• Journal of Microbiology and Biotechnology
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• 제14권4호
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• pp.789-795
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• 2004

A promoter-probe shuttle vector pSK1Cat was constructed for the isolation of transcriptional signal sequences from Corynebacterium glutamicum. Besides conferring resistance to kanamycin in Escherichia coli and C. glutamicum, the vector carried a promoterless cat gene to confer resistance to chloramphenicol upon insertion of the appropriate transcriptional signals in the multiple cloning site. By utilizing the vector, a series of transcriptionally active fragments were isolated from the genome of C. glutamicum. The clones, ranging from 200 bp to 1 kb in size, were grouped into 3 classes of strong, medium, and weak, based on the chloramphenicol acetyltransferase (CAT) activity and sensitivity to the chloramphenicol of the clone-carrying C. glutamicum cells. C. glutamicum cells carrying the $P_{19}$ clone, a representative in the strong class, were able to grow on minimal agar plates containing over $40 mg/mell$ chloramphenicol, and showed CAT activity of 10 m㏖/mgㆍmin, performing slightly better than the cells carrying $P_{tac}$ , a strong E. coli promoter. Subcloning analysis of the $P_{19}$ clone identified a 180 bp intergenic fragment ($P_{180}$), which was located upstream of a gene encoding a hypothetical membrane protein. The expression conferred by $P_{180}$ was not affected by either the kinds of carbon sources or changes in temperature. These properties make the $P_{180}$ clone useful for the deregulated expression of biosynthetic genes in C. glutamicum during amino acid fermentation.

• 신재생에너지
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• 제6권4호
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• pp.6-14
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• 2010

Pretreatment of cellulosic biomass is necessary before enzymatic saccharification and fermentation. Extrusion is a well established process in food industries and it can be used as a physicochemical treatment method for cellulosic biomass. Aqueous ammonia soaking treatment at mild temperatures ranging from 60 to $80^{\circ}C$ for longer reaction times has been used to preserve most of the cellulose and hemicellulose in the biomass. The objective of this study was to evaluate the effect of extrusion treatment on aqueous ammonia soaking method. Extrusion was performed with miscanthus sample conditioned to 2mm of particle size and 20% of moisture content at $200^{\circ}C$ of barrel temperature and 175rpm of screw speed. And then aqueous ammonia soaking was performed with 15%(w/w) ammonia solution at $60^{\circ}C$ for 1, 2, 4, 8, 12 hours on the extruded and raw miscanthus samples respectively. In the combined extrusion-soaking treatment, most compositions removal occurred within 1~2 hours and on a basis of 1 hour soaking treatment values, cellulose was recovered about 85% and other compositions, including hemicellulose, are removed about 50% from extruded miscanthus sample. The combined extrusion-soaking treated and soaking only treated samples were subjected to enzymatic hydrolysis using cellulase and ${\beta}$-glucosidase. The enzymatic digestibility value of combined extrusion-2 hours soaking treated sample was comparable to 12 hours soaking only treated sample. It means that extrusion treatment can shorten the conventional long reaction time of aqueous ammonia soaking. The findings suggest that the combination of extrusion and soaking is a promising pretreatment method to solve both problems for no lignin removal of extrusion and long reaction time of aqueous ammonia soaking.

• 대한미생물학회지
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• 제21권1호
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• pp.33-45
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• 1986

On hundred and forty stains of shigella cultures isolated from the twelve hygiene laboratories of cities and provincial general hospital laboratories in 1983 were tested for their resistance to thirteen antimicrobial drugs and their R-plasmid transfer. Antimicrobial drugs were used amikacin, ampicillin, cephalothin, chloramphenicol, gentamicin, kanamycin, nalidixic acid, rifampicin, streptamycin, tetracycline, tobramycin, cefoperazone and piperacillin. All strains were resistant to one or more of thirteen antimicrobial drugs but 94.3% were susceptible to amikacin, gentamicin and tobramycin of total isolated. The most strains commonly found resistance was to chloramphenicol (94%) followed by streptamycin (93%), tetracyline (92%) piperacillin (90%) ampicillin (83%), cefoperazone (42%), nalidixic acid (14%), cephalothin (17%), rifampicin (22%) and kanamycin (6%), sixty percent of strains among 140 were resistance to ampicillin, chloramphenicol, streptomycin, tetracycline at the same time. The transfer of drug resistance by conjugation was tested and ninety four strains (94.3%) were resistant to one or more drugs were found to transfer their drug resistance of E. coli. percentage of transfer frequency by conjugation was one strains (54%), the transfer frequency of drug resistance varied by donor strains and recipients, but not by selecting drugs. Resistance to nalidixic acid was not transferred by conjugation to recipients. Percentage of plasmid curing after the treatment of acriflavine, acridine orange was about 8%. Among strains cured two strains were tested compare original strains with them in biochemical properties in arginine dihydrolase and arabinose fermentation reaction. It was found to growth curves of No.2 shigella flexneri, serotype 1b, and its derivatives cured with acriflavine in $M{\ddot{u}}ller$ Hinton broth medium (pH 7.4, $38^{\circ}C$) by temperature Gradient Biophoto Recorder TN-1120 (Tokyo, Japan).

