc citreum. The acid and bile tolerances of these three strains were investigated. Amongst the three lactic acid bacteria, Leuc. citreum N45-10 exhibited the highest viability ( CFU/ml) in 0.05 M sodium phosphate buffer (pH 0.3) for 2 h, in artificial gastric juice for 2 h and in 0.3%, 0.5% oxgall for 24h. Leuc. mesenteroides K6-7, N58-5 and Leuc. citreum N45- 10 were grown in sucrose liquid medium and 8.16 g/L, 3.65 g/L, 16.17 g/L of EPS was collected, respectively. The hydrolyzed EPS was analyzed by HPLC in order to determine the sugar composition of EPS. Leuc. mesenteroides K6-7 and N58-5 showed two peaks indicating glucose and fructose, thus they were determined to be hetero-type polysaccharides. Leuc. citreum N45-10 showed only the glucose polymer, indicating it to be a homo-type polysaccharide. In addition, all three lactic acid bacterial hemolysis did not demonstrate a clear zone in blood agar in the area surrounding a lactic acid bacteria colony.
 
Article
Butanol-resistant bacteria were isolated from butanol solvent. The cell growth of isolated strains declined with increasing concentrations of butanol, and isolated strain BRS02 displayed more resistance to 12.5 g/L of butanol than other isolated strains. In addition, strain BRS251, which was resistant to even higher concentrations of butanol, was developed by the mutation of BRS02 using UV. BRS251 could grow in LB medium containing up to 17.5 g/L of butanol, 32.5 g/L of propanol, or 6 g/L of pentanol, whereas the control strain Escherichia coli was found to be tolerant to 7.5 g/L of butanol, 20 g/L of propanol, or 2 g/L of pentanol. The isolated BRS02, a Gram(+) bacterium seen to have a cocci form under the microscope, grew in 6.5% NaCl. According to biochemical tests, BRS02 can metabolize and produce acid with D-galactose, D-maltose, D-mannitol, D-mannose, methyl--Dglucopyranoside, D-ribose, sucrose, or D-trehalose, as carbon sources. Also, this strain showed resistance to bacitracin, vibriostatic agent O/129, and optochin, alongside positive activities for arginine dihydrolase, -glucosidase, and urease. The BRS02 strain was identified as Staphylococcus sp. by analyses of the 16S rRNA gene, phylogenetic tree, and biochemical tests.
 
Operating conditions of HPLC for analysis of lipase inhibitor compounds from Eisenia bicyclis.
Lipase inhibitory activity of solvent extraction fractions from Eisenia bicyclis ethanol extract.
Article
This study was performed to investigate the possible use of Eisenia bicyclis (EB) ethanol extract to inhibit activity against lipase. In tests, the lipase inhibitory activity of EB ethanol extract was noted as being 43, 27, and 24% at concentrations of 5, 2.5, and 1 mg/ml, respectively. Isolation was carried out by liquid and liquid extraction, silica-gel column chromatography, and HPLC. The results showed that the lipase inhibitory activity of the ethyl acetate (EA) fraction from EB ethanol extract exhibited the strongest lipase inhibitory activity with an value of 1.31 mg/ml. The EA fraction was separated using silica-gel column chromatography and we obtained 22 sub-fractions. Amongst them, the EA1 fraction showed the highest lipase inhibitory activity with an value of 0.54 mg/ml. Eight peaks were obtained from the EA1 fraction by HPLC. Fraction 5 also showed a strong lipase inhibitory activity with an value of 0.37 mg/ml. The fraction 5 was identified as dieckol and the inhibition pattern analyzed from Lineweaver-Burk plots revealed a non-competitive inhibitor. These results suggest that EB has potential as a natural anti-obesity agent.
 
Article
Ionic liquids (ILs) have been widely recognized as environmentally benign solvents. Their unique properties, including negligible vapor pressure, non-flammability, a wide liquid range and their tunable physicochemical properties by proper selection of cations and anions, make them attractive green solvents in a variety of fields such as organic synthesis/catalysis, extraction/ separation, and electrochemistry, amongst others. In this paper, the recent technological developments and their prospects in the application of ILs in microbiology and biochemical engineering, including enzymatic reactions, protein folding/refolding and biomass dissolution, are discussed.
 
