• Microbiology and Biotechnology Letters
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• v.49 no.2
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• pp.255-263
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• 2021

In this study, we assessed the technological characteristics and safety of 88 Enterococcus faecium strains isolated from meju; the strains possess the glutamate decarboxylase gene gadA/B involved in γ-aminobutyric acid production. The study was conducted to evaluate the possibility of introducing E. faecium meju isolates as food fermentation starters. We observed that a NaCl concentration of 6% (w/v) facilitated the growth and acid production of all strains. At a NaCl concentration of 7%, 21 strains (24%) exhibited a low growth rate, 72 strains (82%) a weak acid production, and 16 strains (18%) showed no acid production. All strains exhibited protease activity at a NaCl concentration of 4%. At a NaCl concentration of 5%, 86 strains exhibited weak activity, and one strain showed no protease activity. We could not detect any lipase activity in the investigated strains. None of the strains exhibited an acquired antibiotic resistance to the seven antibiotics tested in the present study, namely ampicillin, chloramphenicol, ciprofloxacin, gentamicin, penicillin G, tetracycline, and vancomycin. We could identify the Enterococcus endocarditis antigen gene efaA and the tyrosine decarboxylase gene tdc contributing to tyramine production, in 88 meju isolates. We could not detect the Enterococcus surface protein gene esp, which is specifically possessed by human-originated E. faecium strains, in any of the 88 strains tested in the study.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.767-770
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• 2001

Experiments were accomplished to reduce the extent of proteolysis by simply controlling the culture conditions instead of the gene manipulation techniques. L-arginine and L-lysine were chosen as a protease inhibitor analogue With the assumption that they might act as the potential inhibitors against proteases involved in the rHSA proteolysis. The addition of arginine and lysine resulted in a considerable positive effect on the secreted rHSA production level.

• Journal of Microbiology and Biotechnology
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• v.17 no.6
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• pp.919-927
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• 2007

Antagonistic fluorescent pseudomonads isolated from rhizospheric soil of rice were characterized by 16S rRNA amplicon and fatty acid methyl ester (FAME) analyses. Antagonistic isolates were grown in the fermentation media, and production of antibiotics was confirmed by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). Production of fungal cell-wall-degrading enzymes such as protease, cellulase, pectinase, and chitinase was determined. Dendrogram based on the major and differentiating fatty acids resulted into 5 clusters, viz., cluster I (P. pseudoalcaligenes group), cluster II (P. plecoglossicida group), cluster III (P. fluorescens group), cluster IV (P. aeruginosa group), and cluster V (P. putida group). Characteristic presence of high relative proportions of cyclopropane (17:0 CYCLO w7c) was observed in antagonistic bacteria. Data revealed biodiversity among antagonistic fluorescent pseudomonads associated with the rice rhizosphere. Results presented in this study will help to identify the antagonistic isolates and to determine their mechanisms that mediate antagonism against fungal pathogens of rice.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.5
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• pp.784-787
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• 1997

Enzymatically hydrolyzed soy sauce(eHSS) was prepared by the treatment of defatted soy flake using two types of proteases, followed by maillard reaction and formulation with some ingredients. The eHSS was mixed with fermented soy sauce(FSS) to make enzymatically hydrolyzed mixed soy sauce(eHMSS). The properties and sensory characteristics were evaluated and compared with commercially available soy sauces. The control of salt and total nitrogen contents in eHSS and eHMSS was easy, and the production of soy sauce of low salt and high protein was possible. However, the free amino acid content of eHSS was lower than FSS. due to lower degree of hydrolysis. In sensory evaluation, the eHSS have no loss taste and overall acceptance than FSS. Consequently, the eHSS and eHMSS have the potential for use with FSS to produce high quality soy sauce of low salt and high protein contents.

• 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 the Korean Society of Food Science and Nutrition
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• v.35 no.1
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• pp.115-120
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• 2006

To convert the soybean curd residue (SCR) to functional food ingredient, alkaline fermentation of SCR was performed by Bacillus firmus NA-1 and Bacillus subtilis GT-D for 22 hr at $42^{\circ}C$. The micronized full-fat soy flour (MFS) was fortified to reduce the moisture content as well as to supply protein source. The mucilage and flavor productions in the fermented SCR were enhanced by the fortification of $20\%$ MFS. The peptide production from the SCR fermented with B. subtilis GT-D substantially increased when judged by the detectable amount of tyrosine $(480\;mg\%)$. The production of fibrinolytic enzyme was increased by the fermentation for 22 hr, indicating the relative activity of $62\%$ (B. firmus NA-1) and $47\%$ (B. subtilis GT-D), respectively. The SCR fermented by B. firmus NA-1 and B. subtilis GT-D indicated the consistency of $1.95\;Pa{\cdot}s^n\;and\;0.21\;Pa{\cdot}s^n$, respectively. After freeze-drying, the protease activity (615 unit/g) and a-amylase activity (180 unit/g) were obtained from SCR fermented by Bacillus firmus NA-1 and Bacillus subtilis GT-D, respectively.