• 한국식품조리과학회지
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• 제21권4호
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• pp.399-405
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• 2005

생이스트 첨가량에 따라 증편의 기계적 품질특성을 0, 1, 2, 3 및 4일간 저장하면서 측정하였고 관능적 품질특성을 평가하였다. 증편의 높이와 부피는 생이스트 첨가율 $0.5\%$ 첨가가 가장 높아 발효가 잘 된 것으로 나타났다. 물리적 특성의 경우 견고성은 저장기간에 따라 증가하는 경향을 나타냈으며 이것은 수분함량의 감소와 전분의 노화에 기인한 것이다. 응집성과 탄력성은 저장기간에 따라 점차 감소하는 경향을 보였으며, 점착성과 씹힘성은 저장기간에 따라 증가하는 경향을 보였다. 이는 생이스트를 첨가하여 제조한 증편은 점착성과 씹힘성이 낮게 나타나 생이스트 첨가가 증편의 품질을 향상시키는 것으로 나타났다. 색도는 명도인 L값은 생이스트 첨가량이 높을수록 높게 나타났으며, 저장기간이 경과함에 따라 점차 감소하여 어두운색을 나타내었다. 적색도 a 값의 경우 저장기간에 따라 비슷한 경향을 나타내었으며, 황색도 b값은 3일 경과 후 증가하다가 그 후 감소하는 경향을 나타내었다. 관능적 품질 특성의 경우 증편의 높이와 부피 측정시 $0.5\%$가 가장 높게 나타난 것과 같이 관능검사에서도 생이스트 첨가율 $0.5\%$에서 가장 높은 관능적 평가를 얻었다.

• 한국환경농학회지
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• 제35권4호
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• pp.294-301
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• 2016

BACKGROUND: Recent studies have described the importance of microbes and enzymes that can compost food waste. This study was carried out to improve production of protease of isolated microbes from food waste. METHODS AND RESULTS: Seven bacteria isolated from various sources were screened for protease production by adding skim milk into the agar medium. About 7 microbes producing protease were tested, and strain JH-35 showed the highest protease activity among them. The strain was identified as Bacillus amyloliquefaciens JH-35 based on morphological, cultural, physiological characteristics and 16S rRNA. In the fermentation experiment, the assay B. amyloliquefaciens JH-35 showed the highest protease activity in the condition of 1% glucose, 1.5% yeast extract and 0.2%$ K_2HPO_4$. The optimal condition of culture with temperature $35^{\circ}C$, initial pH of 7 and shaking speed of 200 rpm and 24 hr. CONCLUSION: The protease of the B. amyloliquefaciens JH-35 had its activity at pH 7 and the optimal culture time was 24 hr. Also, B. amyloliquefaciens JH-35 was high salt tolerance. Our results suggest that B. amyloliquefaciens JH-35 from food waste may have the potential to degrade protein and carbohydrate in food waste.

• Journal of Applied Biological Chemistry
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• 제62권4호
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• pp.361-366
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• 2019

Isorhamnetin 3-O-glucoside는 플라보놀 그룹에 속하는 물질로서 염증이나 궤양에 효과가 있을 뿐만 아니라 신경장해, 신장병증, 망막증과 같은 당뇨합병증을 완화하는 것으로 보고되었다. Isorhamnetin 3-O-glucoside는 Tetraena aegyptia, Salsola oppositifolia, Salicornia herbacea, Sambucus ebulus와 같은 몇몇 식물에서 발견된다. 생물전환은 저렴한 화합물로부터 고부가가치 물질을 생산할 수 있는 유용한 방법이다. 본 연구에서 생물전환을 통해 quercetin으부터 isorhamnetin 3-O-glucoside를 생합성 하기 위해 두 개의 유전자(PGT E82L과, ROMT-9)를 각각의 대장균에 도입하였다. 대장균의 공조배양시스템을 이용하여 isorhamnetin 3-O-glucoside 생산 배양법의 최적화를 위해 생물전환배지, 배양온도, 세포의 혼합비율, 재조합 단백질 유도시간, 기질 공급 농도 등을 테스트하였다. 최적화된 생물전환 조건하에서 생물전환을 실시하였으며, 배양의 12시간 후 181.2 mg/L의 isorhamnetin 3-O-glucoside가 생합성 되었다. 이는 이전의 연구에서 보고된 isorhamnetin 3-O-glucosie (39.6 mg/L)의 생합성보다 4.7배 높았다.

