• The Korean Journal of Mycology
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• v.44 no.1
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• pp.36-47
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• 2016

This study was conducted to evaluate five different strains of rhizobacterial isolates viz. PA1, PA2, PA4, PA5 and PA12 for biological control against Colletotrichum acutatum, C. coccodes, C. gloeosporioides, C. dematium, Botrytis cinerea, Rhizoctonia solani, Sclerotinia minor and Fusarium sp. In vitro inhibition assay was performed on three different growth mediums, potato dextrose agar (PDA), tryptic soy agar (TSA), and PDA-TSA (1:1 v/v) for the selection of potential antagonistic isolates. According to the result, isolate PA2 showed the highest inhibitory effect with 65.5% against C. coccodes on PDA and with 96.5% against S. minor on TSA. However, the same isolate showed the highest inhibition with 58.5% against C. acutatum on PDA-TSA. In addition, an in vivo experiment was performed to evaluate these bacterial isolates for biological control against fungal pathogens. Plants treated with bacteria were analyzed with phytopathogens and plants inoculated with phytopathogens were treated with isolates to determine the biological control effect against fungi. According to the result, all five isolates tested showed inhibitory effects against phytopathogens at various levels. Mode of action of these rhizobacterial isolates was evaluated with siderophore production, protease assay, chitinase assay and phosphate solubilizing assay. Bacterial isolates were identified by 16S rDNA sequencing, which showed that isolates PA1 and PA2 belong to Bacillus subtilis, whereas, PA4, PA5, and PA12 were identified as Bacilus altitudinis, Paenibacillus polymyxa and Bacillus amyloliquefaciens, respectively. Results of the current study suggest that rhizobacterial isolates can be used for the plant growth promoting rhizobacteria (PGPR) effect as well as for biological control of various phytopathogens.

• Food Science and Preservation
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• v.18 no.2
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• pp.171-177
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• 2011

In order to demonstrate the usefulness of Deodeok. the functions of Deodeok and the qualities of Cheongkukjang were investigated. DPPH (1.1-diphenyl-2-picryl-hydrazyl) radical scavenging activity of Deodeok extracted with 70% ethanol was higher than that of water extract. The direct antimutagenic effect of ethanol extract of Deodeok was examined by Ames test using Salmonella typimurium TA 98. The inhibition rates on ethanol extract at concentrations of 200, 1.000, 2.000, 3.000 and 4.000 ${\mu}g$/plate were 5.75, 31.38, 34.75, 53.50 and 83.75%, respectively. The inhibition rates of ethanol extract was higher over 2 times than that of water extract. The qualities including physicochemical and sensory properties of Deodeok Cheongkukjang were investigated over the following range of Deodeok levels; 5, 10, 15 and 20% (w/w). The strain used in Cheongkukjang manufacture was Bacillus sp. B-3 with the highest enzyme activities such as amylase and protease. During fermentation at $40^{\circ}C$ for 6 days. amino-type nitrogen content of Cheongkukjang containing 10% (w/w) Deodeok was more than others. When Deodeok content exceeded 15% (w/w), higher contents resulted in lesser amino-type nitrogen production. The results showed that Deodeok had influenced the growth of Bacillus sp. B-3. The L-value of Deodeok Cheongkukjang was decreased according to increasing the Deodeok contents. Sensory evaluation showed that Deodeok Cheongkukjang containing 10% (w/w) Deodeok was superior to other tested.

• KSBB Journal
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• v.31 no.4
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• pp.277-283
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• 2016

In this system, rice cells were genetically modified to express human cytotoxic T-lymphocyte antigen 4-immunoglobulin (hCTLA4Ig) using RAmy3D promoter induced by sugar depletion. Even though the target protein fused with signal sequence peptide, plant cell wall can be a barrier against secretion of recombinant proteins. Therefore, hCTLA4Ig can be trapped inside cell wall or remained in intracellular space. In this study, to enhance the secretion of hCTLA4Ig from cytoplasm and cell walls into the medium, permeabilizing agents, such as dimethyl sulfoxide (DMSO), Triton X-100 and Tween 20, were applied in transgenic rice cell cultures. When 0.5% (v/v) of DMSO was added in sugar-free medium, intracellullar hCTLA4Ig was increased, on the other hand, the secreted extracellular hCTLA4Ig was lower than that of control. DMSO did not give permeable effects on transgenic rice cell cultures. And Triton X-100 was toxic to rice cells and also did not give enhancing permeability of cells. When 0.05% (v/v) Tween 20 was added in rice cell cultures, however, intracellular hCTLA4Ig was lower than that of control cultures. And the maximum 44.76 mg/L hCTLA4Ig was produced for 10 days after induction, which was 1.4-fold increase compared to that of control cultures. Especially, Tween 20 at 0.05% (v/v) showed the positive effect on the secretion of hCTLA4Ig though the decrease of intracellular hCTLA4Ig. Also, Tween 20 as a non-toxic surfactant did not affect the cell growth, cell viability and protease activity. In conclusion, secretion of hCTLA4Ig could be increased by enhancing permeability of cells regardless of the cell growth, cell viability and protease activity.

