• Title/Summary/Keyword: exopolysaccharide

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Diversity and Physiological Characteristics of Culturable Bacteria from Marine Sediments of Ross Sea, Antarctica (남극 로스해 퇴적물로부터 분리된 세균의 다양성 및 생리학적 특성)

  • Lee, Yung Mi;Jung, You-Jung;Hong, Soon Gyu;Kim, Ji Hee;Lee, Hong Kum
    • Korean Journal of Microbiology
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    • v.50 no.2
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    • pp.119-127
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    • 2014
  • The affiliations and physiological characteristics of culturable bacteria isolated from the sediments of Ross Sea, Antarctica were investigated. Sixty-three isolates obtained by cultivation were grouped into 21 phylotypes affiliated with the phyla Actinobacteria and Bacteroidetes and with the classes Alphaproteobacteria and Gammaproteobacteria by phylogenetic analysis of 16S rRNA gene sequences. Based on phylogenetic analysis (<98.65% sequence similarity), approximately 49% of total isolates represented potentially novel species or genus. Among them, extracellular protease, lipase, and exopolysaccharide activities at $10^{\circ}C$ or $20^{\circ}C$ were detected in approximately 46%, 25%, and 32% of the strains, respectively. Forty-three isolates produced at least one type of extracellular material and 21 of them produced at least two extracellular protease, lipase, and/or exopolysaccharides. Our findings indicate that culturable bacterial diversity present within the marine sediments of Ross Sea, Antarctica may contribute to the hydrolysis of the major organic constituents which is closely related with carbon and nitrogen cycling in this environment.

Biosorption of Cadmium by a Methanotrophs Exopolysaccharide (메탄산화세균의 EPS를 이용한 Cd의 생물흡착)

  • Lee, Hee-Ja;Kim, Kwang-Soo;Cho, Yang-Seok
    • Proceedings of the Korea Water Resources Association Conference
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    • 2006.05a
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    • pp.1415-1419
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    • 2006
  • 메탄을 탄소원 및 에너지원으로 이용하는 메탄산화균은 물질대사과정 중에 다량의 세포외 고분자물질인 Extracellular polymeric substances(EPS)를 생성하는데, EPS는 카르복실기와 같은 표면흡착 기능을 가지고 있어 생체흡착제로 사용이 가능하다. 따라서 본 연구에서는 메탄산화세균을 이용하여 중금속인 Cd의 흡착성능을 파악하여 활성슬러지의 흡착능과 비교하고, EPS 농도별, pH별 흡착량의 변화를 실험한 후 Freundlich 흡착모델식에 적용하여 흡착공정의 기본적인 설계인자를 도출하고자 하였다. 실험에 사용한 메탄산화세균은 매립지 복토층 상부 토양에서 분리하여 실험실에서 대량으로 배양하였으며, EPS 생성을 위해 메탄을 Head space의 20%를 주입하고 $30^{\circ}C$, 150rpm에서 질소원이 부족한 조건으로 48hr 동안 배양하였다. Cd의 흡착실험은 용액의 pH를 3에서 8까지 변화를 주면서 활성슬러지와 메탄산화세균의 시간별 흡착능을 측정하였다. 또한 중금속의 농도별 흡착능을 측정하여 흡착평형 상수를 파악하였으며, 중금속 흡착 전, 후 미생물의 SEM 촬영, FT-IR 분석, 전자현미분석(EPMA)을 통하여 무기성분 분석 및 표면관찰을 수행하였다. 실험결과 메탄산화세균에 의해 생성된 EPS 물질은 중금속에 대한 강한 결합능력이 있으며, Cd에 대한 최고 흡착능은 26mg Cd(Ⅱ)/g VSS의 값을 보였다. 이러한 미생물의 EPS의 흡착능은 pH와 칼슘이온의 영향을 많이 받았으며, 메탄산화세균의 FT-IR 분석결과 EPS에는 sulfate ester, pyruvate 등과 같은 작용기와 amino sugar, carboxyl 작용기들이 많이 존재하여 활성슬러지에 비해 중금속의 흡착능이 높은 것으로 사료되었다.X>${\mu}_{max,A}$는 최대암모니아 섭취률을 이용하여 구한 결과 $0.65d^{-1}$로 나타났다.EX>$60%{\sim}87%$가 수심 10m 이내에 분포하였고, 녹조강과 남조강이 우점하는 하절기에는 5m 이내에 주로 분포하였다. 취수탑 지점의 수심이 연중 $25{\sim}35m$를 유지하는 H호의 경우 간헐식 폭기장치를 가동하는 기간은 물론 그 외 기간에도 취수구의 심도를 표층 10m 이하로 유지 할 경우 전체 조류 유입량을 60% 이상 저감할 수 있을 것으로 조사되었다.심볼 및 색채 디자인 등의 작업이 수반되어야 하며, 이들을 고려한 인터넷용 GIS기본도를 신규 제작한다. 상습침수지구와 관련된 각종 GIS데이타와 각 기관이 보유하고 있는 공공정보 가운데 공간정보와 연계되어야 하는 자료를 인터넷 GIS를 이용하여 효율적으로 관리하기 위해서는 단계별 구축전략이 필요하다. 따라서 본 논문에서는 인터넷 GIS를 이용하여 상습침수구역관련 정보를 검색, 처리 및 분석할 수 있는 상습침수 구역 종합정보화 시스템을 구축토록 하였다.N, 항목에서 보 상류가 높게 나타났으나, 철거되지 않은 검전보나 안양대교보에 비해 그 차이가 크지 않은 것으로 나타났다.의 기상변화가 자발성 기흉 발생에 영향을 미친다고 추론할 수 있었다. 향후 본 연구에서 추론된 기상변화와 기흉 발생과의 인과관계를 확인하고 좀 더 구체화하기 위한 연구가 필요할 것이다.게 이루어질 수 있을 것으로 기대된다.는 초과수익률이 상승하지만, 이후로는 감소하므로, 반전거래전략을 활용하는 경우 주식투자기간은 24개월이하의 중단기가 적합함을 발견하였다. 이상의 행태적 측면과 투자성과측면의 실증결과를 통하여 한국주식시장에 있어서 시장수익률을 평균적으로 초과할 수 있는 거래전

