• 산업기술연구
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• 제24권B호
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• pp.171-176
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• 2004

The effects of agitation and aeration for exopolysaccharide(EPS) production through batch cultivation of an Enterobacter sp. isolated from the composter were investigated. During the EPS fermentation under conditions of constant agitation speed from 200 to 900 rpm and constant aeration rate of 0.5-2.5 vvm, the low yields of EPS(4.8-5.2g/L) was observed as the viscosity increase of culture broth. With the stepwise increases in agitation speed and aeration rate, the EPS production and the viscosity of EPS were increased 1.3~1.4 times and 2.3~3.6 times higher than those of the fixed conditions, respectively. Therefore, these stepwise increases were considered as the key operating parameters for enhancing EPS production. The max. EPS(6.8g/L) and viscosity(14,000cp) were obtained when the agitation speed was increased from 300 to 900 rpm for 54hrs at 1.5 vvm.

• KSBB Journal
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• 제23권1호
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• pp.18-22
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• 2008

EPS 생산량이 다양한 환경 인자 요소에 의해 달라진다는 것이 여러 연구를 통해 알려졌다(1, 5, 10, 11). 본 연구에서는 환경인자를 다음과 같은 요소 (온도, 탄소원, pH, 질소원과 탄소원)로 변화시켜 보면서 관찰하였다. 다양한 환경인자 중 EPS 생산량에 가장 큰 영향을 준 요소는 온도였다. 온도를 $37^{\circ}C$에서 $25^{\circ}C$로 낮추었을 때 EPS 생산량은 2배 이상 증가하는 것을 관찰할 수 있었다(Fig. 3(A)). 탄소원으로 galactose를 사용했을 때 EPS 생산이 가장 효율적이었으나(Fig. 2(A)), 수율 면에서는 lactose를 이용했을 때 가장 효과적이었다(Fig. 2(B)). 그러나 lactose를 사용했을 때 L. paracasei KLB 58의 성장이 매우 저조하였다. 이에 대한 균체량을 증가시킬 수 있는 방법을 모색한다면, EPS 생산하는데 있어 lactose가 휼륭한 탄소원으로 사용될 가능성이 있다고 여겨진다. 반면에, 질소원의 양을 증가시켰을 때의 EPS 생산량의 증가는 거의 변함이 없었다. 5가지 환경요소 (온도, 탄소원, pH, 질소원과 탄소원)를 변화시켜본 인자 중 질소원의 양을 변화시켰을 때 EPS 변화가 가장 적었고, 탄소원의 증가는 EPS 생산의 증가를 가져왔다.

• Journal of Microbiology and Biotechnology
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• 제10권3호
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• pp.381-385
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• 2000

The effect and interaction of Ca and B on exopolysaccharide (EPS) synthesis in the diazotrophically growing cyanobacterium. Nostoc spongiaeforme, was investigated. The absence of B inhibited EPS synthesis 1.56-fold ($16\mu\textrm{g}$ glucose equivalent/mg dry weight, 16 d) over the control cells ($25\mu\textrm{g}$ glucose equivalent) grown in medium containing 0.5 mM Ca and $8{\mu}{\textrm}{m}$ B. When B concentration was raised to $40{\mu}{\textrm}{m}$, EPS production was stimulated 1.8-fold. Reduction of Ca concentraion to one-half (0.25 mM) resulted in increased B demand (16$\muM$) by the cells for EPS production at par with the normal sets. However, without Ca, EPS production also increased as B increased. Addition of B to a Ca-free medium stimulated cyanobacterial diazotrophic growth as well as synthesis of Chl a and phycocyanin (0-8 d). The data suggest B-dependent diazotrophic growth during Ca-deficiency and point to and important interactive role of Ca and B in regulation of cyanobacterial EPS synthesis.

• Food Science and Biotechnology
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• 제17권3호
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• pp.587-593
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• 2008

Microbial exopolysaccharide (EPS) is a biothickener that can be added to a wide variety of food products, where it serves as a viscosifying, stabilizing, emulsifying, and gelling agent. The objective of this study was to investigate the optimum conditions of pH, incubation temperature, and whey protein concentration (WPC) for EPS production by Lactobacillus rhamnosus ATCC 9595. We found that maximal EPS production was achieved at a pH of 5.5 and temperature of $37^{\circ}C$. At the same fermentation conditions, EPS production was affected by the addition of L. rhamnosus GG (a weak-EPS producer). After growth for 24 hr, total EPS production was $583{\pm}15.4mg/L$ in the single culture system, and $865{\pm}22.6\;mg/L$ in the co-culture system with L. rhamnosus GG. Based on the presence of WPC, EPS production dramatically increased from $583{\pm}15.4$ (under no WPC supplementation) to $1,011{\pm}14.7\;mg/L$ (under supplementation with 1.0% WPC). These results suggest that WPC supplementation and the co-culture systems coupled with small portions of weak-EPS producing strain can play an important role in the enhancement of EPS production.

