• The Korean Journal of Food And Nutrition
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• v.29 no.6
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• pp.978-984
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• 2016

Osteoporosis is a disease that often occurs in postmenopausal women. The purpose of this study was to examine the positive effects of Cheongukjang powder containing menaquinone-7 (MK-7) on bone health circulation in postmenopausal women. Fifty-six postmenopausal women were recruited into a randomised double-blind placebo-controlled trial. The participants were randomly assigned into two groups. For 12 weeks, one group received $800{\mu}g$ MK-7 in the form of Cheongukjang packs (CMK-7), and the other group received the same amount of identical-looking placebo packs containing barley meal for 12 weeks. Femoral bone mineral density (BMD), bone-specific alkaline phosphatase (ALP), deoxypyridinoline (DPD), osteocalcin (OSC), serum Ca, and serum P were measured at baseline (0 weeks) and 12 weeks. After 12 weeks in the CMK-7 group, it was found that BMD, serum Ca, and serum P had increased above the baseline (p<0.0001, p=0.0028, p<0.0001), whereas bone-specific ALP, DPD, and OSC had decreased below the baseline (p=0.0003, p<0.0001, p<0.0001). Therefore, MK-7 taken as Cheongukjang is expected to prevent osteoporosis in postmenopausal women.

• Journal of Microbiology and Biotechnology
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• v.30 no.5
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• pp.762-769
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• 2020

Vitamin K2 (menaquinone) is an essential vitamin existing in the daily diet, and menaquinone-7 (MK-7) is an important form of it. In a recent work, we engineered the synthesis modules of MK-7 in Bacillus subtilis, and the strain BS20 could produce 360 mg/l MK-7 in shake flasks, while the methylerythritol phosphate (MEP) pathway, which provides the precursor isopentenyl diphosphate for MK-7 synthesis, was not engineered. In this study, we overexpressed five genes of the MEP pathway in BS20 and finally obtained a strain (BS20DFHG) with MK-7 titer of 415 mg/l in shake flasks. Next, we optimized the fermentation process parameters (initial pH, temperature and aeration) in an 8-unit parallel bioreactor system consisting of 300-ml glass vessels. Based on this, we scaled up the MK-7 production by the strain BS20DFHG in a 50-l bioreactor, and the highest MK-7 titer reached 242 mg/l. Here, we show that the engineered strain BS20DFHG may be used for the industrial production of MK-7 in the future.

• Journal of Microbiology and Biotechnology
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• v.28 no.6
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• pp.902-908
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• 2018

Optimization of the culture medium to maximize menaquinone-7 (MK-7) production by Bacillus subtilis strain KCTC 12392BP in static culture was carried out using statistical experimental methods, including one factor at a time, fractional factorial design, and response surface methodology (RSM). Maltose (carbon source), tryptone (nitrogen source), and glycerol (activator) were identified as the key medium components for MK-7 synthesis by the fractional factorial design, and were selected for statistical optimization by RSM. The statistical analysis indicated that, in the range that was studied, maltose, tryptone, and glycerol were all critical factors having profound effects on the production of MK-7, with their coefficients for linear and quadratic all significant at the p < 0.05 level. The established model was efficient and feasible, with a determination coefficient ($R^2$) of 0.9419. The predicted concentrations of maltose, tryptone, and glycerol in the optimal medium were determined as 36.78, 62.76, and 58.90 g/l, respectively. In this optimized medium, the maximum yield of MK-7 reached a remarkably high level of $71.95{\pm}1.00{\mu}g/ml$ after 9 days of static fermentation, which further verified the practicability of this optimized strategy.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.158-158
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• 1998