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Effects of Microbacterium laevaniformans Levans Molecular Weight on Cytotoxicity

  • Oh, Im-Kyung;Yoo, Sang-Ho;Bae, In-Young;Cha, Jae-Ho;Lee, Hyeon-Gyu
    • Journal of Microbiology and Biotechnology
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    • v.14 no.5
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    • pp.985-990
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    • 2004
  • Levans produced from Microbacterium laevaniformans were isolated, characterized, and fractionated by molecular weight. TLC, HPLC, and GC-MS analyses of the exopolysaccharide showed that it was a fructan-type polymer and was composed of (2,6)- and (2,1)-glycosidic linkages. $^{13}C$-NMR analysis proved that the polysaccharide was mainly a $\beta$-(2,6)-linked levan-type polysaccharide. To investigate the cytotoxicity of the acetone-precipitated levan fractions such as M1, M2, and M3, HepG2, P388D1, U937, SNU-1, and SNUC2A cell lines were screened. Among the cell lines tested, the cytotoxicity of M1- M3 fractions were detected from only SNU-1 and HepG2 cells at the dosage level of $100-800\mu\textrm{g}ml$. The M2 fraction M_r$, 80,000) at 400 $mu{g/ml}$ had the greatest cell growth inhibition (84.6%) on SNU-1, while the M1 $(M_r$, 50,000) at $800\mu\textrm{g}ml$ showed the greatest (46.32%) on HepG2. To obtain more uniform M_r$ fractions of levan, the levan was further fractionated from S1 $(M_r$ 1,000,000) to S5 $(M_r$ 10,000) using gel permeation chromatography. Again, the S1-S5 fractions had strong cytotoxicity on SNU-1 and HepG2 cell lines. The greatest inhibition effects of S4 $(M_r$ 80,000) on SNU-1 and S5 $(M_r$ 10,000) on HepG2 were shown to be 49.5% and 73.0%, respectively. The cytotoxicity of the levan fractions was more effective on SNU-1 than on HepG2. Although the relationship between the Mw and the cytotoxicity was not clear, smaller $M_r$, fractions of levan showed greater growth inhibition effect on the cancer cell lines in general. Therefore, it was indicated that a specific Mw class of levan is responsible for the effective cytotoxicity.