• Journal of Microbiology and Biotechnology
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• 제17권1호
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• pp.44-51
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• 2007

Marine bacterial strains were isolated trom coastal regions of Goa and screened for the strains that produce the highest amount of mucous expolysaccharide (EPS). Our screening resulted in the identification of the strain Vibrio furnissii VB0S3 (hereafter called VB0S3), as it produced the highest EPS in batch cultures during the late logarithmic growth phase. The isolate was identified as VB0S3 based on morphological and biochemical properties. Growth and EPS production were studied in mineral salts medium supplemented with NaCl (1.5%) and glucose (0.2%). The exopolymer was recovered from the culture supernatant by using three volumes of cold ethanol precipitation and dialysis procedure. Chemical analyses of EPS revealed that it is primarily composed of neutral sugars, uronic acids, and proteins. Fourier-transform infrared (FT-IR) spectroscopy revealed the presence of carboxyl, hydroxyl, and amide groups, which correspond to a typical heteropolymeric polysaccharide, and the EPS also possessed good emulsification activity. The gas chromatographic analysis of an alditol-acetate derivatized sample of EPS revealed that it was mainly composed of galactose and glucose. Minor components found were mannose, rhamnose, fucose, ribose, arabinose, and xylose. EPS was readily isolated from culture supernatants, which suggests that the EPS was a slime-like exopolysaccharide. This is the first report of exopolysaccharide characterization that describes the isolation and characterization of an EPS expressed by Vibrio surnissii strain VB0S3. The results of the study contribute significantly and go a long way towards an understanding of the correlation between growth and EPS production, chemical composition, and industrial applications of the exopolysaccharide in environmental biotechnology and bioremediation.

• Biotechnology and Bioprocess Engineering:BBE
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• 제5권3호
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• pp.181-185
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• 2000

A marine microorganism, strain 96CJ10356 produced exopolysaccharide, designated as EPS-R. To optimize culmize culture conditions for the production of EPS-R, carbon and nitrogen sources, mineral salts, temperature, and pH were exmined. From this study, STN medium for the production of EPS-R was suggested as follows; sucrose 20g, typtone 10g, NaCl 10g, MgSO45g, CaCl21g, KH2PO4 76mg, K2HPO4 83mg, FeCl2 5mg, MnCl2 1mg, NaMoO4 1mg, and ZnCl2 1mg per liter at pH 7.0. About 9.23g/L of EPS-R was obtained from STN medium after cultivation for 120h at $25^{\circ}C$ in a 5-liter jar fermentor with an aearation rate of 0.17 vvm. Apparent viscosity and flocculation activity of the culture broth were increased with the production of EPS-R and the maximal values were 415 cP and 1400 unit/mL against 0.5% activated carbon, respectively.

• KSBB Journal
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• 제17권2호
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• pp.169-175
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• 2002

원유로부터 다당류를 생산하는 유산균을 분리, 선발하여 균의 배양조건을 조사하고 Lactobacillus ssp. SCU-M으로 동정, 명명된 최적배지의 탄소원은 galactose 1.5% 첨가시 553 mg/L의 EPS를 생성하였으며 whey의 이용성 검토를 위한 deproteinized whey와 lactic acidified whey를 탄소원으로 사용하였을 때 각각 639, 550 mg/L를 생성하였다. 질소원으로 yeast extract 1.5%, peptone 0.5%를 첨가한 경우 934 mg/L, 미량성분으로 , 0.15% $K_2$HPO, 0.15% 첨가시 1,076 mg/L의 다당 생산성을 나타내었다. 따라서 이들 결과를 종합하여 galactose 1.50%, yeast extract 1.00%, peptone 0.25%, MgSO$_4$, 7$H_2O$ 0.15%, $K_2$HPO$_4$0.15%, tween 80, 0.10%를 적정 배지로 하여 PH 6.5, 배양온도 37$^{\circ}C$에서 배양시 1,680 mg/L의 EPS를 생성하였다.

