• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.2
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• pp.338-342
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• 2002

Antimicrobial activity of yellow pigment produced by Monascus anka Y7 (Y7) was studied. The crude yellow pigment of Y7 showed antimicrobial activity against some bacteria and yeasts. The diameter of inhibition zone against gram-positive bacteria was a little smaller t]fan that of gram-negative bacteria to the crude yellow pigment. Especially, E2 fraction obtained from the crude yellow pigment by TLC method showed high anti-microbial activity against E. coli.. The fraction had bright yellow pigment, showing fluorescent light and having the maximum absorption at 373 nm. Citrinin, a mycotoxin which had been characterized as an antimicrobial substance from a Monascus strain, was not detected in the E2 fraction and in the crude yellow pigment by the results of TLC and HPLC. This indicates that the antimicrobial activity of Y7 pigments did not any relationship with citrinin. Yellow degree (b/a of Hunters color value) of Y7 pigment was much higher than that of other natural colorants such as annatto, gardenia yellow and carthamus yellow. But the colors of all of the yellow pigments were similar by panels. Thus, the yellow pigment of Y7 could be used as a useful alternative colorant for food industry, having the advantage of antimicrobial activity.

• KSBB Journal
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• v.19 no.2
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• pp.148-153
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• 2004

Lipase catalyzes the hydrolysis of glycerides into fatty acids and glycerol. The study of microbial lipases has been stimulated in resent years. It is due to the potential uses of lipases in esterification of oils to glycerol, alcohols and carbohydrates. Development of lipase producing yeast has been focused concerning to the utilization of yeast culture for animal feed. In this study, yeast like cells was isolated from a waste oil and sludge. A strain having higher lipase activity was selected by random mutagenesis using UV-radiation. The optimal cultivation conditions in submerged culture were examined in terms of lipase production. 2.0％ of high fructose syrup, 1,0％ of CSL, and 1.0％ of olive oil were selected as the nutritional media for the production of lipase. The maximum lipase activity of 1.12 U/ml and viable cell number of 8.8${\times}$10$\^$7/ cells/mL were obtained at 27$^{\circ}C$ with an initial pH of 5.0.

• Food Science and Preservation
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• v.10 no.2
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• pp.224-229
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• 2003

This study was carried out to isolate of antagonistic bacterium to Allium cepa L. pathogens. A total of 250 strains were isolated from A. cepa L. roots. The isolates were screened for antagonism to A. cepa L. pathogens and the isolated strain No. YJ-4 was selected among these bacteria. It was identified as Bacillus ehimensis based on morphological and physiological characteristics according to the Bergey's mannual of systematic bacteriology, Sherlock system of Microbial ID Int and 165 rDNA sequences methods. Bacillus ehimensis YJ-4 showed broad spectrum of antibacterial and antifungal activities against plant pathogens as Alternaria porri, Botrytis cinerea, Erwinia carotovora subsp. carotovora Fusarium of oxysporium, penicillium sp., Pseudomonas sp., Rhizoctonia solani, Sclerotium cepivotum, Septoria sp., Stemphylium botryosum. Speially B. ehimensis YJ-4 showed high antifungal activity on growth against F. oxysporium, the causal agent of onion Fusarium wilt.

• Journal of Microbiology and Biotechnology
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• v.21 no.11
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• pp.1174-1178
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• 2011

Exopolysaccharides (EPSs) are microbial polysaccharides that are released outside of the bacterial cell wall. There have been few studies on EPS-producing lactic acid bacteria that can enhance macrophage activity and the underlying signaling mechanism for cytokine expression. In the current study, EPS-overproducing Lactobacillus (L.) paracasei KB28 was isolated from kimchi and cultivated in conditioned media containing glucose, sucrose, and lactose. The whole bacterial cells were obtained with their EPS being attached, and the cytokine-inducing activities of these cells were investigated. Gas chromatography analysis showed the presence of glucose, galactose, mannose, xylose, arabinose, and rhamnose in EPS composition. EPS-producing L. paracasei KB28 induced the expression of tumor necrosis factor (TNF)-${\alpha}$, interleukin (IL)-6, and IL-12 in mouse macrophages. This strain also caused the degradation of $I{\kappa}B{\alpha}$ and phosphorylation of the major MAPKs: Jun N-terminal kinase (JNK), p38, and extracellular signal-regulated kinase (ERK)1/2. The use of pharmacological inhibitors showed that different signaling pathways were involved in the induction of TNF-${\alpha}$, IL-6 and IL-12 by L. paracasei KB28. Our results provide information for a better understanding of the molecular mechanisms of the immunomodulatory effect of food-derived EPS-producing lactic acid bacteria.