The non-mevalonate pathway is a newly discovered isoprenoid biosynthetic pathway in some bacteria, cyanobacteria, algae and plants. Because isoprenoid metabolites (ubiquinone, menaquinone, undecaprenol) are essential for bacterial growth, this pathway may represent a novel target for antibacterial agents. Antibiotics with a unique mechanism of action are needed to combat the risk of antibiotic resistance that is a current worldwide problem. In order to study this pathway as viable target, it was necessary to verify use of the pathway in our model system, the bacterium Bacillus subtilis. Incubation experiments with [6,6-$^2$H$_2$]-D-glucose and [l-$^2$H$_3$]-deoxy-D-xylulose were conducted to provide labeled menaquinone-7 (MK -7), the most abundant isoprenoid in B. subtilis. $^2$H-NMR analysis of the MK-7 revealed labeling patterns that strongly support utilization of the non-mevalonate pathway. Another approach to study the pathway is by structure activity relationships of proposed inhibitors of the pathway. Fosmidomycin is a phosphonic acid with antibacterial activity known to inhibit isoprenoid biosynthesis in susceptible bacteria and may act by inhibiting the non-mevalonate pathway. Fosmidomycin and an N-methyl analog were synthesized and tested for antibacterial activity. Fosmidomycin was active against Escherichia coli and B. subtilis, while N-formyl-N-methyl-3-amino-propylphosphonic acid was inactive.

• Journal of Microbiology and Biotechnology
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• v.19 no.6
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• pp.588-595
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• 2009

A bacterial strain, YK-2, was isolated as a producer of trans glutaminase from a forest soil sample of Daegu, Korea. The isolate showed a G+C content of 72.7 mol%, contained meso-$A_2pm$ as the cell-wall amino acid, and possessed menaquinone MK-9 ($H_6$) and menaquinone MK-9 ($H_8$) at a ratio of 6:4. The chemotaxonomic analysis, as well as phylogenetic analysis based on the 16S rDNA sequence, identified the isolate as a member of Streptomyces platensis. For transglutaminase production, the optimum medium composition was determined to be 2% glucose, 1% polypeptone, 1% soy tone, and 0.1% $MnCl_2$. The transglutaminase was stable within the pH range of 5.0-9.0 and $30-45^{\circ}C$, and the optimum pH and temperature were pH 8.0 and $45^{\circ}C$, respectively, without any requirement for $Ca^{2+}$.

• Journal of Microbiology and Biotechnology
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• v.16 no.12
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• pp.1862-1867
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• 2006

A moderately halophilic, Gram-positive, spore-forming bacterium was isolated from the roots of Blutaparon portulacoides, a plant found in sandy soil parallel to the beach line in Restinga de Jurubatiba, Rio de Janeiro, Brazil. The strain, designated $M9^T$, was motile and strictly aerobic with rod-shaped cells. It grew in the absence of NaCl and up to 20% NaCl, and was able to hydrolyze casein and starch. Strain $M9^T$ had a cell-wall peptidoglycan based on L-Orn-D-Asp, the predominant menaquinone present was menaquinone-7 (MK-7), diaminopimelic acid was not found, and anteiso-$C_{15:0}$ and iso-$C_{15:0}$ were the major fatty acids. A phylogenetic analysis based on 16S rRNA gene sequences showed that strain $M9^T$ belonged to the genus Halobacillus and exhibited 16S rRNA gene similarity levels of 97.8-99.4% with the type strains of the other nine Halobacillus species. The DNA-DNA relatedness of strain $M9^T$ with H. trueperi, the closest relative as regards 16S rRNA gene similarity, and H. locisalis was 21% and 18%, respectively. Therefore, on the basis of phenotypic, genotypic, and phylogenetic data, strain $M9^T$ (=ATCC BAA-$1217^T$, =CIP $108771^T$, =KCTC $3980^T$) should be placed in the genus Halobacillus as a member of a novel species, for which the name Halobacillus blutaparonensis sp. nov. is proposed.