• 한국미생물·생명공학회지
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• 제30권3호
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• pp.264-269
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• 2002

Zoogloea ramigera l15SLR로부터 zooglan다당류의 생산을 위한 최적조건에 관한 연구를 수행하였다 탄소원으로 2.5%의 glucose와 lactose를 이용하였을 때 각각 10.7, 10.5 g/L의 다당류를 생산하였으며 , galactose, white sugar, brown sugar의 경우는 각각 6.4, 6.7, 8.7 g/L의 다당류 생산 을 보였다. 2.5% glucose가 첨가된 제한배지에서 종균 배양액(TSB 배지)을 7ml 이상 접종함으로서 종균 1 ml를 접종 하석 생산된 다당류(2.37 gt) 보다 약 4배의 높은 다당류 생산(10.28 g/L)을 보였다. 종균 배양액을 5 ml이상 접종시에 배양 36시간 이후부터 다당류를 생산하였으며 48시간 배양시에 10g/L이상의 다당류 생산이 가능하였다. 탄소원으로서 또한, 종균 배양액의 흡광도가 1.0~l.7일 경우에 10g/L 이상의 다당류를 생산하였으며, 이 범위를 벗어나는 경우에는 다당류 생산이 저해되었다. 배양액에 rifampicin첨가는 12 g/L이상의 다당류 생산을 보였으며, 다당류 분자량은 1.367$\times$106(g/mol)로서 rifampicin을 가하지 경우 1.711$\times$106(g/mol)와 약간의 차이를 보였다.

• The Plant Pathology Journal
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• 제39권5호
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• pp.417-429
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• 2023

Ralstonia solanacearum species complex (RSSC) is a soil borne plant pathogen causing bacterial wilt on various important crops, including Solanaceae plants. The bacterial pathogens within the RSSC produce exopolysaccharide (EPS), a highly complicated nitrogencontaining heteropolymeric polysaccharide, as a major virulence factor. However, the biosynthetic pathway of the EPS in the RSSC has not been fully characterized. To identify genes in EPS production beyond the EPS biosynthetic gene operon, we selected the EPS-defective mutants of R. pseudosolanacearum strain SL341 from Tn5-inserted mutant pool. Among several EPSdefective mutants, we identified a mutant, SL341P4, with a Tn5-insertion in a gene encoding a putative NDP-sugar epimerase, a putative membrane protein with sugar-modifying moiety, in a reverse orientation to EPS biosynthesis gene cluster. This protein showed similar to other NDP-sugar epimerases involved in EPS biosynthesis in many phytopathogens. Mutation of the NDP-sugar epimerase gene reduced EPS production and biofilm formation in R. pseudosolanacearum. Additionally, the SL341P4 mutant exhibited reduced disease severity and incidence of bacterial wilt in tomato plants compared to the wild-type SL341 without alteration of bacterial multiplication. These results indicate that the NDP-sugar epimerase gene is required for EPS production and bacterial virulence in R. pseudosolanacearum.

• 한국미생물·생명공학회지
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• 제46권1호
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• pp.9-17
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• 2018

The aims of this work were to characterize and determine bioactivities of crude exopolysaccharide (EPS) extract from Bacillus tequilensis PS21 isolated from milk kefir from Kampaeng Petch, Thailand. B. tequilensis PS21 produced 112.1 mg dried EPS/l from initial 80 g/l lactose in modified TSB media at 52 h, with EPS product yield of 8.9 mg EPS/g lactose and specific product yield of 0.3 mg EPS/mg biomass. The FTIR result confirmed EPS to be a protein-bound polysaccharide and SEM analysis showed the morphology to be a grainy appearance with an uneven surface, covered with pores. HPLC analysis determined EPS as a heteropolysaccharide consisting of five sugar units with the following molar ratios; xylose (17.65), glucose (2.54), ribose (1.83), rhamnose (1.23), and galactose (1). Chemical components of this EPS were predominantly carbohydrate at 697.8 mg/g EPS (65%), protein 361.4 mg/g EPS (34%), and nucleic acid 12.5 mg/g EPS (1%). The EPS demonstrated antioxidant activities at 57.5% DPPH scavenging activity, $37.2{\mu}M\;Fe(II)/mg$ EPS and $34.9{\mu}M\;TEAC\;{\mu}M/mg$ EPS using DPPH, FRAP and ABTS assays, respectively. EPS also exhibited anti-tyrosinase activity at 34.9% inhibition. This work represents the first finding of EPS produced by Bacillus sp. from Thai milk kefir which shows potential applications in the production of antioxidant functional foods and whitening cosmetics. However, optimization of EPS production for industrial exploitation requires further study to ascertain the economic potential.