• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.2
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• pp.84-88
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• 2008

A bacterium growing on formaldehyde as a sole carbon source was isolated by the dilution method from an enrichment culture containing formaldehyde. The isolated strain, YK-32, was identified as Pseudomonas sp. by morphological, biochemical, and genetic analyses. Pseudomonas sp. YK-32 completely degraded 0.05% formaldehyde within 24 hrs. The isolated strain had a high level of formaldehyde dehydrogenase activity, which is thought to be one of the important factors for formaldehyde degradation, when cells were cultivated in the presence of formaldehyde.

• KSBB Journal
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• v.13 no.2
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• pp.119-124
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• 1998

Twelve bacterial strains capable of growing on phenol minimal medium were isolated from iron foundry activated sludge by enrichment culture, and amount them, one isolate which was the best in cell growth and phenol degradation was selected and identified as Acinetobacter junii POH. The optimal temperature, initial pH and phenol concentration in the above medium were 3$0^{\circ}C$, 7.5 and 1000 ppm, respectively. Cell growth of Acinetobacter junii POH dramatically increased 20 hrs cultivation-time and reached a almost stationary phsae 40 hrs cultivation-time then phenol was degraded about 98%. Cell growth was inhibited y phenol at concentrations over 1500 ppm. The isolate was resistant to several antibiotics as well as various heavy metal ions. The growth-limiting log P value of Acinetobacter junii POH on organic solvents was 2.9 in the LB medium. Therefore, it is suggested that Acinetobacter junii POH could be effectively used for the biological treatment of wastewater containing the presence of heavy metal ions and organic solvents.

• Journal of Environmental Health Sciences
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• v.23 no.4
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• pp.33-38
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• 1997

Four bacterial strains able to degrade dichlorobenzene as the sole source of carbon and energy were isolated from soil by selective enrichment culture, and among them, one isolation was the best in the cell growth and identified as Pseudomonas sp. DCB3 by its morphology and physiological properties. Cell growth dramatically increased in a minimal medium containing 500ppm of dichlorobenzene was not detected any more at 72 hours after cultivation. The optimal temperature and initial pH for the growth of the isolated strain were 30$\circ$C and 7.0, respectively. Cell growth was increased by supplementing $(NH_2)_2CO$ and 50 ppm yeast extract as additional nutrients. Therefore, it was suggested that Pseudomonas sp. DCB3 could be effectively used for the biological treatment of wastewater containing dichlorobenzene.

• Korean Journal of Microbiology
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• v.45 no.2
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• pp.140-147
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• 2009

In this study, anaerobic enrichment cultivation was performed with the sediments from the Gimpo and Inchon areas. Lactate as an electron donor and PCE as an electron acceptor was injected into the serum bottle with an anaerobic medium. After the incubation of 8 weeks, the reductive dechlorination of PCE was observed in 7 sites among 16 sites (43%). Three enrichment cultures showed completely dechlorination of PCE to ethene, while four enrichment culture showed transformation of PCE to cis-DCE. The bacterial community structure was analyzed by PCR-DGGE. Dechlorinating bacteria were detected by species-specific primers. The dominant species in seven anaerobic enrichments were found to belong to the genus of Dehalococcoides sp. and Geobacter sp., and Dehalobacter sp.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.4
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• pp.325-331
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• 2011

Nonylphenol (NP), which is well known as an endocrine disrupter, has been detected widely in untreated sewage or waste water streams. Given the necessity of discovering an eco-friendly method of degrading this toxic organic compound, this study was conducted to isolate NP-degrading microorganisms from the aqueous environment. NP-degrading microbes were isolated through NP-containing enrichment culture. Finally, a microbial consortium, SW-3, capable of degrading NP with high efficiency, was selected from the mixture sample. The microbial consortium SW-3 was able to degrade over 99% of 100 ppm NP in the culture medium for 40 days at $25^{\circ}C$. The microbial consortium SW-3 seemed to utilize NP as a carbon source, since NP was the sole carbon source in the culture medium. In order to isolate the NP-degrading bacterium, we further conducted single colony isolation using the microbial consortium SW-3. Four strains isolated from SW-3 exhibited lower NP-degradation efficiency than that of SW-3, suggesting that NP was degraded by the co-metabolism of the microbial consortium. We suggest that the microbial consortium obtained in this study would be useful in developing an eco-friendly bioremediation technology for NP degradation.