• 한국식품과학회지
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• 제21권6호
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• pp.820-825
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• 1989

멥쌀로 동진, 삼강을, 찹쌀로 신선, 한강품종을 선택하여 유과제조실험을 하였다. 사용한 멥쌀의 amylose 함량은 가각 18.5%, 찹쌀은 2-3% 수준이었으며 수침시 $(12^{\circ}C)$ 2시간 이내에 평형 수분함량에 도달하였고 멥쌀은 30%, 찹쌀은 42%의 수화도를 보였다. 쌀 전분의 호화 개시 온도는 $64.6-67.5^{\circ}C$로서 멥쌀과 찹쌀에서 큰 차이가 없었고 유과 반데기는 RH 75-84%에서 저장하면 튀김 적정 수분함량인 11-12% 수준에서 유지 가능하였다. 멥쌀과 찹쌀로 유과를 제조, 비교한 결과 멥쌀의 평화도는 2.5-2.9ml/g(건물), 찹쌀은 9.1-10.8ml/g(건물)로 멥쌀이 유의적으로 떨어지고 반대로 경도는 유의적으로 높아졌으며 바삭바삭한 정도는 차이를 보이지 많았다. 비정상 젖산 발효균에 의하여 팽화도, 경도 등은 개선되지 않았고 튀김 기름으로는 콩기름과 미강유간에 차이가 없었다.

• Food Science and Biotechnology
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• 제18권5호
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• pp.1132-1137
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• 2009

Successive application of Saccharomyces cerevisiae DSM 70424 and Saccharomyces rouxii DSM 2535 or DSM 2531 in the production of non-alcoholic beer was investigated. The aim of the study was to consider the impact of the 2 mentioned strains of S. rouxii on the reduction of alcohol content in wort fermented at 12 or $24^{\circ}C$ for 96 hr, applying periodic aeration. The 2 S. rouxii strains were added at the $48^{th}$ hr of fermentation after thermal inactivation of S. cerevisiae cells. The greatest alcohol decrease rate was observed for the treatment containing S. rouxii DSM 2535-fermented at $24^{\circ}C$ (from 1.56 to 0.36%). The concentration of acetaldehyde, diacetyl, and 2,3-pentandione, that have a key role in appearance of 'wort' and 'buttery' off flavors, were significantly lower in S. rouxii-containing treatments fermented at $24^{\circ}C$. S. rouxii-containing treatment fermented at $24^{\circ}C$ showed slightly lower overall flavor acceptability compared to S. cerevisiae-containing treatment fermented at the same temperature. Such score was improved for the products obtained at $12^{\circ}C$.

• Mycobiology
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• 제42권4호
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• pp.368-375
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• 2014

Red ginseng (Panax ginseng), a Korean traditional medicinal plant, contains a variety of ginsenosides as major functional components. It is necessary to remove sugar moieties from the major ginsenosides, which have a lower absorption rate into the intestine, to obtain the aglycone form. To screen for microorganisms showing bioconversion activity for ginsenosides from red ginseng, 50 yeast strains were isolated from Korean traditional meju (a starter culture made with soybean and wheat flour for the fermentation of soybean paste). Twenty strains in which a black zone formed around the colony on esculin-yeast malt agar plates were screened first, and among them 5 strains having high ${\beta}$-glucosidase activity on p-nitrophenyl-${\beta}$-D-glucopyranoside as a substrate were then selected. Strain JNO301 was finally chosen as a bioconverting strain in this study on the basis of its high bioconversion activity for red ginseng extract as determined by thin-layer chromatography (TLC) analysis. The selected bioconversion strain was identified as Candida allociferrii JNO301 based on the nucleotide sequence analysis of the 18S rRNA gene. The optimum temperature and pH for the cell growth were $20{\sim}30^{\circ}C$ and pH 5~8, respectively. TLC analysis confirmed that C. allociferrii JNO301 converted ginsenoside Rb1 into Rd and then into F2, Rb2 into compound O, Rc into compound Mc1, and Rf into Rh1. Quantitative analysis using high-performance liquid chromatography showed that bioconversion of red ginseng extract resulted in an increase of 2.73, 3.32, 33.87, 16, and 5.48 fold in the concentration of Rd, F2, compound O, compound Mc1, and Rh1, respectively.

• Journal of Microbiology
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• 제44권2호
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• pp.233-242
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• 2006

The objectives of this study were to optimize submerged culture conditions of a new fungal isolate, Ganorderma resinaceum, and to enhance the production of bioactive mycelial biomass and exopolysaccharides (EPS) by fed-batch culture. The maximum mycelial growth and EPS production in batch culture were achieved in a medium containing 10 g/l glucose, 8 g/l soy peptone, and 5 mM $MnCl_2$ at an initial pH 6.0 and temperature $31^{\circ}C$. After optimization of culture medium and environmental conditions in batch cultures, a fed-batch culture strategy was employed to enhance production of mycelial biomass and EPS. Five different EPS with molecular weights ranging from 53,000 to 5,257,000 g/mole were obtained from either top or bottom fractions of ethanol precipitate of culture filtrate. A fed-batch culture of G. resinaceum led to enhanced production of both mycelial biomass and EPS. The maximum concentrations of mycelial biomass (42.2 g/l) and EPS (4.6 g/l) were obtained when 50 g/l of glucose was fed at day 6 into an initial 10 g/l of glucose medium. It may be worth attempting with other mushroom fermentation processes for enhanced production of mushroom polysaccharides, particularly those with industrial potential.