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논문검색은 역시 페이퍼서치

한국미생물·생명공학회지검색

Microbiology and Biotechnology Letters


  • - 주제 : 자연과학분야 > 생물
  • - 성격 : 학술지
  • - 간기: 계간
  • - 국내 등재 : KCI 등재
  • - 해외 등재 : - / SCOPUS
  • - ISSN : 1598-642x
  • - 간행물명 변경 사항 : 산업미생물학회지(~2001)→한국미생물·생명공학회지(2002~)
논문제목
수록 범위 : 43권 3호 (2015)

식품 내 벤조피렌 분석법의 기존 연구동향 및 라만분광법 기반기술 전망

이미현 ( Mihyun Lee ) , 이소윤 , 김현연 ( Xuanyan Jin ) , 최대식 ( Daesik Choi ) , 이한주 ( Hanju Rhee ) , 이진규 ( Jinkyu Rhee )
4,500
초록보기
With a view to supporting the provisions of the current Korean food code for the detection of Benzo[a]pyrene, various analytical methods of detection in foods were evaluated and established in terms of linearity, limits of detection/quantitation, efficiency, and accuracy, amongst others. It was observed that to improve the technologies involved in the application of these methods, complicated and combined preparation processes of foods, including extraction, separation and purification, have been the main focus of efforts at optimization. Recently, on-site quick reaction for the detection of hazardous substances in the environment and food materials aims at developing simplified examination processes, such as lable-free and non-invasive technological analysis, to reduce the costs and time involved in the examination. Herein, current benzo[a]pyrene detection methods are reviewed in addition to new Raman spectroscopy-based trials established to pursue improve the speed, simplicity and suitability of testing.
4,500
초록보기
In this study, L. plantarum, when reacting with the culture media of potential pathogenic bacteria, exhibited an increase in growth rate and antimicrobial activity. In order to examine the characteristics and the nature of the reaction with the bacteria, this study carried out experiments involving culturing the test bacteria in M9 minimal media. Subsequently, the supernatant was incrassated by the decompression-drying method. Through colony forming unit assay, it was confirmed that L. plantarum had the function of growth inhibition to various bacteria. After culturing L. plantarum with bacterial media, the growth rate of L. plantarum was measured by absorbance (OD600), the results showed that the growth rate (E. coli treatment group: OD600 = 0.848, S. typhimurium treatment group: OD600 = 0.848) increased, as compared with the non-treated control group (OD600 = 0.48). In contrast, the concentrate itself did not induce the growth of L. plantarum. These results were observed as a universal phenomenon of the Lactobacillus species. Moreover, the increase in antimicrobial activity was observed in L. plantarum, which reacted with the culture media of E. coli and S. typhimurium, through a disc diffusion assay, and the result of growth inhibition against various bacteria was induced. Finally, based on the analysis results of the characteristics of bacteria culture media, which increased the growth rate of L. plantarum and antibacterial activity, the bacterial media had a tolerance for catabolic enzymes, pH 2­8 and heat. Therefore, this substance can be said to be a small molecule which is highly stable under various conditions.

Bacillus licheniformis 분리균 2종의 α-Galactosidase 생산성과 효소특성

진현경 ( Hyunkyung Jin ) , 윤기홍 ( Kihong Yoon )
4,500
초록보기
Two bacterial strains, Bacillus licheniformis YB-1413 and YB-1414, producing extracellular α-galactosidase, were obtained from homemade Doenjang. On the basis of their biochemical properties, 16S rRNA sequences and random amplified polymorphic DNA patterns by polymerase chain reaction, they were found to be somewhat different from one another. α-Galactosidase productivities of the two isolates were increased by wheat bran, but drastically decreased by melibiose, raffinose and sucrose which were used as carbon sources. The enzyme productivities were increased by yeast extract as a nitrogen source with maximum levels of 1.87 U/ml for YB-1413 and 1.69 U/ml for YB-1414, respectively. The enzymes of both isolates exhibited maximum activity for hydrolysis of para-nitrophenyl-α-D-galactopyranoside (pNP-αGal) under reaction conditions of pH 6.0 and 45oC. Their hydrolyzing activities for pNP-αGal were drastically decreased by the addition of low concentrations of ribose and galactose. They were capable of hydrolyzing completely α-1,6 linked galactosyl residue in melibiose, raffinose and stachyose, which are known to be anti-nutritional factors in products of soybean and legume. In relation to the latter, the isolates YB-1413 and YB-1414 have potential applicability in improving soybean-fermented foods and the nutritional value of soybean feed.
4,500
초록보기
A bacterial strain capable of hydrolyzing xylan and locust bean gum (LBG) was isolated from the Saemangeum tideland of Korea. Based on the biochemical properties and the 16S rRNA gene sequence, the isolate YB-30 was identified as Bacillus subtilis. Xylanase productivity was increased effectively when B. subtilis YB-30 was grown in the presence of wheat bran, while mannanase productivity was increased drastically when grown in the presence of konjac or LBG. Particularly, maximum mannanase and xylanase activities were detected in the culture filtrate of media containing 3.5% konjac and 1% wheat bran. Both enzyme productivities reached maximum levels in the stationary growth phase. The culture filtrate exhibited the highest activity at 60oC and pH 6.0 for mannanase and at 55oC and pH 5.5 for xylanase, respectively. Both enzymes were not stable at high temperatures and xylanase was less stable than mannanase. In addition, wheat bran was hydrolyzed to liberate reducing sugar to a greater extent than rice bran by the culture filtrate because the wheat bran contained more arabinoxylan than the rice bran. Hence, xylanase and mannanase produced by B. subtilis YB-30 have a potential use as feed additive enzymes.