Identity of the bands obtained from 18S rRNA gene DGGE profile of SSRP. 
The removal of total nitrogen (A), total phosphorus (B), and NH 3 -N (C). Closed square; SSRP using municipal wastewater, open square; influent. First 6 days; SSRP was batch operation, after 6 days; semi-continuous operation.  
Photographs of dominant microalgae cells visualized under a light microscope × 1000 in the SSRP using municipal wastewater. Scenedesmus (A) is oval shape and Chlorella (B) is a circle. Scale bars: 10 µm.  
Dry cell weight according to the operating time of the SSRP using municipal wastewater. Closed square; DCW by SSRP using municipal wastewater, open square; DCW of influent.  
Article
A concerted effort to develop alternative forms of energy is underway due to fossil fuel shortages and its deleterious effects. Recently, bioenergy from microalgae has gained prominence and the use of municipal wastewater as a low cost alternative for a nutrient source has significant advantages. In this study, we have employed municipal wastewater directly after primary treatment (primary settling basin) in a small scale raceway pond (SSRP) for microalgal growth. Indigenous microalgae in the wastewater were encouraged to grow in the SSRP under optimal conditions. The mean removal efficiencies of TN, TP, and after 6 days were 77.77%, 63.55%, and 89.02%, respectively. The average lipid content of the microalgae was 19.51% of dry cell weight, and linolenate and linoleate (18:n) were the predominant fatty acids. The 18S rRNA gene analysis and microscopic observations of the indigenous microalgae community revealed the presence of Chlorella vulgaris and Scenedesmus obliquus as the dominant microalgae. These results indicate that untreated municipal wastewater, serving as an excellent nitrogen and phosphate source for microalgal growth, could be treated using microalgae in open raceway ponds. Moreover, microalgal biomass could be further profitable by the extraction of biodiesel.
 
Layer profile of methane concentration in up-flow biofilters (Arrow: sampling site).  
Comparison of specific methane oxidation rates. (A) Time course at each biofilter bed, (B) Specific methane oxidation rate based on g-VS of each biofilter bed.  
Article
The methane oxidation characteristics at the top and bottom layers in up-flow biofilters were investigated. Two biofilters were packed with perlite and tobermolite (biofilter A: respectively top and bottom; biofilter B: respectively bottom and top) and then compared. The methane oxidation rate was analyzed with the packed bed of the biofilter layers. The bacterial population in the biofilter was characterized using quantitative real-time PCR. For the methane oxidation rate of the biofilter A column, the perlite top part () gave a relatively higher value than the tobermolite bottom part (). For the methane oxidation rate of the biofilter B column, the tobermolite top part () provided a relatively higher value than the perlite bottom part (). The pmoA gene copy numbers, responsible for methanotrophs, in the top layer of biofilter A (1.27E+13 pmoA gene copy number/mg-VSS) was higher than in the bottom layer (3.33E+13 pmoA gene copy number/mg-VSS). However, the population of methanotrophs in biofilter B was not significantly different between the top and bottom layers. These results suggest that although the methane oxidation rates of perlite and tobermolite in the top parts of biofilter A and B were high, methanotroph populations were higher in the bottom parts of both biofilters, with a rapid decline in methane concentrations within the biofilters.
 
Article
In this study we investigated the possibility of preparing brewed brown rice makgeolli, a traditional Korean rice wine, under diverse conditions. For this purpose the physicochemical characteristics of makgeolli brewed at different temperatures, utilizing a variety of nuruks, the traditional Korean fermentation agent, were studied. The alcohol content was seen to be highest when brewing occurred at , with the nuruk TN producing 16.2%. At TN produced 14.1% alcohol content. The alcohol content was therefore higher, by about 2%, for fermentations than fermentations. Similarly, saccharifying activity was influenced by temperature and sugar content, with a higher activity seen at than at . As the fermentations progressed acidification petered out, with titratable acidity being 0.50-0.67% in all end samples. On the Hunter L, a, b scale; the a value decreased slightly, while the b value increased steadily during the fermentation process. Measurements of total organic acids were highest at , with the nuruk AK, at about 550 mg%. The content of citric acid was the highest at , being 230-310 mg% in all samples. However, more lactic acid was detected at than at . Total free amino acid was highest at , with TN at , AK at , and RJ at . Total free amino acid and essential amino acid was shown to be higher at than at . The bioactive substance -aminobutyric acid was also higher at , with TN at . From all of these results, we surmise that brown rice makgeolli manufacturing conditions are optimal at fermentation temperatures and using the nuruk TN for brewing vinegar. In addition, the nuruk used clearly affects the quality of brown rice makgeolli and an appropriate method to determine the best nuruk for various purposes should be pursued.
 