Streptococcus thermophilus K-1 및 Lactobacillus acidophilus LB12 균주에 있어 최대 Exopolysaccharide 생산에 영향을 미치는 물리적 원인 규명을 위한 연구

  • 강현미;엄양섭;정충일
    • Proceedings of the Korean Society of Food Hygiene and Safety Conference
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    • 1999.10a
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    • pp.119-119
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    • 1999
  • EPS를 생성하는 Str. thermophilus K-1 및 Lb. acidophilus LB12를 10% 환원 탈지유에 배양하고, EPS 생산을 위한 배지로는 Elliker broth를 사용하여 20, 25 및 $37^{\circ}C$에서 72시간까지 저장하면서 12시간 간격으로 시료를 꺼내어 EPS생산량, 생균수, 산도 및 점도 등을 측정하여 EPS생산과 이들 물리저 요인들과의 상호관계를 조사하였다. Str. thermophilus K-1의 경우, $20^{\circ}C,\;37^{\circ}C$에 저장한 시료의 EPS 생산량은저장 60시간에 각각 0.358, 0.386O.D.로 최대를 나타내었으며, 저장 72시간에는 다소 감소하는 것으로 나타났다. $25^{\circ}C$에 저장한 시료는 저장 36시간부터 O.D. 0.313으로 급속히 증가하여 72시간까지 그 수준을 거의 유지하는 것으로 나타났다. Lb. acidophilus CH-2의 경우에는 25, $37^{\circ}C$에서는 EPS생산이 서서히 증가하다가, 36, 48시간에 0.775, 0.833O.D.로 각각 최대를 나타낸 후에 다시 서서히 감소하는 것으로 나타났으며, 저장 $20^{\circ}C$에서는 저장 60시간에 1.123O.D.로 EPS생산이 최대에 도달한 후 저장 72시간에는 다시 감소하는 것으로 나타났다. 이 두균주의 세 가지 배양 온도에서 EPS가 최대를 나타내는 시점은 생균수가 감소하는 시점과 일치하므로, 균주 및 배양온도에 상관없이 균성장 말기 또는 균사멸기 초기에 EPS가 가장 많이 생산됨을 알 수 있었다. 또한 점도 및 산도는 저장 온도가 높을수록, 그리고 저장 기간이 길어질수록 대체로 많이 생성되는 것으로 나타났으며, EPS생산과의 유의성도 상당히 높은 것으로 나타났다. 것들이 부딛힘이 없이 공존하고 일상의 논리가 무시된다. 부정, 의심이 없고 확실한 것이 없다. 한 대상에 가졌던 생각이 다른 대상에 옮겨간다(displacement). 한 대상이 여러 대상이 갖고 있는 의미를 함축하고 있다(condensation). 시각적인 순서가 무시된다. 마음속의 생각과 외부의 실제적인 일을 구분하지 못한다. 시간 상의 순서가 있다가 없다가 한다. 차례로 일어나야 할 일이 동시에 한꺼번에 일어난다. 대상들이 서로 비슷해지고 동시에 있을 수 없는 대상들이 함께 나타난다. 사고의 정상적인 구조가 와해된다. Matte-Blance는 무의식에서는 여러 독립된 대상들간의 구분을 없애며, 주체와 객체를 하나로 보려는 대칭화(symmetrization)의 경향이 있기 때문에 이런 변화가 생긴다고 하였다. 또 대칭화가 진행되면 무한대의 느낌을 갖게 되어, 전지(moniscience), 전능(omnipotence), 무력감(impotence), 이상화(idealization)가 나타난다. 그러나 무의식에 대칭화만 있는 것은 아니며, 의식의 사고양식인 비대칭도 어느 정도 나타나며, 대칭화의 정도에 따라, 대상들이 잘 구분되어 있는 단계, 의식수준의 감정단계, 집단 내에서의 대칭화 단계, 집단간에서의 대칭화 단계, 구분이 없어지는 단계로 구분하였다.systems. We believe that this taxonomy is a significant contribution because it adds clarity, completeness, and "global perspective" to workflow architectural discussions. The vocabulary suggested here includes workflow levels and aspects, allowing very different architectures to be discussed,

