• Microbiology and Biotechnology Letters
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• v.30 no.3
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• pp.223-229
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• 2002

For the research of the natural marine antioxidant, several bacteria were isolated from the coast of jin-Hae in Korea. Among the marine bacteria studied, strain HJ-14, a gram-negative, motile, strait rod, aerobic, and $Na^{+}$ required bacterium showed high activity of 1,1-diphenyl-2-picrylhydrazyl radical scav- enging. The morphological, physiological, and biochemical characteristics of the strain HJ-14 were similar to those of the Alteromonas macleodii ATCC $27126^{T}$ . Thus, it was tentatively identified as Alteromonas sp. HJ-14. The compositions of major fatty acids in cell membrane of Alteromonas sp. HJ-14 were $C_{ 14:0}$ , $ C_{15:0}$ , $C_{16:0}$ and $C_{17:1}$ $_{w8c}$ , which also suggest that it is affiliated with Alteromonas sp. The optimum culture conditions for production of antioxidant materials with Alteromonas sp. HJ-14 were at $25$~$37^{\circ}C$ and pH 6~8. The optimum conditions for the production of antioxidant for carbon, inorganic nitrogen, and sodium chloride sources were 2.5%(w/v) dextrin, 0.5%(w/v) ammonium sulfate, and 2~6%(w/v) sodium chloride, respectively. The hydroxyl radical scavenging ability of Alteromonas sp. HJ-14 broth was 90.03%, which is higher than ascor-bic acid(83.28%) and lower than butylated hydroxyanisole(95.46%) and $\alpha$-tocopherol(97.17%).

• Korean Journal of Microbiology
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• v.51 no.4
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• pp.364-373
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• 2015

As an effort to utilize alginate, 103 bacterial isolates that were positive for the alginate lyase activity were isolated from various clams and seawater samples collected in Incheon coastal area. Among them, 3 strains (M1-2-1, M6-1, and C8-15) were finally selected for further analysis based on their activities at higher levels than others. These isolates were all Gram-negative and rod shaped halophilic bacteria with motility. According to their physiological and biochemical properties as well as DNA sequence of their 16S rRNA genes, M1-2-1 and M6-1 were identified as a member of genus Pseudoalteromonas and C8-15 belonged to genus Vibrio. They exhibited the alginate degrading activity at the maximal level when they were cultured in APY broth for 6-8 h at $25^{\circ}C$. Both their growth and the enzyme activity were greatly enhanced when NaCl was added to the growth medium. The crude alginate lyases from the supernatants of the bacterial cultures showed the highest activity at $45^{\circ}C$ and pH 7.0-8.0. M1-2-1 and M6-1 produced 2.723 and 1.976 g/L of reducing sugar from alginate, respectively, suggesting that they have potential for commercial application.

• Korean Journal of Microbiology
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• v.48 no.2
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• pp.163-170
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• 2012

In order to inhibit the growth of pathogens and degrade biogenic amines during the fermentation of soybean products, an isolate with antimicrobial activity against pathogens and biogenic amine-degrading property was obtained from 83 traditionally fermented soybean products. The morphological and biochemical tests and the phylogenetic relationship among 16S rRNA gene sequences indicated that the isolate named as the strain SCK B11 was most closely related to Bacillus licheniformis. The cell-free supernatant of two day cultures was active against several pathogens including Enterococcus faecalis, Listeria monocytosis, Micrococcus luteus, Pseudomonas aeruginosa, Bacillus cereus, and Staphylococcus aureus. PCR analysis was conducted to determine relatedness to antimicrobial lantibiotics and biosurfactants produced by Bacillus spp., but showed negative for the genes encoding surfactin, lichenysin, and lichenicidine. Electron microscopic observation indicated that the antimicrobial agent seemed to attack the membrane of the pathogens, leaving the ghost or shrunken cells. The strain was found to degrade histamine by 72% and tyramine by 66% in the cooked soybean containing 5.3% of biogenic amine over 10 days of fermentation time. The use of selected strain would be a potential control measure in manufacturing traditionally fermented soybean products that are difficult to control pathogens and biogenic amine levels.