• Microbiology and Biotechnology Letters
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• v.44 no.3
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• pp.324-332
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• 2016

A bacterial strain capable of hydrolyzing xylan was isolated from fermented soybean paste obtained from a domestic Buddhist temple, using enrichment culture with rice straw as a carbon source. The isolate, named YB-1301, was identified as Bacillus safensis on the basis of its DNA gyrase subunit B gene (gyrB) sequence. The xylanase productivity of strain YB-1301 was drastically increased when it was grown in the presence of wheat bran or various xylans. In particular, the maximum xylanase productivity reached above 340 U/ml in the culture filtrate from LB broth supplemented with only birchwood xylan at shake-flask level. The xylanase production was significantly induced by xylans at the stationary growth phase in LB medium containing xylan, whereas only a small amount of xylanase was constitutively produced from cells grown in LB medium with no addition of xylan. Furthermore, xylanase biosynthesis was induced more rapidly by the enzymatically hydrolyzed products of xylan than by the non-hydrolyzed xylan. In addition, the xylanase in the culture filtrate of B. safensis YB-1301 was found to have optimal activity at 55℃ and pH 6.5–7.0.

• Microbiology and Biotechnology Letters
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• v.18 no.3
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• pp.273-279
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• 1990

For poly- $\beta$ -hydroxybutyrate (PHB) production, a pink-pigmented facultative methylotrophic bacterium (PPFM) P-10 was newly isolated from soils through methanol-enrichment culture. The optimal medium composition for cell growth was 1.0% (vlv) of methanol as carbon source and l.Og/l of ,TEX>$NH_4Cl$, equivalent to C/N ratio of 13.2 at pH 7.0 and $30^{\circ}C$. To investigate the optimal condition for YHB accumulation, two-stage culture technique was adopted; first stage for cell growth and second stage for accumulation of PHB providing unbalanced growth conditions. The optimal PHB accumulation was 1.0% (vIv) of methanol and 0.26gll of $NH_4Cl$, C/N of 50.8 at pH 6.0. To overcome methanol inhibition on cell growth, intermittent feeding fed-batch culture technique was employed, and the cell concentration as high as 14gll with 40% of PHB was achieved. The purified PHB was identified using IR and $1^H NMR$ as homopolymer of 8hydroxybutyric acid. The absorption spectrum of extracted pink colored microbial pigment was alsa investigated.

• Microbiology and Biotechnology Letters
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• v.39 no.3
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• pp.252-258
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• 2011

A bacterial strain capable of hydrolyzing xylan and locust bean gum (LBG) was isolated from farm soil by enrichment culture using mixture of palm kernel meal (PKM) and wheat bran as carbon source. Nucleotide sequence of 16S rDNA amplified from the isolate YB-1107 showed high similarity with those of genus Cellulosimicrobium strains. Xylanase productivity was increased when the Cellulosimicrobium sp. YB-1107 was grown in the presence of wheat bran or oat spelt xylan, while mannanase productivity was increased drastically when grown in the presence of PKM or LBG. Particularly, maximum mannanase and xylanase activities were obtained in the culture filtrate of media containing 0.7% PKM or 1% wheat bran, respectively. Both enzyme activities were produced at stationary growth phase. Mannanase from the culture filtrate showed the highest activity at $55^{\circ}C$ and pH 6.5. Xylanase activity was optimal at $65^{\circ}C$ and pH 5.5. The predominant products resulting from the mannanase or xylanase hydrolysis were oligosaccharides for LBG or xylan, respectively. In addition, the enzymes could hydrolyze wheat bran and rice bran into oligosaccharides.

• Journal of the Korean Society of Food Culture
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• v.30 no.1
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• pp.1-7
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• 2015