• Journal of Life Science
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• v.17 no.12
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• pp.1682-1688
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• 2007

To develop multifunctional microbial inoculant, microorganisms with antagonistic activity and biofertilizing activity were screened. Pantoea agglomerans and Bacillus megaterium from our laboratory culture collection, and strain MF12 from soil near poultry farm in Miryang were selected. On the basis of morphological, physiological studies and 16S rDNA sequence analysis, isolate MF12 was identified as the Bacillus pumilis. Three strains were studied for insoluble phosphate solubilization, indole-3-acetic acid (IAA) and siderophore production, ammonification ability, hydrolytic enzyme production and antifungal activity against phytopathogenic fungi. P. agglomerans did not produce any visible clear zone on agar plate containing 0.5% $Ca_3(PO_4){_2}$ as a sole phosphorus source. However, this strain could solubilize insoluble phosphate in liquid medium. All strains produced IAA ranged from $3{\sim}639{\mu}g/ml$ depending on culture time and had ammonification ability. Among three strains, only P. agglomerans produced siderophore. P. agglomerans produced pectinase and lipase, B. megaterium produced amylase, protease and lipase while B. pumilis produced protease and lipase. P. agglomerans showed antifungal activities against phytopathogenic fungi, Fusarium oxysporum and Colletotrichum gloeosporioides. B. pumilis showed antifungal activities against Botrytis cinerea, Sclerotinia sclerotiorum and Phythium ultimum.

• Journal of Microbiology
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• v.44 no.6
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• pp.622-631
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• 2006

In this study we purified a fibrinolytic enzyme from Cordyceps militaris using a combination of ion-exchange chromatography on a DEAE Sephadex A-50 column, gel filtration chromatography on a Sephadex G-75 column, and FPLC on a HiLoad 16/60 Superdex 75 column. This purification protocol resulted in a 191.8-fold purification of the enzyme and a final yield of 12.9 %. The molecular mass of the purified enzyme was estimated to be 52 kDa by SDS-PAGE, fibrin-zymography, and gel filtration chromatography. The first 19 amino acid residues of the N-terminal sequence were ALTTQSNV THGLATISLRQ, which is similar to the subtilisin-like serine protease PR1J from Metarhizium anisopliae var. anisopliase. This enzyme is a neutral protease with an optimal reaction pH and temperature of 7.4 and $37^{\circ}C$, respectively. Results for the fibrinolysis pattern showed that the enzyme rapidly hydrolyzed the fibrin $\alpha$-chain followed by the $\gamma$-$\gamma$ chains. It also hydrolyzed the $\beta$-chain, but more slowly. The A$\alpha$, B$\beta$, and $\gamma$ chains of fibrinogen were also cleaved very rapidly. We found that enzyme activity was inhibited by $Cu^{2+}$ and $Co^{2+}$, but enhanced by the additions of $Ca^{2+}$ and $Mg^{2+}$ ions. Furthermore, fibrinolytic enzyme activity was potently inhibited by PMSF and APMSF. This enzyme exhibited a high specificity for the chymotrypsin substrate S-2586 indicating it's a chymotrypsin-like serine protease. The data we present suggest that the fibrinolytic enzyme derived from the edible and medicinal mushroom Cordyceps militaris has fibrin binding activity, which allows for the local activation of the fibrin degradation pathway.

• Journal of Plant Biotechnology
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• v.33 no.1
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• pp.27-32
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• 2006

To clarify the roles of bromelain in plants, we isolated BL1 gene encoding bromelain from pineapple stem tissues and sequenced. The full length cDNA is 933 bp and encodes a polypeptide of 311 amino acid residues. The cDNA is most similar 94% at the amino acid level to bromelain previously isolated from pineapple (BAA21929). Explants of Lactuca sativa were co-cultivated with Agrobacterium tume-faciences LBA 4404 strains containing nptII and BL1 gene for transformation. Through initial selection of regenerated explants by culturing on a kanamycin and carbenicillin containing MS medium, multiple shoots were obtained after 2 months of culture. For a complementary step of selection, putative transgenic shoots were transferred to 1/2 Ms basal medium supplemented with 100 mg/L kanamycin and 500 mg/L carbenicillin. The selected shoots were obtained T1 generation seeds with emasculation, and tested with PCR analysis using 35S promoter and BL1 specific primers whether BL1 gene was introduced to genome of the plants. These results confirmed that produced the specific PCR bands in the putative transgenic lines. Additionally the Northern blot and endo protease activity showed that transcripts of BL1 gene were detected in transgenic lines. Theses results suggest that BL1 gene be successfully integrated and transcripted in the transgenic lettuce plants.

• Applied Biological Chemistry
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• v.51 no.4
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• pp.281-287
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• 2008

Effect of combined use of anti-microbial materials, such as alcohol, mustard and chitosan, or pasteurization on the quality of low salted kochujang was investigated during storage at $30^{\circ}C$ for 12 weeks. Activity of amylase decreased during storage, with lower activity in pasteurized kochujang than the other groups. Acidic protease activity increased during storage, but neutral protease activity decreased after 4 weeks. Viable cells of yeast increased during storage, but bacterial counts decreased gradually and did not show any remarkable difference among the test groups. Hunter a-values decreased as storage time increased, whereas L- and b-values decreased after 4 weeks and the degree of increase in total color difference (${\Delta}E$) was low in the supplementary ingredients added kochujang. The moisture contents and water activities decreased during storage with being lower in supplementary ingredients added groups. Titratable acidity of kochujang was decreased after 4 weeks of storage with the highest in combination of the supplementary ingredients added group. Oxidation-reduction potential was low in the supplementary ingredients added kochujang. Total sugar and reducing sugar contents of kochujang decreased during storage, with the highest contents in the supplementary ingredients added group. Ethanol content of kochujang increased during storage, whereas ethanol production was reduced in ethanol added one. Amino-nitrogen and ammonia-nitrogen contents decreased during storage with being lower in kochujang prepared with supplementary ingredients. Therefore, supplementary ingredients added kochujang would be effective for extending shelf-life of kochujang.