• Journal of Microbiology and Biotechnology
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• v.22 no.7
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• pp.1015-1020
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• 2012

Antifungal cement mortar or microbiological calcium carbonate precipitation on cement surface has been investigated as functional concrete research. However, these research concepts have never been fused with each other. In this study, we introduced the antifungal calcite-forming bacteria (CFB) Bacillus aryabhattai KNUC205, isolated from an urban tunnel (Daegu, South Korea). The major fungal deteriogens in urban tunnel, Cladosporium sphaerospermum KNUC253, was used as a sensitive fungal strain. B. aryabhattai KNUC205 showed $CaCO_3$ precipitation on B4 medium. Cracked cement mortar pastes were made and neutralized by modified methods. Subsequently, the mixture of B. aryabhattai KNUC205, conidiospore of C. sphaerospermum KNUC253, and B4 agar was applied to cement cracks and incubated at $18^{\circ}C$ for 16 days. B. aryabhattai KNUC205 showed fungal growth inhibition against C. sphaerospermum. Furthermore, B. aryabhattai KNUC205 showed crack remediation ability and water permeability reduction of cement mortar pastes. Taken together, these results suggest that the $CaCO_3$ precipitation and antifungal properties of B. aryabhattai KNUC205 could be used as an effective sealing or coating material that can also prevent deteriorative fungal growth. This study is the first application and evaluation research that incorporates calcite formation with antifungal capabilities of microorganisms for an environment-friendly and more effective protection of cement materials. In this research, the conception of microbial construction materials was expanded.

• Korean Journal of Environmental Agriculture
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• v.30 no.3
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• pp.346-356
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• 2011

BACKGROUND: Chemical fungicides not only may pollute the ecosystem but also can be environmentally hazardous, as the chemicals accumulate in soil. Biological control is a frequently-used environment-friendly alternative to chemical pesticides in phytopathogen management. However, the use of microbial products as fungicides has limitations. This study isolated and characterized a three-antifungal-enzyme (chitinase, cellulase, and ${\beta}$-1,3-glucanase)-producing bacterium, and examined the conditions required to optimize the production of the antifungal enzymes. METHOD AND RESULTS: The antifungal enzymes chitinase, cellulase, and ${\beta}$-1,3-glucanase were produced by bacteria isolated from an sawmill in Korea. Based on the 16S ribosomal DNA sequence analysis, the bacterial strain AM50 was identical to Streptomyces sp. And their antifungal activity was optimized when Streptomyces sp. AM50 was grown aerobically in a medium composed of 0.4% chitin, 0.4% starch, 0.2% ammonium sulfate, 0.11% $Na_2HPO_4$, 0.07% $KH_2PO_4$, 0.0001% $MgSO_4$, and 0.0001% $MnSO_4$ at $30^{\circ}C$. A culture broth of Streptomyces sp. AM50 showed antifungal activity towards the hyphae of plant pathogenic fungi, including hyphae swelling and lysis in P. capsici, factors that may contribute to its suppression of plant pathogenic fungi. CONCLUSION(S): This study demonstrated the multiantifungal enzyme production by Streptomyces sp. AM50 for the biological control of major plant pathogens. Further studies will investigate the synergistic effect, to the growth regulations by biogenic amines and antifungal enzyme gene promoter.

• Korean Journal of Microbiology
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• v.36 no.3
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• pp.209-215
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• 2000

The purpose of U7is work was to iilvestigate the degradation of s-h~azine hel-hicidcs, ahilzine and simazine by TNT-degrader under several relevaut physicochemical environ~nental parameters. TNT-degrader showed effective degradability of atrazine and snnazine as well. Both atrazme (GO 1i1~11) and simazine ( 4 5 rng//) were completely degraded within 30 hrs and 4 days of incubation, respectively. As d ~ e concentrations of atrazine and sunazine increased in the media, the degradation ofthose compounds were delayed. Additional caubans were essential to degrade atrazine and simazule, and no degradation was achieved in the absence of additional carbons. The effect of supplemented nitrogens on the degradation of atrazine and sunazine was evalualed. Addition of a suppleinented nitrogen in he growth medium containing ah-azine or siinazine showed partial degr-adation olihose herbicides duriug the incubation period. However, complete degradation of atrazine and simazu~e was examined ul the absence or any supplemented nitrogens. Addltion of yeast extract in this study was inhibilory to atrazine aud siinazine degradations, respectively. TNT-degrader was a small Gram-negative cocco-bacillus. Physiological analysis using BIOLOG sysleln revealed that this strain was Ste~~ol~~opl~orno~~ns rrialtophilia.

