• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.615-620
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• 2003

The sulfated exopolysaccharide p-KG03, which is produced by the marine microalga Gyrodinium impudicum strain KG03, exhibited impressive antiviral activity in vitro ($EC_{50}$ = 26.9 g/ml) against the encephalomyocarditis virus (EMCV). Depending on the p-KG03 concentration, the development of cytopathic effects in EMCV-infected HeLa cells was either inhibited completely or slowed. Moreover, p-KG03 did not show any cytotoxic effects on HeLa cells, even at concentrations up to 1,000 g/ml. The polysaccharide was purified by repeated precipitation in ethanol, followed by gel filtration. The p-KG03 polysaccharide had a molecular weight of $1.87\;{\times}\;10^6$, and was characterized as a homopolysaccharide of galactose with uronic acid (2.96%, w/w) and sulfate groups (10.32% w/w). The biological activities of p-KG03 suggest that sulfated metabolites from marine organisms are a rich source of antiviral agents. This is the first reported marine source of antiviral sulfated polysaccharides against EMCV. The p-KG03 polysaccharide may be useful for the development of marine bioactive exopolysaccharides for use in biotechnological and pharmaceutical products.

• Journal of Dairy Science and Biotechnology
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• v.35 no.3
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• pp.196-201
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• 2017

Recent studies have reported that certain lactic acid bacteria and their metabolites, such as exopolysaccharides (EPSs), have immunological effects and can modulate the immune system following oral administration. Lactococcus lactis subsp. cremoris FC is a lactic acid bacteria isolated from fermented milk from Caucasians and has been shown to produce EPSs. In this study, the effects of lactoferrins (apo-lactoferrin, holo-lactoferrin, and native-lactoferrin) and transferrins (apo-transferrin and holo-lactoferrin) on the growth of L. lactis subsp. cremoris FC were examined. The addition of lactoferrins and transferrins to L. lactis subsp. cremoris FC cultures was found to be effective at concentrations of 0.5 or 1 mg/mL.

• Food Science of Animal Resources
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• v.38 no.5
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• pp.1008-1018
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• 2018

Although bacteriocins with anti-listerial activity have been isolated from a wide variety of lactic acid bacteria, little is known about those from Leuconostoc lactis, a heterofermentative bacterium that produces diacetyl and exopolysaccharides in dairy foods. In this study, an anti-listerial bacteriocin was isolated from Leuc. lactis SD501 and characterized. It was particularly potent against Listeria monocytogenes and also inhibited Enterococcus faecalis. Anti-listerial activity reached a maximum during the early stationary phase and then decreased gradually. The anti-listerial substance was sensitive to proteinase K and ${\alpha}$-chymotrypsin, confirming its proteinaceous nature. Its activity remained stable at pH values ranging from 1 to 10. In addition, it was strongly resistant to high temperatures, retaining its activity even after incubation for 15 min at $121^{\circ}C$. The apparent molecular mass of the partially purified anti-listerial bacteriocin was approximately 7 kDa. The characteristics of the SD501 bacteriocin, including its small molecular size (<10 kDa), strong anti-listerial activity, wide pH stability and good thermostability, indicate its classification as a Class IIa bacteriocin.

• Journal of Microbiology and Biotechnology
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• v.4 no.3
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• pp.195-199
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• 1994

Immunostimulation effects of the cell wall components isolated from Lactobacillus plantarum were investigated by studying the macrophage s tumorcidal activity, splenocyte proliferation, anticomplementary activity and the inhibition of peritoneal tumor cell growth measured with ICR mice inoculated with sarcoma 180. The immunopotentiating cell wall components were a complex of peptidoglycan and exopolysaccharides. The tumorcidal activity of macrophage against Yacl and B16 tumor cells was enhanced when the cell wall components were added into the macrophage s culture medium. They also stimulated splenocytes to proliferate up to the same level as when the concanavalin A was added into the splenocyte's culture medium. The complementary activity was inhibited by 50% when the cell wall components were incubated with the sheep red blood cells treated with hemolysin and guinea pig complement. This result confirmed that the cell wall components had an antitumor effect, because the anticomplementary activity is usually accompanied by an antitumor activity at the same time. This fact was confirmed again by the inhibition of the growth of sarcoma 180 when the cell wall components were injected intraperitoneally into ICR mice inoculated with sarcoma 180. As a result, it is concluded that the cell wall components isolated from Lactobacillus plantarum had multifunctional immunostimulation effects in vitro and in vivo.

• Journal of Dairy Science and Biotechnology
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• v.24 no.1
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• pp.65-73
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• 2006

This study was to review recent reports in effects of various starter cultures on the viscosity in stirred yogurt. The rheological properties of yogurt have received considerable attention in the literature. Most yogurts are typically made by mixed cultures of Lactobacillus bulgaricus and Streptococcus thermophilus. The viscosity of yogurt made by mixed cultures was much higher than that of yogurt by single cultures. Since texture of stirred yogurt is the result of both acid aggregation of casein micelles and production of exopoly-saccharides, it is suggested that yogurt be made by the exopolysaccharide-producing cultures in order to increase viscosity, Both types of exopolysaccharides are capsule and loose slime(ropy). But it is desirable to use encapsulated nonropy strains. And Bifidobacteria affects adversely to the viscosity of yogurt. Therefore, starter cultures which have an effect on yogurt viscosity have been widely demonstrated. This review is the search for the development of viscosity in stirred yogurt.