Soluble Expression of the Fucosyltransferase Gene from Helicobacter pylori in Escherichia coli by Co-expression of Molecular Chaperones

( Areum Lee ) , ( Ling Li ) , ( Soyeon Shin ) , ( Jinseok Moon ) , ( Hyunju Eom ) , ( Namsoo Han )
4,500
초록보기
Fucosyltransferases (FucTs) catalyze fucosyl transfer from guanosine-diphosphate fucose (GDP-β-L-fucose) to acceptor molecules to form fucosyloligosaccharides with α-glycosidic linkages. However, when FucT genes have been expressed in Escherichia coli, most cases have resulted in the production of inclusion bodies. In this study, to overcome this drawback, molecular chaperones were co-expressed with α1,2-fucosyltransferase (FucT2) in E. coli. For this, the pACYC184 vector, having genes for chaperones such as GroEL, GroES, DnaK, DnaJ, and GrpE, were transformed into E. coli BL21 (DE3) star harboring pHFucT2, including the FucT2 gene from Helicobacter pylori 26695. The results from SDS-PAGE showed that 5 chaperones were successfully expressed and the soluble fraction of FucT2 was also increased. HPLC analysis revealed that the coexpression of chaperone proteins resulted in a 5-fold increase in the total activity of fucosyltransferase in E. coli. In conclusion, the FucT2 expression system developed in this study can be used as a useful tool for the synthesis of fucosyloligosaccharides.

Isolation and Characterization of Acetobacter Species from a Traditionally Prepared Vinegar

( Kang Wook Lee ) , ( Jaemin Shim ) , ( Gyeongmin Kim ) , ( Junghye Shin ) , ( Jeonghwan Kim )
4,500
초록보기
Acetic acid bacteria (AAB) were isolated from vinegar fermented through traditional methods in Namhae county, Gyeongnam, the Republic of Korea. The isolated strains were Gram negative, non-motile, and short-rods. Three selected strains were identified as either Acetobacter pasteurianus or Acetobacter aceti by 16S rRNA gene sequencing. A. pasteurianus NH2 and A. pasteurianus NH6 utilized ethanol, glycerol, D-fructose, D-glucose, D-mannitol, D-sorbitol, L-glutamic acid and Na-acetate. A. aceti NH12 utilized ethanol, n-propanol, glycerol, D-mannitol and Na-acetate. These strains grew best at 30oC and an initial pH of 3.4. They were tolerant against acetic acid at up to 3% of initial concentration (v/v). The optimum conditions for acetic acid production were 30oC and pH 3.4, with an initial ethanol concentration of 5%, resulting in an acetic acid concentration of 7.3­7.7%.

