• Microbiology and Biotechnology Letters
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• v.52 no.1
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• pp.76-87
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• 2024

Halophilic bacteria are promising reservoirs for halotolerant enzymes that have gained much attention in biotechnological applications due to their remarkable activity and stability. In this study, 62 halophilic bacterial strains isolated from a solar saltern were screened for the production of various extracellular enzymes. The results revealed that 31 strains (50%) were positive for amylase production while 26 strains (41.9%) were positive for protease. Further, 22 strains (35.48%) exhibited β-glucosidase activity and only 17 (27.41%) demonstrated lipase activity. Of the investigated halophiles, ten strains growing in the presence of ≥15% NaCl (w/v) were selected and identified based on their 16S rRNA gene sequences as Halomonas meridiana, Salinivibrio costicola, Virgibacillus oceani, Virgibacillus marismortui, Marinobacter lipolyticus, Halobacillus karajensis, Salicola salis, Pseudoalteromonas shioyasakiensis, Salinicoccus amylolyticus, and Paracoccus salipaludis. Therefore, the present study highlights the diversity of the culturable halophilic bacteria in a Mediterranean solar saltern, harboring various valuable halotolerant enzymes.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.5
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• pp.314-324
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• 2011

Algal biomass cultivated by wastewater is potentially useful resource for biodiesel production. However, little is known about algal nutrient metabolism and microbial interaction with bacteria under real municipal wastewater condition. In this work, we characterized nitrogen and phosphorus removals of municipal wastewater by a representative wastewater-growing algal population. Ankistrodesmus gracilis SAG 278-2, and analyzed its ecological interaction with wastewater bacterial communities. Compared to wastewater sludge itself, algal-bacterial co-culture improved nutrient removal. According to bacterial community analysis with 16S rRNA genes, a selective and dominant growth of a Unclassified Alcaligenaceae population resulted from algal growth in the algal-bacterial co-culture. The selectively stimulated bacterial population is phylogenetically close to Alcaligenes faecalis subsp. 5659-H, which is known to be co-present interact with algae in aquatic environment. These findings suggest that algal growth/metabolism may have effects on selection of a specific bacterial population in algal-bacterial co-cultures that can efficiently remove nutrients from municipal wastewater.

• Journal of Environmental Science International
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• v.29 no.8
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• pp.819-826
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• 2020

Production of Bacterial Cellulose (BC) by Gluconacetobacter sp. A5 was studied in shaken culture using different cost-effective carbon sources and its structural and mechanical properties were evaluated. Glycerol showed the highest level (7.26 g/l) of BC production, which was about three times higher than the yield in glucose medium. BC production depended not only on the decrease in pH, but also on the ability of Gluconacetobacter sp. A5 to synthesize glucose from different carbon sources and then polymerize it into BC. All BC produced from different carbon sources exhibited a three-dimensional reticulated structure consisting of ultrafine cellulose fibriles. Carbon sources did not significantly change the microfibrile structure of the resulting BC. BC produced from glucose medium had the lowest water-holding capacity, while BC from molasses medium had the highest. XRD data revealed that all BC were cellulose type I, the same as typical native cellulose. The crystalline strength of BC produced in glucose medium was the highest, and that in molasses medium was the lowest. Our results suggest that glycerol could be a potential low-cost substrate for BC production, leading to the reduction in the production cost, and also to produce BC with different mechanical properties by selecting appropriate carbon source.

• Food Industry And Nutrition
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• v.6 no.1
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• pp.1-9
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• 2001

• Proceedings of the Korean Nutrition Society Conference
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• 2001.05a
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• pp.259.1-259
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• 2001

• Preventive Nutrition and Food Science
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• v.7 no.1
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• pp.37-42
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• 2002

Factors affecting the production of bacterial cellulose and organic acids in Kombucha fermentation were investigated. Kombucha was obtained by the fermentation (for 12 days at 3$0^{\circ}C$) of the green/black tea extract, supplemented with 10% white sugar, using an Oriental tea fungus as starter. Hitgher initial pH increased acid production with decreased cellulose production. With a cellulose pellicle or tea fungus broth as a starter, a 1~3 mm thick cellulose layer developed as a top layer every four days, and was removed subsequently while continuing fermentation. Addition of 30 mL tea fungus broth (13%, v/v) in Kombucha fermentation resulted in maximum production of a cellulose pellicle, indicating weak acid production. Yield of cellulose production at an early stage of fermentation was also higher when Kombucha was inoculated with a cellulose pellicle. In fact, addition of 1% (v/v) alcoholic beverage in the Kombucha fermentation activated the cellulose production, coupled with four times higher acid production.

