• Microbiology and Biotechnology Letters
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• v.40 no.4
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• pp.333-338
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• 2012

Lichens are a symbiosis between fungi, algae and cyanobacteria. Our group recently studied the antioxidant properties of some bacterial species isolated from Arctic lichens and we confirmed that they possess high antioxidant activities. In this paper, we investigated the antioxidant capacity of 5 microorganisms newly isolated from 4 Arctic lichen species, Cladonia sp., Sterocaulon sp., Umbilicaria sp. and Cetraria sp., using various solvent extractions. We carried out 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and 2,2'-azino-bis(3-ethyl benzothiazoline-6-sulphonic acid) (ABTS) free radical scavenging activity test and ferric reducing antioxidant power (FRAP) assay. Also total phenolic and flavonoid content assays were performed. Among the bacterial culture extracts of the tested lichen-microorganisms, ethyl acetate extracts of Burkholderia sordidicola S5-B(T) had not only a high antioxidant activity (72.9%) when compared with the ascorbic acid used as the control (51.3%) in the DPPH assay, but also a high amount of phenolic content as well as flavonoid content. As a result, these lichen-microorganisms may be potentially useful sources of natural antioxidants.

• Journal of Soil and Groundwater Environment
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• v.10 no.4
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• pp.26-32
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• 2005

Surfactants can be used to enhance the mass transfer rate of hydrophobic compounds into the biologically active liquid phase, resulting in an increase in biodegradation rate of toluene. In this study, the mass transfer rate and the biocompatibility of toluene in the presence of various surfactants were evaluated. Four anionic and non ionic surfactants were tested: sodium dodecyl sulfate (SOS), TritonX-100, Tween 80, and BYK-345 (silicone surfactant). Experimental results showed that BYK-345 at the critical micelle concentration (CMC) enhanced the solubility of toluene. However, there was no increase in the solubility of toluene by SOS and TritonX-100 at their CMCs. With the addition of each surfactant into deionized water the mass transfer rate became faster than that of the case with no surfactant. A bottle study using toluene-degrading microorganisms showed that SOS seriously reduced toluene removal presumably due to the toxicity of the anionic surfactant and/or the substrate competition between the surfactant and toluene. In addition, the degradation rate of toluene was decreased in the presence of BYK-345, indicating that BYK-345 adversely affects the activity of microorganisms. However, TritonX-100 and Tween 80 did not decrease the degradation rate of toluene significantly. Rather, at the low concentration of TritonX-100 toluene degradation rate was even increased. Overall the experimental results suggest that TritonX-100 be the appropriate surfactant for enhanced biological degradation of toluene.

• Korean Journal of Microbiology
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• v.54 no.4
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• pp.428-435
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• 2018

In this study, we isolated and identified bacteria from freshwater and soil collected from Osang reservoir, to screen antimicrobial bacteria against various pathogenic bacteria. 38 strains were isolated and assigned to the class Proteobacteria (22 strains), Actinobacteria (7 strains), Bacteroidets (6 strains), and Firmicutes (3 strains) based on 16S rRNA gene sequence analysis. Among them, strain OS17 showed a good growth inhibition against 5 methicillin-resistant Staphylococcus aureus subsp. aureus strains and Bacillus cereus, Bacillus subtilis, Filobasidium neoformans. As a result of the 16S rRNA gene sequence analysis, strain OS17 show the high similarity with Burkholderia ambifaria $AMMD^T$, B. diffusa $AM747629^T$, B. tettitorii $LK023503^T$ 99.8%, 99.7%, 99.6%, respectively. We investigated cell growth and antimicrobial activity according to commercial culture medium, temperature, pH for culture optimization of strain OS17. Optimal conditions for growth and antimicrobial activity in strain OS17 were found to be: YPD medium, $35^{\circ}C$ and pH 6.5. When the strain was cultured in LB, NB, TSB, R2A media at $20^{\circ}C$ and $25^{\circ}C$, the antimicrobial activity did not show. Culture filtrate of strain OS17 showed antimicrobial activity against 5 MRSA strains, Bacillus cereus, Bacillus subtilis, and Filobasidium neoformans with inhibition zones from 2 to 8 mm. Optimal reaction time was 48 h in YPD medium, 100 rpm and 0.3 vvm in 2 L-scale fed-batch fermentation process for antimicrobial activity. Culture optimization of strain OS17 can be improved on antimicrobial activity. Therefore, the antimicrobial activity of Burkholderia sp. OS17 had potential as antibiotics for pathogens including MRSA.

