• Environmental Engineering Research
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• 제11권3호
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• pp.127-133
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• 2006

Aerobic floc-like sludge was formed in a batch reactor and the effect of cations on the formation of aerobic floc-like sludge was studied. In order to enhance the formation (rate) of aerobic floc-like sludge, cations such as $K^+$, $Na^+$, $Ca^{2+}$, and $Mg^{2+}$ were added to the seed sludge. It was found that $Ca^{2+}$ had positive effect on the formation of floc-like sludge, as measured by sludge volume index (SVI) for settle ability. The formation of floc-like sludge was confirmed by the microscopic observation after DAPI staining. The scattered forms of sludge samples at the initial stage became aggregated to form floes after $Ca^{2+}$ addition. To ensure the functions of sludge floes in a treatment plant, the gradient of ionic species around the surfaces of floc-like sludge was monitored by ion selective microelectrodes for ${NH_4}^+,\;{NO_3}^-$, and pH. The effective concentration of $Ca^{2+}$ ion to form floc-like sludge was determined to be 750 mg/L (0.15 mg $Ca^{2+}/mg$ MLSS). Under the effective $Ca^{2+}$ condition, the SVI value was the lowest and large distribution of nitrifying bacteria at the outer surface was observed in the aerobic floc-like sludge. From the results, it was found that the calcium ion functioned as an agent for the formation of aerobic floc-like sludge, resulting in the enhanced nitrification.

• 농업과학연구
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• 제4권2호
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• pp.167-172
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• 1977

스코트랜드 National Collection of Industrial Bacteria의 3개 섬유소 분해세균에 대하여 형태적, 생리적, 및 배양적성질을 검토한 결과 NCIB 8077은 Cellulomonas sp.로, NCIB 8633 및 NCIB 8634는 Pseudomonas sp로 각각 분류되었으며 기왕에 보고된 다른 섬유소 분해세균에 대한 분류학상의 문제점을 아울러 고찰하였다.

• Journal of the Korean Wood Science and Technology
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• 제43권5호
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• pp.628-640
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• 2015

Cellulase is the key enzyme in the use of cellulose-based biomaterials. Because of its structure, cellulose is difficult to be degraded by enzymes. In order to utilize cellulose-based biomaterials efficiently, evolutionary wisdom of how to use enzymes accurately and harmoniously in a biological system is needed, such as the cellulose digestive system in animals. In this study, the symbiotic bacteria from snails, Achatina fulica, were identified and their cellulase activity was evaluated. The 16S rRNA sequence analysis of 100 aerobic bacteria showed that they belonged to 9 genus and almost half of the bacteria were Lactococcus spp. Among 100 identified strains, only two Aeromonas sp. strains showed cellulase activity. Aeromonas sp. KMBS020 had both endo-${\beta}$-glucanase and ${\beta}$-glucosidase activities but Aeromonas sp. KMBS018 had ${\beta}$-glucosidase activity only. None of the 100 bacterial colonies had any cellobiohydrolase activity.

• 대한한의학방제학회지
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• 제19권2호
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• pp.83-92
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• 2011

Objectives : This study was carried out to moniter microbial flora on freeze-dried herbal powder and identify isolated bacteria. Methods : We measured the total number of bacteria and fungi in 29 herbal powder which had made according to the guideline of KFDA. For the identification, we observed microscopic properties and carried out polymerase chain reaction(PCR). The purified DNA was analyzed by DNA sequencer. Results : Among the 29 herbal powders, the fungi were detected only one sample as unacceptable range of total aerobic bacteria. Isolated bacteria were identified as Bacillus cereus, B. subtilis, B. megaterium, B. licheniformis, Erwinia tasmaniensis, E. amylovora, and Pantoea agglomerans by 16S rDNA analysis. E. tasmaniensis was observed 20 herbal samples. Conclusions : According to above results, further studies for the effective sterilization of low herbal materials should be needed.

• 한국축산식품학회:학술대회논문집
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• 한국축산식품학회 2005년도 제36차 추계 학술발표대회
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• pp.319-323
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• 2005

Lactic acid bacteria are dominant microflora in many kinds of fermented foods. In this study, dominant microflora, especially lactic acid bacteria were isolated from salted sea food, and we determined physiological characteristics, and assayed specific property such as bacteriocin activity. The population of lactic acid bacteria as well as aerobic mesophilic counts was at the level of $10^7$ cfu /g. Total 17 strains of LAB were isolated from salted sea food sample. The phenotypic characteristics of these strains were determined followed by Bergey's Manual. And genotypic and bacteriocin activity were tested by Schillinger and $L{\ddot{u}}cke^{(7)}$.

• Journal of Microbiology and Biotechnology
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• 제11권4호
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• pp.570-576
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• 2001

Thermophilic aerobic bacteria were applied in the degradation of industrial waste activated sludge (WAS) on a laboratory scale expreiment. The performance of digestion was estimated by measuring the reduction of total suspended solids (TSS), dissolved organic carbon (DOC), and total organic carbon (TOC). Among three strains of Bacillus stearothermophilus and three strains of Thermus species, B. stearothemophilus ATCC 31197 showed the best overall efficiency level for the degradation of industrial WAS, which was collected from a wastewater treatment plant in an oil refinery factory. Industrial WAS coul be successfully detraded in a batch digestion with ATCC 31197. The stability of the digestion process with ATCC 31197 was successfully verified by semi-continuous (fill-and-draw) digestion experiment. From the results of this study, it was shown that the thermophilic aerobic digestion process with ATCC 31197 could efficiently be applied to the degradation of industrial WAS.

