• 한국축산식품학회지
• /
• 제27권4호
• /
• pp.538-542
• /
• 2007

본 연구는 kefir로부터 EPS를 분리하여 MA104 세포에 대한 독성과 rotavirus에 대한 저해효과를 확인하기 위하여 수행하였다. Kefir culture 및 grain 파쇄입자에서 Lactobacillus fermentum, Lactobacillus acidophilus, Lactobacillus brevis 등의 유산균과 Candida kefyr, Cryptococcus albidus, Pichia ohmeri 등의 효모가 분리 동정되었다. EPS의 1% 농도에서, MTT assay에 의한 EPS의 rotavirus에 대한 억제효과는 human rotavirus(KU)가 $72.52{\pm}6.48%$, bovine rotavirus(NCDV)가 $36.06{\pm}7.63%$, porcine rotavirus(OSU)가 $81.66{\pm}1.11%$로 나타났으며, EPS의 1/128% 농도에서, human rotavirus(KU)가 $24.98{\pm}4.58%$, bovine rotavirus(NCDV)가 $4.71{\pm}6.16%$, porcine rotavirus(OSU)가 $4.05{\pm}14.90%$로 나타났다. Kefir에서 분리한 EPS는 다양한 혈청형과 유래 동물의 rotavirus 모두에게 억제 효과가 있는 것으로 확인되었다.

• The Plant Pathology Journal
• /
• 제35권2호
• /
• pp.178-187
• /
• 2019

Plants are exposed to biotic stresses caused by pathogen attack and complex abiotic stresses including heat and drought by dynamic climate changes. To alleviate these stresses, we investigated two bacterial stains, H26-2 and H30-3 in two cultivars ('Ryeokkwang' and 'Buram-3-ho') of Chinese cabbage in plastic pots in a greenhouse. We evaluated effects of bacterial strains on plant growth-promotion and mitigation of heat and drought stresses; the role of exopolysaccharides as one of bacterial determinants on alleviating stresses; biocontrol activity against soft rot caused by Pectobacterium carotovorum subsp. carotovorum PCC21. Strains H26-2 and H30-3 significantly increased fresh weights compared to a $MgSO_4$ solution; reduced leaf wilting and promoted recovery after re-watering under heat and drought stresses. Chinese cabbages treated with H26-2 and H30-3 increased leaf abscisic acid (ABA) content and reduced stomatal opening after stresses treatments, in addition, these strains stably colonized and maintained their populations in rhizosphere during heat and drought stresses. As well as tested bacterial cells, exopolysaccharides (EPS) of H30-3 could be one of bacterial determinants for alleviation of tested stresses in Chinese cabbages, however, the effects were different to cultivars of Chinese cabbages. In addition to bacterial activity to abiotic stresses, H30-3 could suppress incidence (%) of soft rot in 'Buram-3-ho'. The tested strains were identified as Bacillus aryabhattai H26-2 and B. siamensis H30-3 based on 16S rRNA gene sequence analysis. Taken together, H26-2 and H30-3 could be candidates for both plant growth promotion and mitigation of heat and drought stresses in Chinese cabbage.

• Journal of Microbiology and Biotechnology
• /
• 제31권11호
• /
• pp.1545-1551
• /
• 2021

Exopolysaccharides (EPSs) such as capsular polysaccharide (CPS) are important bioactive carbohydrate compounds and are often used as bioenrichment agents and bioabsorbers to remove environmental pollutants like di-n-butyl phthalate (DBP). Among the EPS-producing bacteria, lactic acid bacteria (LAB) have gained the most attention. As generally recognized as safe (GRAS) microorganisms, LAB can produce EPSs having many different structures and no health risks. However, EPS production by LAB does not meet the needs of large-scale application on an industrial scale. Here, the capA gene (encoding CPS biosynthesis protein) was overexpressed in Lactobacillus plantarum P1 to improve the production of EPSs and further enhance the DBP adsorption capability. Compared with P1, the CPS production in capA overexpressed strain was increased by 11.3 mg/l, and the EPS thickness was increased from 0.0786 ± 0.0224 ㎛ in P1 to 0.1160 ± 0.0480 ㎛ in P1-capA. These increases caused the DBP adsorption ratio of P1-capA to be doubled. Overall, the findings in this study provide a safe method for the adsorption and removal of DBP.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2000년도 봄 학술발표회 논문집
• /
• pp.331-337
• /
• 2000

When microorganism is injected into porous medium such as soils, biomass retained in the pore. Bacteria within these microcolonies produced large amounts of exopolysaccharides and formed a plugging biofilm. Soil pore size and shape are varied from the initial condition as a result of biofilm formation, which make hydraulic conductivity reduced and friction rate between soil aggregates increased. In this research, hydraulic conductivity reduction was measured after microorganism are inoculated and cultured with synthetic substrate and nutrient. Also, pore sand of before and after biofilm formation compared with scanning electron microscopy. Hydraulic conductivity of Sand and Poorly Graded Sand was decreased approximately 1/10∼1/100 after biomass inoculation and cultivation. Biofilm attached on soil aggregates is resistant to acidic or basic condition.

• KSBB Journal
• /
• 제11권1호
• /
• pp.115-123
• /
• 1996

zooglan생합성에 필수적인 gene cluster를 clone하기 위해 2종류의 변이주가 분리되었다. Zoogloea ramigera 115는 협막형 다당(주로 zooglan)을 생산한다. 115 균주로 접합시키고 생산물을 용이하게 분리하기 위하여 반복된 원심분리와 선별을 통해 협막을 만들지 않는 slime형 생산균주를 분리하였다. 세포외 다당 생산 능력이 결여된 변이주를 전통적인 transposon(Tn5) 기술을 사용하여 얻었고 달라진 colony 형태와 celluflour결합 성질에 의해 선별하였다. 이들 변이주들은 범용숙주범위 cosmid vector안에 건설된 Z.ramigera 115slime gene library 와 helper plasmid로의 3양친 접합에 의해 보상되었다.