• Korean journal of food and cookery science
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• v.11 no.1
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• pp.26-32
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• 1995

This study was carried out to investigate the effect of protease on the functionality of soymilk protein. The protease from Bacillus polymyxa was selected because of the least production of bitter taste and calcium-aggregation. The results are summarized as follows: 1. Solubility of SMP(soymilk protein) and SPI(soyprotein isolate) were lowest at pH 4.7 and increased as the pH value reached closer to either ends. PT-SMP(pretense treated soymilk protein) showed higher solubility at all pH range, especially at pH 4.7 than SMP, SPI. 2. Emulsion activity of three samples was lowest at pH 4.7 and significantly increased as pH approched higher acidic or alkaline regions. PT-SMP showed similar activity to other samples, but less stability. 3. Foam capacity of PT-SMP was lowest at pH 8 and increased in acidic, alkaline pH. PT-SMP showed higher foam capacity at all pH range, but lower foam stability than SMP and SPI. 4. PT-SMP showed higher heat coagulability than other samples at all pH range except pH 4.7.

• Korean Journal of Agricultural Science
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• v.11 no.1
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• pp.8-24
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• 1984

In this study, investigated the effects of four strains belonging to Aspergillus oryzae on the quality of Kochujang. In the Koji and Kochujang making, investigated the difference of enzyme production of each strain, the change of each component and color during the aging, and tested the sensory taste. The results obtained were as follows; 1. Protease activity (acid, neutral) in wheat flour Koji was high in the case of Aspergillus $oryzae-S_1$ and Aspergillus oryzae - M of short stalked type. The strain Aspergillus $oryzae-S_1$ showed maximum activity after two days of Koji making, while the strain Aspergillus oryzae - M showed low activity till two days, but showed maximum activity after three days-four days of Koji making. 2. In $\alpha$-amylase activity, strain Aspergillus $oryzae-S_1$, Aspergillus $oryzae-S_2$ and Aspergillus oryzae - M showed high activity after two days of Koji making. Aspergillus oryzae-NB strain showed slower ${\alpha}$ - amylase activity than that strains. 3. In glucoamylase activity, all strain tested showed high activity after three days of Koji making, but st rain Aspergillus oryzae - NB showed slower activity than ot - hers. 4. In protease activity (acid, neutral) during the aging of Kochujang, strain Aspergillus $oryzae-S_1$ and Aspergillus oryzae - M of short stalked type showed higher activity than that of long stalked type. 5. Amino type nitrogen contents during the aging of Kochujang was very higher in the case of strains Aspergillus $oryzae-S_1$ and Aspergillus oryzae - M of short stalked type than other strains, and each contents was 315mg% and 337mg% after aged for ninty days. 6. The results that analysed free sugar of Kochujang aged for ninty days with HPLC were; glucose 5.84~7.13%, fructose 4.13~5.00%, rhamnose 0.91~1.04%, maltose 0.72~0.92% and presence of xylose was recognized. 7. The results that analysed alcohols of Kochujang aged for ninty days with gas chromatography were; ethanol 1.51~1.78%, n-propyl alcohol 1.13~1.20mg%, iso-amyl alcohol 3.5~4.4mg%. 8. In the sensory test of Kochujang aged for sixty days and for ninty days, the case of strains Aspergillus oryzae-M and Aspergillus $oryzae-S_1$ of short stalked type showed good taste, while the case of strains Aspergillus $oryzae-S_2$ and Aspergillus oryzae-NB of long stalked type showed good flavor and color.

• Research in Plant Disease
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• v.26 no.1
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• pp.8-18
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• 2020

Red pepper, one of the major economic crops in Korea, is being affected by anthracnose disease caused by Colletotrichum acutatum. To control this disease, an antagonistic bacterial strain, Bacillus subtilis YGB36 identified by 16S rDNA sequencing, physiological and biochemical analyses is used as a biological control agent. In vitro screening revealed that the strain YGB36 possess strong antifungal activity against the pathogen Cylindrocarpon destructans. The strain exhibited cellulase, protease, amylase, siderophore production and phosphate solubility. In vitro conidial germination of C. acutatum was most drastically inhibited by YGB36 cell suspensions (10⁶ cfu/ml) or culture filtrate. Development of anthracnose symptoms was reduced on detached immature green pepper fruits by treatment with cell suspensions, and its control value was recorded as 65.7%. The YGB36 bacterial suspension treatment enhanced the germination rate of red pepper seeds and promoted root development and growth under greenhouse conditions. The in vitro screening of fungicide and insecticide sensitivity test against YGB36 revealed that the bacterial growth was not affected by any of the insecticides, and 11 fungicides out of 21 used. Collectively, our results clearly suggest that the strain YGB36 is considered as one of the potential biocontrol agents against anthracnose disease in red pepper.