• 육가공
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• 통권35호겨울호
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• pp.46-55
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• 2008

본 연구의 목적은 시판 중인 스타터를 이용한 발효육제품과 스타터를 이용하지 않고 자연발효시킨 육제품의 발효 및 숙성 중 미생물학적, 이화학적인 특성에 미치는 영향을 연구하고, 원료육에서의 전자선 조사(2 kGy) 효과를 검증하고자 한다. 2 kGy로 전자선 조사한 스타터 첨가구는 발효 및 숙성 중 pH가 급격히 감소하였으며(p<0.05), 최종 pH 는 4.25를 나타내었다. 총균수와 젖산균수는 스타터 첨가에 의해 좌우되는데 발효가 진행됨에 따라 총균수와 젖산균수가 유사한 경향을 나타내었다. TBARS 값은 발효 및 숙성기간이 증가함에 따라 모든 처리구에서 증가하였다. 본 연구결과를 통해 발효육 생산 전 2 kGy로 전자선 조사처리한 경우 총균수를 감소시키고 젖산균수는 증식하는 것을 확인하였다. 조사처리 후 육에 스타터를 첨가하게 되면 발효육 생산에 매우 유용하게 이용될 수 있을 것으로 사료된다.

• 한국축산식품학회지
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• 제34권4호
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• pp.525-532
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• 2014

This study was designed to elucidate the effect of ozone exposure on the bacteria counts and oxidative properties of ground Hanwoo beef contaminated with Escherichia coli O157:H7 at refrigeration temperature. Ground beef was inoculated with 7 Log CFU/g of E. coli O157:H7 isolated from domestic pigs and was then subjected to ozone exposure ($10{\times}10^{-6}kg\;O_3h^{-1}$) at $4^{\circ}C$ for 3 d. E. coli O157:H7, total aerobic and anaerobic bacterial growth and oxidative properties including instrumental color changes, TBARS, catalase (CAT) and glutathione peroxidase (GPx) activity were evaluated. Ozone exposure significantly prohibited (p<0.05) the growths of E. coli O157:H7, total aerobic and anaerobic bacteria in ground beef samples during storage. Ozone exposure reduced (p<0.05) the CIE $a^*$ value of samples over storage time. The CIE $L^*$ and CIE $b^*$ values of the samples fluctuated over storage time, and ozone had no clear effect. Ozone exposure increased the TBARS values during 1 to 3 d of storage (p<0.05). The CAT and GPx enzyme activities were not affected by ozone exposure until 2 and 3 d of storage, respectively. This study provides information about the use of ozone exposure as an antimicrobial agent for meat under refrigerated storage. The results of this study provide a foundation for the further application of ozone exposure by integrating an ozone generator inside a refrigerator. Further studies regarding the ozone concentrations and exposure times are needed.

• 한국축산식품학회지
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• 제27권3호
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• pp.308-313
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• 2007

본 연구의 목적은 시판 중인 스타터를 이용한 발효육제품과 스타터를 이용하지 않고 자연발효시킨 육제품의 발효 및 숙성 중 미생물학적, 이화학적인 특성에 미치는 영향을 연구하고, 원료육에서의 전자선 조사(2 kGy) 효과를 검증하고자 한다. 2 kGy로 전자선 조사한 스타터 첨가구는 발효 및 숙성 중 pH가 급격히 감소하였으며(p<0.05), 최종 pH 는 4.25를 나타내었다. 총균수와 젖산균수는 스타터 첨가에 의해 좌우되는데 발효가 진행됨에 따라 총균수와 젖산균수가 유사한 경향을 나타내었다. TBARS 값은 발효 및 숙성기간이 증가함에 따라 모든 처리구에서 증가하였다. 본 연구결과를 통해 발효육 생산 전 2 kGy로 전자선 조사처리한 경우 총균수를 감소시키고 젖산균수는 증식하는 것을 확인하였다. 조사처리 후 육에 스타터를 첨가하게 되면 발효육 생산에 매우 유용하게 이용될 수 있을 것으로 사료된다.

• 한국균학회지
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• 제37권2호
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• pp.150-154
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• 2009

The diversity of microflora according to growth stage of Pleurotus ostreatus and the correlation between microbe and medium fermentation were investigated. In farmhouse I, the aerobic bacteria and fungi as longer of growing period were increased. And, thermophilic bacteria and fluorescent Pseudomonas sp. showed high density at the early stage of spawn inoculation. The thermophilic actinomycetes were distributed evenly during all the growing period, but mesophilic actinomycetes were not observed. In farmhouse II, thermophilic actinomycetes were not observed in fermented medium and density of fungi were suddenly increased at 60 days after spawn inoculation. And also, mushrooms can hardly be harvested due to Penicillium spp. After medium fermentation, density of aerobic bacteria, thermophilic bacteria, and fluorescent Pseudomonas sp. was higher at farmhouse I than those of farmhouse II. In farmhouse I, Bacillus sp. and Pseudomonas sp. dominated at early stage of mushroom growth but as time goes by, density of Bacillus sp. was higher than the others. And also, the kind of microbe showed a few at early stage of mushroom growth but increased as time goes by. In farmhouse II, Bacillus sp. was dominated at early stage of mushroom growth. And the growth of Bacillus sp. and Pseudomonas sp. showed intersect aspect each other in the farmhouse I but Bacillus sp. dominated during all growth periods in the farmhouse II.