• Food Science and Preservation
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• v.30 no.4
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• pp.691-702
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• 2023

This study aimed to develop high value-added mulberry (Morus alba) vinegar by fermenting mulberry with yeast and acetic acid bacteria, for using it in various foods. To select the optimal strain for mulberry fermentation, different strains were tested and Saccharomyces cerevisiae SRCM101756 and Acetobacter pasteurianus SRCM102419, exhibiting excellent alcohol and acetic acid production ability during mulberry fermentation, were selected for fermentation. Mulberry vinegar was prepared using mulberry wine and the selected acetic acid bacteria, and the physicochemical properties and physiological effects were measured. The pH was 2.98 and total acidity was 4.70% by day 9 of fermentation, establishing the possibility of developing them into vinegars for industrial use. The angiotensin-glucosidase inhibition activity of mulberry vinegar increased from 13.22% to 19.19% in the 100-fold dilution, and from 42.35% to 46.11% in the 50-fold dilution, from before fermentation to after fermentation, respectively. The angiotensin-converting enzyme inhibition activity of mulberry vinegar was found to significantly increase from 44.82% before fermentation to 63.88% after fermentation in the 25-fold dilution. Moreover, a significant increase in pancreatic lipase inhibition activity after fermentation was observed. Thus, mulberry vinegar can be used as a functional material in vinegar and other foods.

• Microbiology and Biotechnology Letters
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• v.10 no.3
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• pp.163-169
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• 1982

The possible effects in vivo on the duel usage of sinseng saponin and antibiotics were studied in vitro with microorganisms. Streptomycin.sulfate, kanamycin.sulfate and gentamycin.sulfate as being an aminoglycoside-antibiotic substance showed a general synergism by the interaction of ginseng saponin and these antibiotics. But kanamycin.sulfate and gentamycin.sulfate did not show a synergism in their original antimicrobial activity against Er-winia aroideoe. Chloramphenicol as being a benzene derivative displayed an increased antimicrobial activity by the interactions of ginseng saponin and this antibiotic against Salmonella typhi, Aerobacter aerogenes and the genus Serrotia. This antibiotic also showed the decreased antimicrobial activity against Bacillus subtilis, Bacillus megaterium and Escherichia coli, but did not show an uniform antimicrobial activity against others.

• Membrane Journal
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• v.14 no.4
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• pp.289-297
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• 2004

In this study, membranes were coupled to a sequencing batch reactor for simultaneous removal of organic matter and nitrogen, and the influences of MLSS (mixed liquor suspended solid) concentration and the sludge loading rate on membrane fouling and bioactivity were investigated. The amount of membrane fouling slightly increased with MLSS concentration at both non-aeration and aeration conditions, but effect of MLSS concentration was more significant at aeration condition. Although the effect of MLSS concentration on membrane fouling was found to be insignificant at low concentration level, extremely low sludge loading, which were generated by the maintenance of large amount of biomass in the reactor, caused severe membrane fouling, and air scouring effect decreased significantly in this condition. Specific bioactivity was constantly reduced as sludge loading rate decreased. In spite of high MLSS concentration over 17,000 mg/L, the activity of the reactor decreased at extremely low sludge loading rate presumably due to the lower oxygen transfer and the competition of biomass to deficient substrate.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.4
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• pp.307-316
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• 2009

Soil microbial activity and diversity are affected by organic sources applied to improve soil quality and fluctuate seasonally. We investigated the effects of municipal compost (MC), poultry litter (PL), and cover crops of spring oats and red clover (RC) on soil enzyme activities, and soil bacterial community-level physiological profiling (CLPP) in a Mexico silt loam in North Central Missouri, USA. Temporal patterns of these parameters were observed by periodic five soil sampling from spring to fall over a two year period. MC increased soil dehydrogenase (DH) activity consistently beginning about three months after MC application; fluorescein diacetate (FDA) hydrolytic activity significantly began to increase by the September of the first year but fluctuated during the following period. DH activity responded more directly to the amount or properties of organic residues in soils while FDA hydrolysis and CLPP were generally influenced by composition of organic sources, and enzyme activities and CLPP showed seasonal variation, which depended on organic sources and soil moisture. MC and cover crops may be useful organic sources for enhancing general soil microbial activity and altering soil microbial diversity, respectively. Because microbial activities and diversity are dynamic and subject to seasonal changes, the effects of organic amendments on these parameters should be investigated frequently during a growing season.