• The Journal of Korean Obstetrics and Gynecology
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• v.27 no.1
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• pp.81-100
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• 2014

Objectives: The object of this study was to observe the in vitro anti-bacterial and anti-inflammatory effects of six single aqueous herbal extracts-Quisqualis Fructus (QuF), Meliae Cortex (MeC), Arecae Semen (ArS), Crassirhizomae Rhizoma (CrR), Ulmi Pasta Semen(UlS), Torreyae Semen(ToS)- against Staphylococcus aureus (S. aureus) and Lipopolysaccharide(LPS)-activated Raw 264.7 cells. Methods: Anti-bacterial activities against S. aureus of aqueous extracts of QuF, MeC, ArS, CrR, UlS and ToS were detected using standard agar microdilution methods. In addition, the effects on the cell viability, prostaglandin $E_2$ ($PGE_2$), nitric oxide (NO), tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), interleukin (IL)-$1{\beta}$ and IL-6 productions of LPS activated Raw 264.7 cells were detected. The anti-bacterial and anti-inflammatory effects were respectively compared with lincomycin and piroxicam. Results: Minimal Inhibition Concentration (MIC) of aqueous extracts of QuF, MeC, ArS, CrR, UlS and ToS against S. aureus was respectively detected $5.625{\pm}4.075$ (3.125~12.500), $0.332{\pm}0.273$ (0.098~0.782), $1.094{\pm}0.428$ (0.782~1.563), $2.969{\pm}2.096$ (0.782~6.250), $9.375{\pm}4.419$ (3.125~12.500)>25 mg/ml. MIC of lincomycin was detected as $0.469{\pm}0.297$ (0.195~0.782) ${\mu}g/ml$ at same conditions. In addition, $ED_{50}$ against LPS-induced cell viabilities and cytokine releases of QuF, MeC, ArS, CrR, UlS and ToS was as follows - Cell viability: 66.370, 2.908, 1.747, 259.553, 18.150 and 34.160 mg/ml; NO production: 389.486, 0.294, 0.138, 523.060, 45.363 and 49.327 mg/ml; $PGE_2$ production: 114.271, 0.223, 0.046, 243.078, 8.829 and 28.947 mg/ml; TNF-${\alpha}$ production: 406.288, 0.343, 0.123, 9404.227, 125.406 and 140.775 mg/ml; IL-$1{\beta}$ production: 117.178, 0.135, 0.019, 237.451, 7.923 and 19.418 mg/ml; IL-6 production: 31.261, 0.105, 0.055, 128.434, 2.290 and 3.745 mg/ml. ED50 of piroxicam against LPS-induced cell viabilities, NO, $PGE_2$, TNF-${\alpha}$, IL-$1{\beta}$ and IL-6 were detected as 35.179, 6.552, 1.162, 7.273, 7.101 and $5.044{\mu}g/ml$, respectively at same conditions. Conclusions: All six single aqueous herbal extracts showed anti-bacterial effects against S. aureus, in the order of MeC, ArS, CrR, QuF and UlS aqueous extracts except for ToS; they did not showed any anti-bacterial effects (MIC>25 mg/ml). They also showed anti-inflammatory effects against LPS-activated Raw 264.7 cells in the order of ArS, MeC, UlS, ToS, QuF and CrR aqueous extracts. It means that the ArS and MeC will be showed favorable potent anti-bacterial and related anti-inflammatory effects.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.4
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• pp.603-615
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• 2008

Dietary fiber is an inevitable component in pig diets. In non-ruminants, it may influence many physiological processes in the gastrointestinal tract (GIT) such as transit time as well as nutrient digestion and absorption. Moreover, dietary fiber is also the main substrate of intestinal bacteria. The bacterial community structure is largely susceptible to changes in the fiber content of a pig's diet. Indeed, bacterial composition in the lower GIT will adapt to the supply of high levels of dietary fiber by increased growth of bacteria with cellulolytic, pectinolytic and hemicellulolytic activities such as Ruminococcus spp., Bacteroides spp. and Clostridium spp. Furthermore, there is growing evidence for growth promotion of beneficial bacteria, such as lactobacilli and bifidobacteria, by certain types of dietary fiber in the small intestine of pigs. Studies in rats have shown that both phosphorus (P) and calcium (Ca) play an important role in the fermentative activity and growth of the intestinal microbiota. This can be attributed to the significance of P for the bacterial cell metabolism and to the buffering functions of Ca-phosphate in intestinal digesta. Moreover, under P deficient conditions, ruminal NDF degradation as well as VFA and bacterial ATP production are reduced. Similar studies in pigs are scarce but there is some evidence that dietary fiber may influence the ileal and fecal P digestibility as well as P disappearance in the large intestine, probably due to microbial P requirement for fermentation. On the other hand, fermentation of dietary fiber may improve the availability of minerals such as P and Ca which can be subsequently absorbed and/or utilized by the microbiota of the pig's large intestine.