Article
Endotoxins are part of the outer membrane of the cell wall of gram-negative bacteria and are continuously released during bacterial growth. Endotoxins typically induce severe sepsis and septic shock, which cause more than 50% of mortalities. Endotoxins are easily measured in the serum by the limulus amebocyte lysate (LAL) test. However, a nonspecific result is obtained, because the high concentration of serum proteins disturbs the enzyme reaction of the LAL test. In order to solve this problem, the LAL test was performed in this study after the centrifugation of the boiled serum samples to remove the impurities. As a result, among the various conditions examined, endotoxin measurement with the LAL test was the most accurate and repeatable after centrifugation of the boiled serum at . Moreover, the endotoxin was accurately and repeatedly measured from the prepared sera of mice that had been administered an intraperitoneal injection of purified lipopolysaccharides (LPS) or E. coli. Therefore, the application of centrifugation to remove impurities from boiled serum gives an accurate measurement of endotoxins in the sera of normal subjects or patients, and this will lead to the improved diagnosis and prevention of diseases caused by endotoxins. In addition, the centrifugation of boiled serum samples should be considered and included in the development of endotoxin test kits.
 
Gene expression and purification of LLCD. SDS-PAGE analysis showed the expression level and the purity of recombinant LLCD. Lane M, protein molecular weight markers; lane 1, crude extract from E. coli harboring pHCXLLCD; lane 2, LLCD purified by HisTrap-FF column chromatography.
Determination of oligomeric state of LLCD. Molecular weight of LLCD was estimated by comparing the ratio of V e /V 0 (V e , the elution volume; V 0 , the void volume) using Superdex-200 gel permeation chromatography. The purified LLCD was drawn as a solid line, and the molecular weight markers (a dashed line) were used as the mixture of six proteins: a, thyroglobulin (669 kDa); b, apoferritin (443 kDa); c, α-amylase (200 kDa); d, alcohol dehydrogenase (150 kDa); e, bovine serum albumin (66 kDa); f, carbonic anhydrase (29 kDa).
Effect of temperature on the enzymatic activity and stability of LLCD. (A) Optimal reaction temperature of LLCD was determined on the basis of its hydrolyzing activity on β-CD. (B) Its thermal stability was also examined by measuring the residual activities after preincubation for 30 min at 35 o C (closed circles) and 40 o C (open circles), respectively.
Hydrolysis patterns of LLCD on various substrates. LLCD was reacted with 1% of each substrate. CD, β-CD; PL, pullulan; SS, soluble starch; G3, maltotriose; AC, acarbose; AG, acarviosine-glucose; S and S', standards for oligosaccharides and acarbose derivatives, respectively; reaction products with (+) or without (−) LLCD.
Abbreviations: ThMA, Thermus MAase; BHCD, alkalophilic Bacillus CDase; LLCD, Lactococcus lactis CDase b
Article
A putative cyclomaltodextrinase (LLCD) gene was cloned from the genome of Lactococcus lactis subsp. lactis KCTC 3769 (ATCC 19435), which encodes 584 amino acids with the predicted molecular mass of 68.7 kDa. KCTC 3769 shares approximately 40% of amino acid sequence identity with the CDase-family of enzymes. The dimeric enzyme with C-terminal six-histidines was heterologously expressed and purified from recombinant E. coli. LLCD showed the highest activity against -cyclodextrin (CD) at pH 7.0 and . In particular, LLCD exhibited extremely low activity against starch and pullulan, while its CD-hydrolyzing activity was about 80 times higher than starch. Due to its much higher activity on CD over starch, LLCD has been identified as a member of CDases. However, LLCD can be distinguished from the other common CDases on the basis of its extremely low hydrolyzing activity against starch, pullulan, and acarbose.
 