• Journal of Microbiology and Biotechnology
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• v.31 no.10
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• pp.1455-1464
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• 2021

Trehalose is a non-reducing disaccharide in increasing demand for applications in food, nutraceutical, and pharmaceutical industries. Single-step trehalose production by trehalose synthase (TreS) using maltose as a starting material is a promising alternative process for industrial application due to its simplicity and cost advantage. Pseudomonas monteilii TBRC 1196 was identified using the developed screening method as a potent strain for TreS production. The TreS gene from P. monteilii TBRC 1196 was first cloned and expressed in Escherichia coli. Purified recombinant trehalose synthase (PmTreS) had a molecular weight of 76 kDa and showed optimal pH and temperature at 9.0 and 40℃, respectively. The enzyme exhibited >90% residual activity under mesophilic condition under a broad pH range of 7-10 for 6 h. Maximum trehalose yield by PmTreS was 68.1% with low yield of glucose (4%) as a byproduct under optimal conditions, equivalent to productivity of 4.5 g/l/h using enzyme loading of 2 mg/g substrate and high concentration maltose solution (100 g/l) in a lab-scale bioreactor. The enzyme represents a potent biocatalyst for energy-saving trehalose production with potential for inhibiting microbial contamination by alkaline condition.

• Journal of Microbiology and Biotechnology
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• v.31 no.9
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• pp.1311-1322
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• 2021

Microbially induced calcium carbonate precipitation (MICP) has recently become an intelligent and environmentally friendly method for repairing cracks in concrete. To improve on this ability of microbial materials concrete repair, we applied random mutagenesis and optimization of mineralization conditions to improve the quantity and crystal form of microbially precipitated calcium carbonate. Sporosarcina pasteurii ATCC 11859 was used as the starting strain to obtain the mutant with high urease activity by atmospheric and room temperature plasma (ARTP) mutagenesis. Next, we investigated the optimal biomineralization conditions and precipitation crystal form using Plackett-Burman experimental design and response surface methodology (RSM). Biomineralization with 0.73 mol/l calcium chloride, 45 g/l urea, reaction temperature of 45℃, and reaction time of 22 h, significantly increased the amount of precipitated calcium carbonate, which was deposited in the form of calcite crystals. Finally, the repair of concrete using the optimized biomineralization process was evaluated. A comparison of water absorption and adhesion of concrete specimens before and after repairs showed that concrete cracks and surface defects could be efficiently repaired. This study provides a new method to engineer biocementing material for concrete repair.

• Journal of the Korean Applied Science and Technology
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• v.35 no.4
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• pp.1276-1284
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• 2018

probiotics strains promoting the health are a collection of microorganisms that improve or restore microbial populations in the intestines. In this study, Leuconostoc probiotics was isolated from fermented gimchi and identified. Angelica dahurica, containing abundantly antioxidant activity, imperator, is a wildly grown species of angelica native. Before fermentation, total phenolics compound were $48.83{\pm}4.9GAE\;mg/g$ in the Angelica dahurica extract. After fermentation total phenolic compounds were $97.7{\pm}12.6GAE\;mg/g$. The total amount of phenol in the fermented product was 30.2% higher than that before fermentation. The total flavonoid content before fermentation was $9.86{\pm}4.3mg/g$ and the total flavonoid content was $37.17{\pm}7.4mg/g$ after fermentation, which was 82.3% higher than before fermentation. The DPPH radical scavenging activity, superoxide radical scavenging activity, hydroxy radical scavenging activity and $Fe^{{+}{+}}$ chelating antioxidative activity of the Angelica dahurica extract were $41.6{\pm}7.1%$, $65.7{\pm}8.4%$, $55.26{\pm}9.4%$ and $17.5{\pm}4.6%$, respectively. After fermentation, they were $60.3{\pm}12.6%$, $78.8{\pm}8.3%$, $56.9{\pm}4.9%$ and $36.6{\pm}8.9%$, respectively. Therefore, the present study suggests that the fermentation using the probiotics strain of the Angelica dahurica extract can be used as a functional health food and cosmetic material with increased antioxidant capacity.