• Applied Biological Chemistry
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• v.41 no.3
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• pp.208-212
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• 1998

In order to develop an effective antifungal antibiotics, over 700 isolates of bacteria, mold and actinomytes were screened from soil, and LAM 97-44 were selected as a strain producing the strong antifungal antibiotics against Candida albicans. Morphological, cultural and physiological characteristics of LAM 97-44 were investigated for the indentification. The cell size of LAM 97-44 was $2{\sim}3{\times}1{\sim}1.5\;{\mu}m$, and the shape of spore was of ellipsoidal. As a carbon source, LAM 97-44 utilized fructose, glucose, glycerol, maltose and raffinose but did not utilize arabinose, cellulose and xylose. The fatty acids of the cells included various iso-type and anteiso-type. Conclusively, the strain LAM 97-44 was proved to be Bacillus subtilis.

• Microbiology and Biotechnology Letters
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• v.45 no.2
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• pp.168-177
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• 2017

Strain A28-5, which can degrade xylan and agar in solid medium, was isolated from a coastal seawater sample collected from Jeju Island, South Korea. This strain was found to be a gram-negative, $Na^+$-requiring bacterial strain with a polar flagellum for motility. Additionally, the strain was tolerant to antibiotics such as ampicillin and thiostrepton. The G+C content of the genome was 43.96% and menaquinone-7 was found to be the predominant quinone. Major fatty acids constituting the cell wall of the strain were $C_{16:1}$ ${\omega}7c/iso-C_{15:0}$ 2-OH (23.32%), $C_{16:0}$ (21.83%), and $C_{18:1}$ ${\omega}7c$ (17.98%). The 16S rRNA gene sequence of the strain showed the highest similarity (98.94%) to that of Catenovulum agarivorans YM01, which was demonstrated by constructing a neighbor-joining phylogenetic tree. A28-5 was identified as a novel species of the genus Catenovulum via DNA-DNA hybridization with Catenovulum agarivorans YM01, and thus was named as Catenovulum jejuensis A28-5. The formation of tetramers and hexamers of xylooligosaccharides and (neo)agarooligosaccharides, respectively, were confirmed by thin-layer chromatography analysis using an enzyme reaction solution containing xylan or agarose with two crude enzymes prepared from the liquid culture of the strain.

• Korean Journal of Microbiology
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• v.33 no.3
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• pp.187-192
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• 1997

The strain producing biosurfactant was isolated from soil. The isolated strain was identified as the genus Tsukamurella through its morphological, cultural, physiological, menaquinone type, fatty acid composition characteristics. The highest biosurfactant production by Tsukamurella sp. 26A was observed after 4 days cultivation in the culture medium containing n-hexadecane 7%, $NaNO_{3}$ 0.2%, $K_2HPO_4$ 0.001%, $MgSO_{4}$ center dot $7H_{2}O$ 0.02%, $CaCl_2$ center dot $2H_{2}O$ 0.02%, yeast extract 0.02%(pH 6.8-7.0, 30^{\circ}C.$ The surface and interfacial tension of an aqueous solution reached 30 mNim and 1.5 mNim, respectively. The biosurfactant stabilized oil-in-water emulsion with a variety of hydrocarbons, edible oils and petroleum oils.

• Journal of the East Asian Society of Dietary Life
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• v.27 no.3
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• pp.341-347
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• 2017

This study was carried out to investigate the characteristics and Vitamin $K_2$ (MK-7) productivity of Cheonggukjang fermented by Bacillus subtilis SRCM100757 depending on the inoculum concentration 0.5% (v/w), 1% (v/w) and 2% (v/w). The lowest moisture content and water activity were $53.7{\pm}0.6%$ and $8.39{\pm}0.09$ after fermentation for 72 hours at 2% (v/w). pH slowly became alkalized during fermentation, but there was no significant difference. Amino nitrogen content increased with time and the highest content was $580.8{\pm}1.9mg%$ after fermentation for 72 hours at 2% (v/w). Lightness (L value) and yellowness (b value) decreased with time, whereas redness (a value) hardly changed. MK-7 contents increased with time at each inoculum concentration. The highest content was $20.47{\pm}1.53$ after fermeatation for 72 hours at 2%(v/w) and there were no significant differences between 1%(v/w) and 2%(v/w) inoculum concentrations.