야생 효모 종류에 따른 알코올 발효 특성

백성열 ( Seongyeol Baek ) , 이유정 ( Youjung Lee ) , 김명동 ( Myoungdong Kim ) , 이재형 ( Jaehyoung Yi ) , 문지영 ( Jiyoung Mun ) , 여수환 ( Soohwan Yeo )
4,500
초록보기
The objective of this study was to improve the quality of Korean rice wine with wild type yeast strains isolated from various traditional Korean fermented foods. Herein the fermentation and sensory characterization of wild yeast, for the purposes of brewing Korean rice wine, was investigated. 12 yeast strains were examined for their ethanol and glucose tolerance. In addition, the pH, soluble solids, acidity, amino acidity, ethanol content, organic acids, and volatile compounds were also studied for the alcoholic beverages made with the wild yeasts. Almost all Saccharomyces genera yeasts were showed to have a tolerance at 10% ethanol, but non-Saccharomyces genera yeasts displayed a low tolerance. The alcoholic beverages fermented by non-Saccharomyces yeasts demonstrated higher levels of soluble solids, titratable acidity, amino acids, and lower ethanol content, when compared with the alcoholic beverages fermented by Saccharomyces genera yeasts. The organic acid content, such as malic acid, acetic acid, and succinic acid, was seen to also be higher. The electronic nose was analyzed, and discriminant function analysis (DFA) was used for discriminating wild yeast strains. The DFA plots indicated a significant separation of Saccharomyces genera and non-Saccharomyces yeast strains. For volatile compounds, ethyl acetate from non-Saccharomyces yeasts, and ethanol from Saccharomyces genera yeast, a high area ratio was observed.

Immobilization of the Hyperthermophilic Archaeon Thermococcus onnurineus Using Amine-coated Silica Material for H2 Production

( Seungseob Bae ) , ( Jeonggeol Na ) , ( Sungmok Lee ) , ( Sunggyun Kang ) , ( Hyunsook Lee ) , ( Junghyun Lee ) , ( Taewan Kim )
4,500
초록보기
Previously we reported that the hyperthermophilic archaeon, Thermococcus onnurineus NA1 is capable of producing hydrogen (H2) from formate, CO or starch. In this study, we describe the immobilization of T. onnurineus NA1 as an alternative means of H2 production. Amine-coated silica particles were effective in immobilizing T. onnurineus NA1 by electrostatic interaction, showing a maximum cell adsorption capacity of 71.7 mg-dried cells per g of particle. In three cycles of repeated-batch cultivation using sodium formate as the sole energy source, immobilized cells showed reproducible H2 production with a considerable increase in the initial production rate from 2.3 to 4.0 mmol l-1 h-1, mainly due to the increase in the immobilized cell concentration as the batch culture was repeated. Thus, the immobilized-cell system of T. onnurineus NA1 was demonstrated to be feasible for H2 production. This study is the first example of immobilized cells of hyperthermophilic archaea being used for the production of H2.

Candida tropicalis Isolated from Tuak, a North Sumatera-Indonesian Traditional Beverage, for Bioethanol Production

( Hermansyah ) , ( Novia ) , ( Minetaka Sugiyama ) , ( Satoshi Harashima )
4,500
초록보기
Tuak is a traditional alcoholic beverage, one of the most widely known in the North Sumateran region of Indonesia. It is produced by a spontaneous fermentation process through the application of one or more several kinds of wood bark or root, called raru (Xylocorpus wood bark or a variety of forest mangosteen), into the sap water of sugar palm (Arenga pinnata) for 2­3 days. In this research, yeast that are potentially useful for ethanol production was isolated from Tuak and identified. Based on analysis of D1/D2 domain sequence of LSU (large subunit) rRNA genes, those isolated yeast strains, HT4, HT5, and HT10 were identified as Candida tropicalis. Fermentation test of these C. tropicalis isolates displayed an ability to produce 6.55% (v/v) and 4.58% ethanol at 30oC and 42oC, respectively. These results indicated C. tropicalis isolates more rapidly utilize glucose and obtain higher levels of the production of ethanol at the higher temperature of 42oC than S. cerevisiae, a common yeast used for bioethanol fermentation.

Characteristics of Morphological and Physiological Changes during the Autolysis Process of Saccharomyces cerevisiae FX-2

( Xiao Li ) , ( Xiaodan Shi ) , ( Man Zou ) , ( Yudi Luo ) , ( Yali Tan ) , ( Yexu Wu ) , ( Lin Chen ) , ( Pei Li )
4,500
초록보기
In this paper, the autolysis process of Saccharomyces cerevisiae FX-2 (S. cerevisiae FX-2) via, a variety of endogenous enzyme, was investigated systematically by analyzing changes in physicochemical parameters in autolysate, surface morphology and the internal structure of the yeast cells. As an explicit conclusion, the arisen autolysis depended on the pH and the optimal pH was found to be 5.5. Based on the experimental data and the characteristics of mycelia morphology, a hypothesis is put forward that simple proteins in yeast vacuolar are firstly degraded for utilization, and then more membrane- bound proteins are hydrolyzed to release hydrolytic enzymes, which arouse an enzymatic reaction to induce the collapse of the cell wall into the cytoplasm.
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