• 미생물학회지
• /
• 제50권2호
• /
• pp.119-127
• /
• 2014

남극 로스해의 퇴적물로부터 배양을 통해 분리한 균주의 분류 및 생리학적 특성 분석을 수행하였다. 분리 세균 63균주의 16S rRNA 유전자 염기서열을 이용한 계통분류학적 분석 결과, 이들은 Actinobacteria, Bacteroidetes, Alphaproteobacteria 및 Gammaproteobacteria 내의 21개의 파일로타입(phylotypes)에 속하였다. 98.65% 염기서열 유사도를 기준으로, 약 49%의 균주가 잠재적으로 신종 또는 신속 후보인 것으로 나타났다. 분리된 균주 중, 각각 46%, 25% 및 32%의 균주가 세포외 단백질분해효소, 지질분해효소 및 외부다당체 생성에 대한 활성을 나타냈다. 43개의 균주는 최소 1개의 세포외 분비 물질을 생산하였고, 이들 중 21개 균주는 최소 2개의 세포외 단백질분해효소, 지질분해효소 또는/및 세포외다당체를 생성하였다. 이러한 결과는 남극 로스해 퇴적물 내의 배양된 세균 군집이 해당 환경에서 탄소와 질소와 관련된 유기물질의 가수분해에 영향을 미치고 있다는 것을 시사한다.

• 한국균학회지
• /
• 제34권1호
• /
• pp.1-6
• /
• 2006

잔나비불로초 배양에 적합한 생물반응기를 선발하기 위하여 4종류의 생물반응기 형태별 균사체 생장특성과 다당체 생산량을 비교하였다. 균사체 생산량은 기포통기형 생물반응기($7\;g/{\ell}$) > 풍선형 생물반응기($6.2\;g/{\ell}$) > 교반형 생물반응기($6\;g/{\ell}$) > 컬럼형 생물반응기($5\;g/{\ell}$) 순으로 나타났으며, 기포통기형 생물반응기에서 가장 높은 세포외 다당체($1\;g/{\ell}$)와 세포 내다당체(2.7%)를 생산하여 기포통기형 생물반응기가 잔나비불로초 균사체 배양에 가장 적합한 것으로 나타났다. 세포외 다당체의 분자량도 생물반응기의 형태별에 따라 다르게 나타났으며, 기포통기형 생물반응기에서 가장 높은 분자량을 나타냈다. 기포통기형 생물반응기에서의 적정한 공기공급율은 0.05부터 0.1 vvm 사이로 나타났다. 특히 잔나비불로초 균사체는 배양하면서 배지의 점도가 높아져 점차 공기 공급량을 높여 주는 것이 좋은 것으로 판단된다.

• KSBB Journal
• /
• 제19권6호
• /
• pp.457-461
• /
• 2004

본 연구에서는 A. blazei의 DO-스탯 현탁 유가식 배양을 통하여 균사체 및 세포외 다당체 생산을 극대화하고자 하였다. 탄소원만을 포함하는 기질 공급액을 사용하는 경우보다 질소원이 적절히 첨가된 혼합 기질 공급액을 사용하는 것이 균사체 및 세포외 다당체 생산에 보다 효과적이었다. 기질공급액 중의 탄소원 조성을 달리하여 실험을 수행한 결과, 덱스트린을 배제하고 포도당만을 탄소원으로 사용하였을 때 가장 높은 균사체 및 세포외 다당체 생산성을 얻을 수 있었다. 이 때의 균사체 농도 및 생산성은 각각 36.5 g/l, 0.37g/l-h이었으며, 세포외 다당체 농도 및 생산성은 각각 10.9 g/l, 0.11 g/l-h이었다. 이는 회분식 배양 결과와 비교하여 균사체 농도 및 생산성 면에서는 각각 6배 및 2.2배, 세포외 다당체 농도 및 생산성 면에서는 각각 4.7배 및 1.8배 증가한 값이다. 이상의 결과들로부터 A. blazei의 고농도 균사체 배양을 위해 유가식 배양 방법이 매우 효과적임을 알 수 있었다.

• Animal Bioscience
• /
• 제35권2호
• /
• pp.281-289
• /
• 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.

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2000년도 춘계학술발표대회
• /
• pp.137-140
• /
• 2000

Marine microorganism strain 96CJ10356 produced exopolysaccharides, designated as EPS-R. To optimize culture conditions for the production of EPS-R, carbon, nitrogen, mineral salt, temperature, and pH were examined. STN medium was suggested as follow; sucrose 20, tryptone 10, NaCl 10, $MgSO_4$ 5, $CaCl_2$ 1, $KH_2PO_4$ 0.0076, $K_2HPO_4$ 0.0083, $FeCl_2$ 0.005, $MnCl_2$ 0.001, $NaMoO_4$ 0.001, $ZnCl_2$ 0.001 (g/1) and pH 7.0 About 9.23 g/l of EPS-R was obtained from the STN medium after cultivation for 120 h at $25^{\circ}C$ in 5-liter jar fermentor with an aeration rate of 0.17 vvm. Apparent viscosity and flocculation activity of the culture broth were increased with the production of the EPS-R and the maximal values were reached to 415 cp and 1400 units/ml against 0.5 % activated carbon, respectively.