• Journal of Microbiology
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• v.45 no.6
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• pp.510-514
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• 2007

Twenty-five bacterial strains that secrete mucous materials were isolated from sediment obtained from King George Island, Antarctica. Seven of these strains proved capable of producing cryoprotective exopolysaccharides. The strain KOPRI 21653 was selected for the further study of an anti-ice-nucleating polysaccharide (ANP), which originated from a polar region. KOPRI 21653 was identified as Pseudoalteromonas arctica as the result of 16S rRNA analysis. The exopolysaccharide, P-21653, was purified completely from the KOPRI 21653 cell culture via column chromatography and protease treatment. The principal sugar components of P-21653 were determined to be galactose and glucose, at a ratio of 1:1.5, via GC-MS analysis. The cryoprotective activity of P-21653 was characterized via an E. coli viability test. In the presence of 0.1% (w/v) P-21653, the survival ratio of E. coli cells was as high as 82.6% over three repeated freeze-thaw cycles. The survival ratio decreased drastically to 71.5 and 48.1 %, respectively, in five and seven repeated cycle conditions; however, the survival ratios were greater over three (96.6-92.1%) to seven (100.5-91.6%) freeze-thaw cycles in the presence of 0.5 and 1.0% (w/v) P-21653. In addition, at much lower concentrations (0.1-1.0%), P-21653 resulted in survival ratios (83.1-98.4%) similar to those of two commercially available cryoprotectants ($V_{EG}$ plus X-1000, 92.9% and $V_{M3}$, 95.3%), which were utilized at the recommended concentrations (90%). The biochemical characteristics of exopolysaccharide P-21653 reflect that this compound may be developed as a useful cryoprotectant for use in medical applications and in the food industry.

• Food Science and Biotechnology
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• v.17 no.3
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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 Industrial Technology
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• v.25 no.B
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• pp.241-251
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• 2005

Exopolysaccharide (CBP) from submerged culture broth of Ganoderma lucidum mycelium and the water soluble (BWS) and water insoluble (BWI) fractions of CBP were prepared by gel filtration. Antitumor activity and effects on proliferation and differenciation of human cancer cells and mouse NIH 3T3 cells were studied. Cytotoxicity test of CBP, BWS and BWI fractions on human cancer cell lines was performed by using sulforhodamine B (SRB) assay. A549 (lung carcinoma), Colo320 DM and HSR (colon carcinoma), and NIH 3T3 cells were used. BWI fraction showed the strongest cytotoxicity (maximum 20% survival) to all human cells tested. However it did not induced apoptosis. Interestingly BWI fraction did not exert cytotoxic effect on NIH 3T3 cells at low concentration of cells ($5{\times}10^4$) but strong toxic effect at high concentration of cells($5{\times}10^5$) which showed transformed morphology. These results suggest that BWI may have cancer cell specific anticancer activity. However, BWI fraction did not effect the amount of pRb and c-myc protein, which implied that BWI fraction did not act at the early stage of signal transduction pathway. CBP fraction induced differenciation of human leukemic cell line, HL-60 cells suggesting the carcinogenesis prevention of normal cell and possible induction of normalization for cancer cell.

• Microbiology and Biotechnology Letters
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• v.46 no.1
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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.

• Journal of Microbiology and Biotechnology
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• v.23 no.5
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• pp.681-688
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• 2013

This work is aimed to increase knowledge of the functional exopolysaccharide (EPS) from lactic acid bacteria (LAB) in makgeolli, a Korean fermented rice wine. Among LAB strains isolated from makgeolli, strain M76 was selected as a functional strain producing a bioactive EPS, based on its antioxidative activity on the DPPH radical. The 16S rRNA gene sequencing analysis showed a high sequence similarity (99.0%) with P. acidilactici, but had different biochemical properties with the already known P. acidilactici type strains in the aspect of carbohydrates utilization. The obtained P. acidilactici M76 produced a soluble EPS above 2 g/l. One-step chromatography using gel filtration after ethanol precipitation from the supernatant of P. acidilactici M76 was enough to obtain purified EPS with a single peak, showing a molecular mass of approximately 67 kDa. Componential and structural analyses of EPS by TLC, HPLC, and FT-IR indicated that the EPS is a glucan, consisting of glucose units. The purified EPS had antioxidant activity on the DPPH radical of 45.8% at a concentration of 1 mg/ml. The purified EPS also showed proliferative effect on the pancreatic RIN-m5F cell line and remarkable protection activity on alloxan-induced cytotoxicity. This potent antioxidant and antidiabetic EPS by LAB in makgeolli may contribute to understanding the functionality of makgeolli.

• Microbiology and Biotechnology Letters
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• v.30 no.3
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• pp.264-269
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• 2002

The production of exopolysaccharide from Zoogloea ramigera 115SLR in batch culture was affected by carbon sources, rifampicin concentration, inoculum size and cell density of starter culture. The increase of organic nitrogen concentration and cell density in defined medium by adding starter culture resulted in higher production of exopolysaccharide (EPS) within 2 days. Glucose and lactose as carbon sources showed EPS production of 10.7 gk and 10.5 ga, respectively. Higher EPS production was obtained with 2.5% (w/v) glucose. White sugar, brown sugar and galactose produced less than 10 gt of EPS. The optical density of starter culture affected on EPS yield, producing over 10 gt of EPS in the range of 1.0-1.7. In the presence of rifsmpicin, Z. ramigera 115SLR produced EPS of 12.9 gt. Molecular weight of EPS produced with/without rifampicin was determined with 1.367$\times$106 and 1.711$\times$106 g/mol using HPSEC-MALLS-RI, respectively.