• Journal of Microbiology and Biotechnology
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• v.17 no.6
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• pp.979-984
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• 2007

The physicochemical properties of the exopolysaccharide (EPS) produced by marine bacterium Zoogloea sp. KCCM10036 were investigated. Two types of isolated EPSs were shown to have average relative molecular masses $(M_r)\;of\;4.07{\times}10^6$ of CBP (cell-bound polysaccharide) and $3.43{\times}10^6$ of WSP (water-soluble polysaccharide), respectively. When the CBP was utilized as an emulsifier, it stabilized the emulsifier, for up to 148 h. Compared with other commercially available hydrocolloids such as xanthan gum, the Tween series, and Triton, the CBP showed much better emulsifying capability on a water-in-oil system. Phase separation occurred in the Tween series after 24 h, whereas the emulsion was better stabilized by the CBP. The CBP thus has potential as an emulsifying agent in commercial emulsions. The flocculating activity was also greatest at 0.01% (w/v) and decreased at higher concentrations than the optimized concentration of the WSP and CBP. The results also showed that both types of expolysaccharides from Zoogloea sp. had excellent flocculating activity.

• Journal of Microbiology and Biotechnology
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• v.20 no.1
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• pp.161-168
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• 2010

In this study, the metabolic activities of five strains of Pediococcus spp., in terms of the quantities they produced of lactic acid, hydrogen peroxide, exopolysaccharides, and proteolytic activity, were determined. Lactic acid levels produced by these strains were found to be in the range of 2.5-5.6 mg/ml. All strains produced hydrogen peroxide. The P. pentosaceus Z13P strain produced the maximum amount (0.25 mg/ml) of proteolytic activity. Exopolysaccharide (EPS) production by the Pediococcus strains during growth in MRS (de Man, Rogosa, and Sharpe) medium was in the range 25-64 mg/l. The susceptibility of 10 different antibiotics against these strains was also tested. All strains were found to be resistant to amoxicillin, gentamicin, and vancomycin. Antimicrobial effects of the Pediococcus spp. on pathogens were also determined by an agar diffusion method. All of the strains were able to inhibit L. monocytogenes. The tolerance of the strains to low pH, their resistance to bile salts of strains, and their abilities to autoaggregate and coaggregate with L. monocytogenes were also evaluated.

• Journal of Microbiology and Biotechnology
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• v.16 no.6
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• pp.939-945
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• 2006

The physiological characteristics and function of the exopolysaccharide (EPS) produced by Lactobacillus rhamnosus ATCC 9595 were determined. The total quantity of EPS was rapidly increased to 496$\pm$20 mg/l during the exponential phase, and then maintained steadily during the stationary phase. During the exponential phase (18 h), the total EPS consisted of 61% cell-bound EPS (cb-EPS) and 39% released EPS (r-EPS), whereas the relative proportion of EPS during the stationary phase (48 h) was convered to 23% cb-EPS and 77% r-EPS. On gel permeation chromatography, cb-EPS was fractionated as a single peak of 8.6$\times10^6$ Da, whereas r-EPS was fractionated as two peaks with average molecular weights of 4.3$\times$10$^4$ and 8.6$\times10^6$ Da. Interestingly, both EPS species exhibited anticancer properties and cholera toxin-binding activities. Our results suggest that the EPS generated by L. rhamnosus ATCC 9595 might be suitable for use as a functional food or food supplement.

• Microbiology and Biotechnology Letters
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• v.46 no.2
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• pp.91-101
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• 2018

The aim of this study was to transfer the 18.5 kb gene clusters coding for 17 genes from Lactobacillus rhamnosus to Lactococcus lactis subsp. cremoris MG1363 in order to determine the effect of host on exopolysaccharide (EPS) production and to provide a model for studying the phosphorylation of proteins which are proposed to be involved in EPS polymerization. Lactobacillus rhamnosus RW-9595M and ATCC 9595 have 99% identical operons coding for EPS biosynthesis, produced different amounts of EPS (543 vs 108 mg/l). L. lactis subsp. cremoris MG1363 transformed with the operons from RW-9595M and ATCC 9595 respectively, produced 326 and 302 mg/l EPS in M17 containing 0.5% glucose. The tyrosine protein kinase transmembrane modulator (Wzd) was proposed to participate in regulating chain elongation of EPS polymers by interacting with the tyrosine protein kinase Wze. While Wzd was found in phosphorylated form in the presence of the phosphorylated kinase (Wze), no phosphorylated proteins were detected when all nine tyrosines of Wzd were mutated to phenylalanine. Lactococcus lactis subsp. cremoris could produce higher amounts of EPS than other EPS-producing lactococci when expressing genes from L. rhamnosus. Phosphorylated Wzd was essential for the phosphorylation of Wze when expressed in vivo.

• Preventive Nutrition and Food Science
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• v.21 no.2
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• pp.117-123
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• 2016

Bioconversion of aglycone-formed isoflavones from glycoside-formed isoflavones by commercial lactic acid bacteria in fermented soybean paste was evaluated. Enterococcus faecium KCTC 13410 showed the most resistant capacity and Lactobacillus acidophilus KCTC 3925 had a sensitive susceptibility at a high NaCl concentration (13.2%) in fermented soybean paste. Among the 5 strains tested, Lac. acidophilus KCTC 3925 showed the highest relative ratio of aglycone-formed isoflavones to total isoflavones in fermented soybean paste. Production of exopolysaccarides (EPS) by lactic acid bacteria was compared using de Man, Rogosa, and Sharpe medium containing 1% sucrose at $37^{\circ}C$ for 48 h. Among the 5 lactic acid bacteria, Lac. acidophilus KCTC 3925 and Lactobacillus rhamnosus KCTC 3929 were investigated to produce EPS. Based on the results concerning growing susceptibility and conversion of aglycone-formed isoflavones/EPS production, it is anticipated that Lac. acidophilus KCTC 3925 may be used for preparation of Cheonggukjang, which contains relative low NaCl content.