Isolation and Characterization of Dextrans Produced by Leuconostoc sp. strain JYY4 from Fermented Kimchi

  • Gu, Ji-Joong;Ha, Yoo-Jin;Yoo, Sun-Kyun
    • Journal of the Korean Applied Science and Technology
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    • v.32 no.4
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    • pp.758-766
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    • 2015
  • Dextran is a generic term for a bacterial exopolysaccharide synthesized from sucrose and composed of chains of D-glucose units connected by ${\alpha}$-1,6-linkages by using dextransucrases. Dextran could be used as vicosifying, stabilizing, emulsifying, gelling, bulking, dietary fiber, prebiotics, and water holding agents. We isolated new strain capable of producing dextran from Korean traditional kimchi and identified as Leuconostoc sp. strain JYY4. Batch fermentation was conducted in bioreactor with a working volume of 3 L. The media was MMY and 15% (w/v) sucrose. Mineral medium consisted of $3.0g\;KH_2PO_4$, $0.01g\;FeSO_4$, $H_2O$, $0.01g\;MnSO_4$, $4H_2O$, $0.2g\;MgSO_4\;7H_2O$, 0.01 g NaCl, $0.05g\;CaCl_2$ per 1 liter deionized water. The pH of media was initially adjusted to 6.0. The inoculation rate was 1.0% (v/v) of the working volume. Temperature was maintained at $28^{\circ}C$. The agitation rate was 100 rpm. The production pattern of dextran was associated with the cell growth. After 24 hr dextran reached its highest concentration of 59.4 g/L. The sucrose was consumed completely after 40 hr. Growth reached stationery phase when sucrose became limiting, regardless of the presence of fructose or mannitol. When the specific growth rate was 0.54 hr-1, utilization averaged 5.8 g/L-hr. The yield and productivity of dextran were 80% and 2.0 g/L-hr, respectively. Dextrans produced by were separated to two different size by an alcohol fraction method. The size of high molecular weight dextran (45% alcohol, v/v), less soluble dextran, was between MW 500,000 and 2,000,000. Soluble dextran (55% alcohol, v/v) was between 70,000 and 150,000. The molecular weight average of total dextran (70% alcohol, v/v) was between 150,000 to 500,000. The enzymatic hydrolyzates of total dextran of ATCC 13146 showed branched dextrans by Penicillium dextranase contained of glucose, isomaltose, isomaltotriose, and isomaltooligosaccharides greater than DP4 (degree of polymerization) that had branch points. Compounds greater than DP4 were branched isomaltooligosaacharides. Hydrolysates by the Lipomyces dextranase produced the same composition of oligosaccharides as those by Penicillin dextranase.

Production of Mycelia and Water Soluble Polysaccharides from Submerged Culture of Ganoderma applanatum Using Different Types of Bioreactor (생물반응기 유형에 따른 잔나비불로초(Ganoderma applanatum)의 균사체 및 수용성 다당체 생산 특성)

  • Lee, Wi-Young;Park, Young-Ki;Ahn, Jin-Kwon;Park, So-Young
    • The Korean Journal of Mycology
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    • v.34 no.1
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    • pp.1-6
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    • 2006
  • In order to select a suitable bioreactor type for the submerged cultivation of Ganoderma applanatum, both growth characteristics and polysaccharides production were compared among four different types of bioreactor. These include an external-loop type air-lift bioreactor (ETAB), a balloon type air bubble bioreactor (BTBB), a column type air bubble bioreactor (CTBB) and a stirrer type bioreactor (STB). The mycelial biomass produced from the reactors were in decreasing order: ETAB ($7\;g/{\ell}$) > BTBB ($6.2\;g/{\ell}$) > STB ($6\;g/{\ell}$) > CTBB ($5\;g/{\ell}$). Maximal soluble exopolysaccharides ($1\;g/{\ell}$) and endopolysaccharides (2.7%) were also obtained from ETAB. Thus, the ETAB was most suitable for submerged culture of G applanatum mycelium. Based on the results, ETAB was chosen for further detailed study. The most effective aeration rate for the mycelial growth in ETAB ranged from 0.05 to 0.1 vvm. For the maximal production, the mycelium at the initial growth stage needed low aeration rate to reduce cell damages by fluid flow. However, as the mycelia grew, the culture became viscous and thus needed higher aeration. The molecular weight of exopolysaccharides obtained from the culture grown in ETAB was higher than that from the culture grown in other bioreactors.