Traditional cuisine reflects cooking traditions shaped by political, economic, social, cultural, and environmental conditions characterized by authenticity and uniqueness. Traditional food is not only a part of our cultural heritage but also a knowledge resource. Application of food science and technology in Korean traditional foods was reviewed from six points of view, including food preservation, fermentation, changes in food materials, utilization of food functionality, and packaging and development of cooking appliances. Books from disparate times were chosen in order to cover a wide range of materials from the past to the present. Food preservation and fermentation techniques were applied to various food materials. Combination of science and skills contributes to the accessibility of diverse food materials and better quality foods. Koreans use assorted and resilient plants, which have an abundance of functional substances such as food materials. Among cooking appliances, microwave oven and refrigerator are the most innovative products with huge influences on food eating patterns as well as lifestyle. Packaging effectively reduces post-harvest preservation losses, and better packaging has technical improvements for storage and distribution. Kimchi was chosen as an example in order to study technology from the past to the present. Availability of Kimchi cabbage, enrichment of functional ingredients, identification of useful microbial species, standardization of recipe for commercialization, prevention of texture softening, introduction of salted Kimchi cabbage and Kimchi refrigerators, and packaging were reviewed. The future of traditional foods in the market will be competitive. First, traditional foods market should be maintained to protect the diversity of food materials. Secondly, tailored foods for individuals should be considered using foods with functional properties. Information on health benefits would provide insights into health and traditional food products. Third, speedy transfer of new technology to the traditional food industry is needed to ensure food quality production and new opportunities in the market. Fourth, safety of traditional foods should be ensured without sacrificing the essential characteristics of culturally important foods. Improvement of logistics, distribution, and facility should be carried out. As demand for convenience foods increases, traditional foods should be developed into products.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.89-91
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• 2000

Polynuclear aromatic hydrocarbon (PAH) compounds are highly carcinogenic chemicals and common groundwater contaminants that are observed to persist in soils. The adherence and slow release of PAHs in soil is an obstacle to remediation and complicates the assessment of cleanup standards and risks. Biological degradation of PAHs in soil has been an area of active research because biological treatment may be less costly than conventional pumping technologies or excavation and thermal treatment. Biological degradation also offers the advantage to transform PAHs into non-toxic products such as biomass and carbon dioxide. Ample evidence exists for aerobic biodegradation of PAHs and many bacteria capable of degrading PAHs have been isolated and characterized. However, the microbial degradation of PAHs in sediments is impaired due to the anaerobic conditions that result from the typically high oxygen demand of the organic material present in the soil, the low solubility of oxygen in water, and the slow mass transfer of oxygen from overlying water to the soil environment. For these reasons, anaerobic microbial degradation technologies could help alleviate sediment PAH contamination and offer significant advantages for cost-efficient in-situ treatment. But very little is known about the potential for anaerobic degradation of PAHs in field soils. The objectives of this research were to assess: (1) the potential for biodegradation of PAH in field aged soils under denitrification conditions, (2) to assess the potential for biodegradation of naphthalene in soil microcosms under denitrifying conditions, and (3) to assess for the existence of microorganisms in field sediments capable of degrading naphthalene via denitrification. Two kinds of soils were used in this research: Harbor Point sediment (HPS-2) and Milwaukee Harbor sediment (MHS). Results presented in this seminar indicate possible degradation of PAHs in soil under denitrifying conditions. During the two months of anaerobic degradation, total PAH removal was modest probably due to both the low availability of the PAHs and competition with other more easily degradable sources of carbon in the sediments. For both Harbor Point sediment (HPS-2) and Milwaukee Harbor sediment (MHS), PAH reduction was confined to 3- and 4-ring PAHs. Comparing PAH reductions during two months of aerobic and anaerobic biotreatment of MHS, it was found that extent of PAHreduction for anaerobic treatment was compatible with that for aerobic treatment. Interestingly, removal of PAHs from sediment particle classes (by size and density) followed similar trends for aerobic and anaerobic treatment of MHS. The majority of the PAHs removed during biotreatment came from the clay/silt fraction. In an earlier study it was shown that PAHs associated with the clay/silt fraction in MHS were more available than PAHs associated with coal-derived fraction. Therefore, although total PAH reductions were small, the removal of PAHs from the more easily available sediment fraction (clay/silt) may result in a significant environmental benefit owing to a reduction in total PAH bioavailability. By using naphthalene as a model PAH compound, biodegradation of naphthalene under denitrifying condition was assessed in microcosms containing MHS. Naphthalene spiked into MHS was degraded below detection limit within 20 days with the accompanying reduction of nitrate. With repeated addition of naphthalene and nitrate, naphthalene degradation under nitrate reducing conditions was stable over one month. Nitrite, one of the intermediates of denitrification was detected during the incubation. Also the denitrification activity of the enrichment culture from MHS slurries was verified by monitoring the production of nitrogen gas in solid fluorescence denitrification medium. Microorganisms capable of degrading naphthalene via denitrification were isolated from this enrichment culture.