Article
A mannitol dehydrogenase (MDH; EC 1.1.1.67) gene was cloned from the Sinorhizobium meliloti 1021 (KCTC 2353) genome and expressed in Escherichia coli. It was seen to have an open reading frame consisting of 1,485 bp encoding 494 amino acids (about 54 kDa), which shares approximately 35-55% of amino acid sequence identity with some known long-chain dehydrogenase/ reductase family enzymes. The recombinant S. meliloti MDH (SmMDH) showed the highest activity at , and pH 7.0 (D-fructose reduction) and pH 9.0 (D-mannitol oxidation), respectively. SmMDH could catalyze the oxidative/reductive reactions between D-mannitol and D-fructose in the presence of as a coenzyme, but not with NADP+/NADPH. These results indicate that SmMDH is a typical -dependent mannitol dehydrogenase.
 
Antibody titer raised against OmpC in mice infected by various Enterobacteriaceae.
Article
Salmonella enterica serovar typhi, a Gram-negative food-borne pathogen, causes typhoid fever in humans. OmpC is an outer membrane porin of S. typhi expressed throughout the infection period. OmpC is potentially an attractive antigen for multivalent vaccines and diagnostic kit designs. In this study we combined in silico, in vitro and in vivo approaches to analyze various aspects of OmpC's antigenic properties. The conserved region, in addition to secondary and tertiary structures, and linear B cell epitopes, were predicted. A number of results obtained from in silico analyses were validated by experimental studies. OmpC was amplified, cloned and then expressed, with the recombinant protein then being purified. BALB/c mice were immunized by purified denatured OmpC. The titer of antibody was raised. Results of challenges with the pathogen revealed that the immunity is non-protective. Most of the theoretical and experimental results were in consensus. Introduced linear B cell epitopes can be employed for the design of diagnostic kits based on antigen-antibody interactions.
 
Article
In this study, the tar compounds derived from the plant cell cultures of Taxus chinensis were first identified and then quantified via gas chromatography/mass spectrometry (GC/MS) and gas chromatography (GC). 2-Picoline, 2,5-xylenol, acenaphthene, 1-methylnaphthalene and o-xylene were found to be the major tar compounds by biomass. These compounds were identified and confirmed by comparing their retention times with those of authentic compounds. Each compound also spiked with the pure standard. The contents of 2-picoline, 2,5-xylenol, acenaphthene, 1-methylnaphthalene, and o-xylene in biomass were 0.2512, 0.1586, 0.1240, 0.0942 and 0.0525 wt%, respectively. Liquid-liquid extraction and adsorbent treatment were able to remove 42% and 94% of the tars from biomass, respectivly. After hexane precipitation, all of the tars were perfectly removed.
 
Geographic coordinates of the native plants in coastal sand dune. 
Continued. 
Continued. 
The identification of endophytic fungi isolated in this study. 
Article
The coastal sand-dune plants of eight species; Argusia sibirica, Calystegia soldanella, Elymus mollis, Lithospermum zollingeri, Raphanus sativus, Salsola collina, Zoysia macrostachya, and Zoysia sinica were collected from the Shindu-ri coastal sand dune. Ninety-eight endophytic fungal strains were isolated from the roots of these plants, analyzed, and identified by sequences in their internal transcribed spacers (ITS) at the ITS1, 5.8S, and ITS2 regions. The diversity of endophytic fungi isolated from coastal sand-dune plants was confirmed with various diversity indices. The fungal strains belonged to thirteen orders: Capnodiales (3.09%), Eurotiales (70.10%), Glomerellales (1.03%), Helotiales (3.09%), Hypocreales (9.28%), Mortierellales (2.06%), Onygenales (1.03%), Ophiostomatales (1.03%), Pleosporales (1.03%), Polyporales (1.03%), Russulales (1.03%), Saccharomycetales (2.06%), and Xylariales (1.03%). Of the endophytic fungal strains collected, Penicillium (59.18% in Eurotiales) and Fusarium (5.10% in Hypocreales) were the most abundant in coastal sand-dune plants. The endophytic fungal strains isolated from C. soldanella were more diverse compared to strains from the other coastal sand-dune plants.
 
Top-cited authors
Dong-Seok Lee
  • Inje University
Hae Choon Chang
  • Chosun University
Ki-Hong Yoon
  • Woosong University
Kyung-Suk Cho
  • Ewha Womans University
Jeong-Hoon Kim
  • National Research Institute for Chemical Technology