Anti-Inflammatory Activity of Liquid Fermentation by Phellinus linteus Mycelium (상황버섯(Phellinus linteus) 균사체 액체발효물의 항염증 활성)

  • Shin, Hyun Young;Kim, Hoon;Jeong, Eun-Jin;Kim, Hyun-Gyeong;Son, Seung-U;Suh, Min Geun;Kim, Na Ri;Suh, Hyung Joo;Yu, Kwang-Won
    • The Korean Journal of Food And Nutrition
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    • v.34 no.5
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    • pp.487-497
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    • 2021
  • To investigate the industrial availability of liquid fermentation (PL-ferment) by Phellinus linteus mycelium as a postbiotics for the inhibition of inflammation, PL-ferment was fractionated into culture supernatant (CS), hot-water extract (HW) from PL-ferment, EtOH-precipitate (CP) fractionated from HW, and the dialysate (DCP) of CP. Compared to the other fractions, DCP which is expected to contain exopolysaccharide (EPS) as the major component, significantly decreased the production of NO, IL-6, and MCP-1 in LPS-induced RAW 264.7 cells, and IL-6 and IL-8 in TNF-α and IFN-γ-induced HaCaT cells. The general component analysis results showed that no significant difference in components was observed between the fractions, whereas sugar composition analysis revealed that DCP had decreased glucose and increased mannose contents compared to the other fractions. This suggests that mannose played an important role in the anti-inflammatory activity of the active fraction, DCP. Molecular weight distribution analysis revealed that DCP was mainly composed of low-molecular-weight material-removed high-molecular-weight polysaccharides of 18-638 kDa, suggesting that EPS originated from P. linteus EPS. In conclusion, our results suggest that the DCP of P. linteus mycelium fermentation using the anti-inflammatory activity could be used industrially as postbiotic material.

Screening of Bacterial Strains for Alleviating Drought Stress in Chili Pepper Plants (고추 식물의 건조 스트레스 완화를 위한 미생물 선발)

  • Kim, Sang Tae;Yoo, Sung-Je;Song, Jaekyeong;Weon, Hang-Yeon;Sang, Mee Kyung
    • Research in Plant Disease
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    • v.25 no.3
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    • pp.136-142
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    • 2019
  • Drought stress is considered as one of major abiotic stresses; it leads to reduce plant growth and crop productivity. In this study, we selected bacterial strains for alleviating drought stress in chili pepper plants. As drought-tolerant bacteria, 28 among 447 strains were pre-selected by in vitro assays including growth in drought condition with polyethylene glycol and plant growth-promoting traits including production of 1-aminocyclopropane-1-carboxylate deaminase, indole-3-acetic acid and exopolysaccharide. Sequentially, 7 among pre-selected 28 strains were screened based on relative water content (RWC); GLC02 and KJ40, among seven strains were finally selected by RWC and malondialdehyde (MDA) in planta trials under an artificial drought condition by polyethylene glycol solution. Two strains GLC02 and KJ40 reduced drought stress in a natural drought condition as well as an artificial condition. Strains GLC02 or KJ40 increased shoot fresh weight, chlorophyll and stomatal conductance while they decreased MDA in chili pepper plants under a natural drought condition. However, two strains did not show biocontrol activity against diseases caused by Phytophthora capsici and Xanthomonas campestris pv. vesicatoria in chili pepper plants. Taken together, strains GLC02 or KJ40 can be used as bio-fertilizer for alleviation of drought stress in chili pepper plants.