• Nutrition Research and Practice
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• v.11 no.1
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• pp.11-16
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• 2017

BACKGROUND/OBJECTIVES: Helicobacter pylori (H. pylori) colonization of the stomach mucosa and duodenum is the major cause of acute and chronic gastroduodenal pathology in humans. Efforts to find effective anti-bacterial strategies against H. pylori for the non-antibiotic control of H. pylori infection are urgently required. In this study, we used whey to prepare glycomacropeptide (GMP), from which sialic acid (G-SA) was enzymatically isolated. We investigated the anti-bacterial effects of G-SA against H. pylori in vitro and in an H. pylori-infected murine model. MATERIALS/METHODS: The anti-bacterial activity of G-SA was measured in vitro using the macrodilution method, and interleukin-8 (IL-8) production was measured in H. pylori and AGS cell co-cultures by ELISA. For in vivo study, G-SA 5 g/kg body weight (bw)/day and H. pylori were administered to mice three times over one week. After one week, G-SA 5 g/kg bw/day alone was administered every day for one week. Tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), IL-$1{\beta}$, IL-6, and IL-10 levels were measured by ELISA to determine the anti-inflammatory effects of G-SA. In addition, real-time PCR was performed to measure the genetic expression of cytotoxin-associated gene A (cagA). RESULTS: G-SA inhibited the growth of H. pylori and suppressed IL-8 production in H. pylori and in AGS cell co-cultures in vitro. In the in vivo assay, administration of G-SA reduced levels of IL-$1{\beta}$ and IL-6 pro-inflammatory cytokines whereas IL-10 level increased. Also, G-SA suppressed the expression of cagA in the stomach of H. pylori-infected mice. CONCLUSION: G-SA possesses anti-H. pylori activity as well as an anti-H. pylori-induced gastric inflammatory effect in an experimental H. pylori-infected murine model. G-SA has potential as an alternative to antibiotics for the prevention of H. pylori infection and H. pylori-induced gastric disease prevention.

• Journal of Microbiology and Biotechnology
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• v.30 no.10
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• pp.1500-1509
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• 2020

Drought is a major abiotic factor and has drastically reduced crop yield globally, thus damaging the agricultural industry. Drought stress decreases crop productivity by negatively affecting crop morphological, physiological, and biochemical factors. The use of drought tolerant bacteria improves agricultural productivity by counteracting the negative effects of drought stress on crops. In this study, we isolated bacteria from the rhizosphere of broccoli field located in Daehaw-myeon, Republic of Korea. Sixty bacterial isolates were screened for their growth-promoting capacity, in vitro abscisic acid (ABA), and sugar production activities. Among these, bacterial isolates YNA59 was selected based on their plant growth-promoting bacteria traits, ABA, and sugar production activities. Isolate YNA59 highly tolerated oxidative stress, including hydrogen peroxide (H₂O₂) and produces superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) activities in the culture broth. YNA59 treatment on broccoli significantly enhanced plant growth attributes, chlorophyll content, and moisture content under drought stress conditions. Under drought stress, the endogenous levels of ABA, jasmonic acid (JA), and salicylic acid (SA) increased; however, inoculation of YNA59 markedly reduced ABA (877 ± 22 ng/g) and JA (169.36 ± 20.74 ng/g) content, while it enhanced SA levels (176.55 ± 9.58 ng/g). Antioxidant analysis showed that the bacterial isolate YNA59 inoculated into broccoli plants contained significantly higher levels of SOD, CAT, and APX, with a decrease in GPX levels. The bacterial isolate YNA59 was therefore identified as Variovorax sp. YNA59. Our current findings suggest that newly isolated drought tolerant rhizospheric Variovorax sp. YNA59 is a useful stress-evading rhizobacterium that improved drought-stress tolerance of broccoli and could be used as a bio-fertilizer under drought conditions.