• Food Science of Animal Resources
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• v.27 no.3
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• pp.363-370
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• 2007

In order to identify probiotic microorganisms, 25 isolates of Lactobacillus sp. were selected from kimchi based on their growth rates, lactic acid production and salt tolerance. The isolate JK-01 was identified as Lactobacillus plantarum by the API kit and 16S rDNA analysis (99.9% of homology), and named as L. plantarum JK-01. The maximum number of L. plantarum JK-01 was reached at 18 hr fermentation in MRS broth and the pH gradually decreased to 4.5. L. plantarum JK-01 showed high enzyme activities for xylanase, amylase, protease, and phytase on MRS agar plates containing each substrate. L. plantarum JK-01 showed high resistance to acidic pH and bile salts, and grew well even at pH 2.0 and 1.0% bile salt. In particular, L. plantarum JK-01 showed high heat stability as shown by $3.3{\times}10^3$ CFU/mL at $60^{\circ}C$. The isolate showed remarkable antimicrobial activity against E. coli in MRS broth based on its disappearance after 18 hr and clear zone formation using a paper disk assay. These results suggest that L. plantarum JK-01 may be probiotic in nature.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.5
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• pp.756-762
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• 2014

This study evaluated the quality characteristics of soybean fermented with several Bacillus sp., which were selected based on their high enzymatic and antimicrobial activities. Total aerobic bacterial counts of fermented soybeans with HJ5-2 ($3.00{\times}10^9CFU/mL$) were the highest among all strains. Lactic acid bacteria numbered $2.50{\times}10^2{\sim}7.30{\times}10^4CFU/mL$ in soybeans fermented with isolates. Amylase and protease activities of the RD7-7 sample were the highest among all strains. Reducing sugar and amino-type nitrogen contents of fermented soybeans with HJ18-4 (2.35%) and RD7-7 (227.96 mg%) were the highest. Total amino acid contents of the samples were 16.62~18.38%, and glutamic acid, aspartic acid, leucine, lysine, arginine were major amino acids. Oxalic acid (36.51~63.57 mg/100 g) and succinic acid (429.49~600.15 mg/100 g) were the predominant organic acid. These results provide useful information for development starter (single and complex) as well as for the production of high quality fermented soybean foods.

• Korean Journal of Food Science and Technology
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• v.15 no.4
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• pp.385-391
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• 1983

The change of free amino acid contents and nitrogen compounds in the course of the Chungkookjang fermentation that occurred by utilizing Bacillus natto and Bacillus subtilis are to the following effects. pH, during the growth period, that is 6.35 in pH at the first stage of fermentation, were turned into 8.2 after 72 hours. Crude protein content increased irregularly from 16.82%-18% and total sugar decreased. Increasing with the progress of fermentation time, protease activity showed the maximum value between 48-60 hours, but Bacillus natto activated a little than Bacillus subtilis. Amino nitrogen and water soluble nitrogen content increased but difference was found that is, Bacillus natto increased more than Bacillus subtilis. Glutamic acid content was the highest among the contents of free amino acid between both Bacillus sp. and the order of the next contents showed as leucine, phenylalanine, histidine alanine. arginine, but difference was found between Bacillus sp., that is, Bacillus natto was higher than Bacillus subtilis. In view of the results as above, Bacillus natto was excellent than Bacillus subtillus as Bacillus strains of Chungkookjang koji production.

• Applied Biological Chemistry
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• v.50 no.2
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• pp.87-94
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• 2007

A bacterium which has high enzymatic activities such as amylase, cellulase and protease was isolated from Korean traditional soybean food, doenjang. The isolated bacterium was identified to Bacillus subtilis HS25 by the test of morphological and biochemical properties according to Bergey's Manual of Systematic Bacteriology and API 50 CHL kit, and by the 16S rDNA sequence. The isolated B. subtilis HS25 had a potent antibacterial activity against food born causative or pathogenic bacteria. B. subtilis HS25 is endospore forming cell and contained flagella and abundant viscous material at the out layer of cell wall. It was rod type bacterium $(0.5{\sim}0.8{\times}3{\sim}5{\mu}m)$ having biochemical characteristics such as gram staining(+), catalase(+), oxidase(-) and hydrolysis of esculin(+). The optimal medium compositions for production of antibacterial substance in the B. subtilis HS25 were 1% of soluble starch, 0.5% of yeast extract, 0.5% of peptone and 0.05% of MgCl$_2{\cdot}6H_{2}O$. The optimum temperature and pH of the growth of the B. subtilis HS25 was 35$^{\circ}C$ and pH 7.5, respectively. The antibacterial activity was more high in neutral to a little alkaline pH (6.5-10.5) than in acidic pH. The optimal shaking speed to grow and to produce antibacterial substance of the B. subtilis HS25 was 160${\sim}$200 rpm. The optimal culture time for antibacterial activities of the bacterium were shown to be in the range of 12-36 hr.