Characterization of exopolysaccharide-producing lactic acid bacteria from Taiwanese ropy fermented milk and their application in low-fat fermented milk

  • Ng, Ker-Sin;Chang, Yu-Chun;Chen, Yen-Po;Lo, Ya-Hsuan;Wang, Sheng-Yao;Chen, Ming-Ju
    • Animal Bioscience
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    • v.35 no.2
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    • pp.281-289
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    • 2022
  • Objective: The aim of this study was to characterize the exopolysaccharides (EPS)-producing lactic acid bacteria from Taiwanese ropy fermented milk (TRFM) for developing a clean label low-fat fermented milk. Methods: Potential isolates from TRFM were selected based on the Gram staining test and observation of turbid suspension in the culture broth. Random amplified polymorphic DNA-polymerase chain reaction, 16S rRNA gene sequencing, and API CHL 50 test were used for strain identification. After evaluation of EPS concentration, target strains were introduced to low-fat milk fermentation for 24 h. Fermentation characters were checked: pH value, acidity, viable count, syneresis, and viscosity. Sensory evaluation of fermented products was carried out by 30 volunteers, while the storage test was performed for 21 days at 4℃. Results: Two EPS-producing strains (APL15 and APL16) were isolated from TRFM and identified as Lactococcus (Lc.) lactis subsp. cremoris. Their EPS concentrations in glucose and lactose media were higher than other published strains of Lc. lactis subsp. cremoris. Low-fat fermented milk separately prepared with APL15 and APL16 reached pH 4.3 and acidity 0.8% with a viable count of 9 log colony-forming units/mL. The physical properties of both products were superior to the control yogurt, showing significant improvements in syneresis and viscosity (p<0.05). Our low-fat products had appropriate sensory scores in appearance and texture according to sensory evaluation. Although decreasing viable cells of strains during the 21-day storage test, low-fat fermented milk made by APL15 exhibited stable physicochemical properties, including pH value, acidity, syneresis and sufficient viable cells throughout the storage period. Conclusion: This study demonstrated that Lc. lactis subsp. cremoris APL15 isolated from TRFM had good fermentation abilities to produce low-fat fermented milk. These data indicate that EPS-producing lactic acid bacteria have great potential to act as natural food stabilizers for low-fat fermented milk.

Sigma S Involved in Bacterial Survival of Ralstonia pseudosolanacearum (Ralstonia pseudosolanacearum 생존에 관여하는 Sigma S 역할)

  • Hye Kyung Choi;Eun Jeong Jo;Jee Eun Heo;Hyun Gi Kong;Seon-Woo Lee
    • Research in Plant Disease
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    • v.30 no.2
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    • pp.148-156
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    • 2024
  • Ralstonia pseudosolanacearum, a plant pathogenic bacterium that can survive for a long time in soil and water, causes lethal wilt in the Solanaceae family. Sigma S is a part of the RNA polymerase complex, which regulates gene expression during bacterial stress response or stationary phase. In this study, we investigated the role of sigma S in R. pseudosolanacearum under stress conditions using a rpoS-defective mutant strain of R. pseudosolanacearum and its wild-type strain. The phenotypes of rpoS-defective mutant were complemented by introducing the original rpoS gene. There were no differences observed in bacterial growth rate and exopolysaccharide production between the wild-type strain and the rpoS mutant. However, the wild-type strain responded more sensitively to nutrient deficiency compared to the mutant strain. Under the nutrient deficiency, the rpoS mutant maintained a high bacterial viability for a longer period, while the viability of the wild-type strain declined rapidly. Furthermore, a significant difference in pH was observed between the culture supernatant of the wild-type strain and the mutant strain. The pH of the culture supernatant for the wild-type strain decreased rapidly during bacterial growth, leading to medium acidification. The rapid decline in the wild-type strain's viability may be associated with medium acidification and bacterial sensitivity to acidity during transition to the stationary phase. Interestingly, the rpoS mutant strain cannot utilize acetic acid, D-alanine, D-trehalose, and L-histidine. These results suggest that sigma S of R. pseudosolanacearum regulates the production or utilization of organic acids and controls cell death during stationary phase under nutrient deficiency.