• Journal of the Korean Wood Science and Technology
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• v.31 no.1
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• pp.1-9
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• 2003

Antimicrobial activities of plant extractives were investigated to develop a natural fungicide. Two stilbenoids and five flavonoids were isolated from wood extractives of Hovenia dulcis (Rhamnaceae) which had been selected due to its high antifungal activity among the tested species. The chemical structures of isolated compounds were determinded as : 5-hydroxy-7-methoxyflavone, 5,7-dihydroxyflavone (chrysin), 5,7-dihydroxyflavanone (pinocembrin), 3,5,7-trihydroxyflavanone (pinobanksin), 3,4',5,7-tetrahydroxyflavanone (aromadendrin), 3-hydroxy-5-methoxystilbene and 3,5-dihydroxystilbene (pinosylvin) on the basis of Mass and NMR spectroscopic data. According to the results of antifungal test, 3-hydroxy-5-methoxystilbene was evaluated as the strongest antifungal compound among the tested compounds and next were pinocembrin and pinosylvin, but those also had high hyphal growth inhibition activities against C. parasitica, T. versicolor, T. palustris and T. viride. However, pinobanksin, 5-hydroxy-7-methoxyflavone, chrysin and aromadendrin showed very low antifungal activity. In this regard, it could inferred that high antifungal activity of wood extractives of H. dulcis were derived from 3-hydroxy-5-methoxystilbene, pinocembrin and pinosylvin, respectively.

• Proceedings of the Korean Society of Food and Cookery Science Conference
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• 2005.10a
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• pp.9-14
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• 2005

본 연구에서는 프로바이오틱스로 사용하는 유용 미생물과 식용으로 안전하게 사용 가능한 미생물 자원을 이용하여 배당체의 전환 연구를 실시하여 전환체의 새로운 생리활성 작용에 대하여 연구하였다. 연구에 사용한 주요 소재로는 인삼의 사포닌 배당체, 길경의 platycodin 배당체, 호로파의 사포닌 배당체, 칡과 두유의 이소플라본 배당체 등이었다. 사용 균주로는 bifidobacteria, lactobacilli, leuconostocs, yeasts, aspergilli 등이었다. 유산균 중에는 Bifidobacterium sp. Int-57의 전환능이 우수하였고 식용 곰팡이 중에는A. niger의 전환능이 우수하였다. 다양한 미생물 또는 효소를 이용한 전환체에 대하여 아질산 소거능, 항산화능, a-glucosidase와 a-amylase 저해능 등을 조사하였을 때 일반적으로 전환 후의 활성이 중가하였다. 길경 사포닌은 전환 후에 세포 독성이 줄어들었으며 관능성이 유의적으로 개선되었다. 결론적으로, 프로바이오틱스와 식용 미생물을 이용하여 천연물 중에 존재하는 배당체의 생리활성 및 관능성을 증가시킬 수 있어 새로운 기능성 식품의 개발에 활용할 수 있을 것이다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6B
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• pp.689-694
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• 2006

The system performance of a bioactive foam reactor (BFR), that consists of a foam column using a surfactant and a biodegradation basin containing suspended bacteria, was investigated for the treatment of gaseous toluene or a mixture of four volatile organic compounds (VOCs, benzene, toluene, p-xylene, and styrene). Overall, the BFR achieved stable VOC removal efficiencies, indicating that it can be used as a potential alternative over conventional packed-bed biofilters. Furthermore, a dynamic loading test showed that relatively constant removal was maintained at the elevated loading due to a high mass transfer rate in the foam column. However, as the inlet concentration of VOCs increased, a portion of the VOCs mass-transferred to the liquid phase was stripped out from the biodegradation basin, resulting in a decrease in the overall removal efficiency. In the BFR, the removal efficiency of the individual VOC was mainly determined depending on the biodegradation rate (styrene > toluene > benzene > p-xylene), rather than the mass transfer rate. Consequently, increases in the microbial activity and the volume of the basin could improve the overall performance of the BFR system. Further investigation on microbial activity and community dynamics is required for the BFR when subjected to high loadings of VOC mixtures.