• Biomedical Science Letters
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• v.6 no.1
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• pp.1-9
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• 2000

To identity the genes responsible for the biosynthesis of exopolysaccharide, recombinant plasmids pUEX10 and pLEX10 were constructed from plasmid pLEX3 which was isolated from the recombinant cosmid library of Zoogloea ramigera 115. The complete nucleotide sequence of the 1.7 kb genomic DNA insert in plasmid pUEX10 was determined. Its analysis identified two open reading frames (ORF3 & ORF4) which could encode two proteins. The amino acid sequence derived from ORF3 showed the homology with gumC protein in Xanthomonas campestris as well as exoP protein in Rhizobium melizoti. The partial amino acid sequence of ORF4 showed the homology with polysaccharide export protein in Thermotoga maritima. Z. ramigera 115SLR and Z. ramigera 115SLR/pLEX10 showed the similar pattern for EPS production. Yield of exopolysaccharides produced by Z. ramigera 115SLR and Z. ramigera 115SLR/pLEX10 was 0.26% (w/v) and 0.16% (w/v), respectively.

• Journal of Microbiology and Biotechnology
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• v.18 no.1
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• pp.67-73
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• 2008

The potential of the exopolysaccharide (EPS) from a Serratia sp. strain Gsm01 as an antiviral agent against a yellow strain of Cucumber mosaic virus (CMV-Y) was evaluated in tobacco plants (Nicotiana tabacum cv. Xanthi-nc). The spray treatment of plants using an EPS preparation, 72h before CMV-Y inoculation, protected them against symptom appearance. Fifteen days after challenge inoculation with CMV-Y, 33.33% of plants showed mosaic symptoms in EPS-treated plants compared with 100% in the control plants. The EPS-treated plants, which showed mosaic symptoms, appeared three days later than the controls. The enzyme-linked immunosorbent assay (ELISA) and reverse transcriptase polymerase chain reaction (RT-PCR) analyses of the leaves of the protected plants revealed that the EPS treatment affected virus accumulation in those plants. Analysis of phenylalanine ammonia lyase, peroxidase, and phenols in protected plants revealed enhanced accumulation of these substances. The pathogenesis-related (PR) genes expression represented by PR-lb was increased in EPS-treated plants. This is the first report of a systemic induction of protection triggered by EPS produced by Serratia sp. against CMV-Y.

• Journal of Microbiology and Biotechnology
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• v.28 no.8
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• pp.1282-1292
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• 2018

The exopolysaccharide (EPS) produced by Bacillus amyloliquefaciens GSBa-1 was isolated and purified by ethanol precipitation, and DEAE-cellulose and Sepharose CL-6B chromatographies. The molecular mass of the purified EPS was determined to be 54 kDa. Monosaccharide analysis showed that the EPS was composed of predominantly glucose, and it was further confirmed by NMR spectroscopy to be ${\alpha}-glucan$ that consisted of a trisaccharide repeating unit with possible presence of two ${\alpha}-(1{\rightarrow}3)$ and one ${\alpha}-(1{\rightarrow}6)$ glucosidic linkages. Microstructural analysis showed that the EPS appeared as ellipsoid or globose with a smooth surface. The EPS had a degradation temperature at $240^{\circ}C$. Furthermore, the EPS had strong DPPH and hydroxyl radical scavenging activities, and moderate superoxidant anion scavenging and metal ion-chelating activities. This is the first characterization of a glucan produced by B. amyloliquefaciens with strong antioxidant activity. The results of this study suggest the potential of the EPS from B. amyloliquefaciens GSBa-1 to serve as a natural antioxidant for application in functional products.

• KSBB Journal
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• v.23 no.1
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• pp.18-22
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• 2008

Various probiotic Lactobacillus spp. are known to produce exopolysaccharide (EPS) which has potential health promoting functionality. A Lactobacillus paracasei strain producing EPS was isolated from healthy human. This strain, named L. paracasei KLB58, was grown on modified MRS medium. Experiments were conducted under various growth conditions to optimize the EPS production. Our study showed that incubation temperature played an important role in EPS production. When incubation temperature was changed from $37^{\circ}C$ to $25^{\circ}C$, the increase of EPS production (28.1 mg/ml) was the highest in our experiment. The type of carbon source in the medium also affected EPS production. Galactose was the most effective for EPS production among the carbon sources examined. Using galactose, glucose, lactose and sucrose, the amount of released EPS was 38.9 mg/ml, 35.6 mg/ml, 21.76 mg/ml and 16.9 mg/ml, respectively. However, acidity in growth medium inhibited EPS productivity due to the low growth yield. When grown at pH 4, L. paracasei KLB58 could only produce EPS of 14.6 mg/ml. When the initial amounts of nitrogen and carbon sources were examined, EPS production was not significantly affected by nitrogen source while carbon source affected considerably.