• Weed & Turfgrass Science
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• v.6 no.3
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• pp.212-221
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• 2017

An actinomycetes isolate G-0299 obtained from a forest soil showed strong phytotoxic activity to Digitaria ciliaris. For the foliar application study, the culture filtrate of the isolate G-0299 showed strong herbicidal activity only to D. ciliaris among the 12 monocot and 5 dicot weed species. And herbicidal activity at a concentration of 500, 250, 125 and $62.5{\mu}gmL^{-1}$ of culture filtrate was 100%, 98%, 70% and 40%, respectively. Phytotoxic symptoms of the culture filtrate by foliar application were desiccation and burn-down or bleaching of leaves and finally plant death. And then the herbicidal activity was exhibited only under the light condition. Also, chlorophyll loss of D. ciliaris leaf tissues in the light condition was much higher than in the dark condition and then chlorophyll content decreased 82%, 5%, respectively. In conclusion, our results suggest that soil bacteria, isolate G-0299 could be a good candidate for new bio-herbicide and provide a new lead molecule for a more unique herbicide.

• Journal of Dairy Science and Biotechnology
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• v.30 no.1
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• pp.45-53
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• 2012

Lactobacillus acidophilus isolated from the feces of a 7-day-old breast-fed infant was characterized to examine the scope of its commercial use. Forty-three Lactobacillus strains, which could grow at pH 5.5, were isolated. From these Lactobacillus isolates, 14 Lactobacillus strains were selected, which demonstrated more than 80% viability and homofermentative lactic fermentation. Finally, 9 L. acidophilus strains (NB 201~NB 209) were identified as candidate strains based upon biochemical properties, carbohydrate utilization, and cellular fatty acid composition. L. acidophilus isolates demonstrated a survival rate of more than 80% when exposed to pH 2.5 for 2 h. In particular, L. acidophilus NB 204 showed a strong acid tolerance, with a 71% survival rate even at pH 2.0. L. acidophilus isolates also manifested high bile acid tolerance; more than 87% of the cells survived on agar containing 1% bile extract, except for L. acidophilus NB 206, which showed a 73% survival rate. All L. acidophilus isolates were confirmed to have proteolytic activity; L. acidophilus NB 204 and NB 209 yielded higher levels of TCA-soluble peptides and free amino acids. The ${\beta}$-galactosidase activity of the L. acidophilus isolates was in the range of 1.97~2.45 units/mL.

• Microbiology and Biotechnology Letters
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• v.20 no.4
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• pp.377-383
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• 1992

Seven strains of Bacillus thuringiensis were isolated from soil in Korea and characterized. The isolates were named HL-8, 10, 12, 13, 14, 15 and 16 which produced parasporal crystals and endospores in their cells. The biochemical characteristics of the seven isolates were only minor different in specific chracteristics to the known serotypes of Bacillus thuringiensis. The number of the plasmid DNA elements from the isolates were studied. The computerized molecular weights of the six plasmid elements in the HL-8 and HL-lO strains were from 3.01 to 15.1 Md, four plasmid elements in the HL-12 were from 5.4 to 21.9 Md, four plasmid elements in HL-13 were from 5.1 to 20 Md, three plasmid elements in HL-15 were from 3.4 to 11.3 Md and three plasmid elements in the HL-16 were from 2.4 to 20.1 Md. The seven isolates showed resistances to ampicillin, bacitracin, cephalothin, methicillin and penicillin G. The strains of HL-8, HL-lO, HL12, HL-14, HL-15 and HL-16 showed lethalities against Culex pipiens 3rd instar larvae. The HL8 and 14 strains showed 100% lethality to the larvae within 48 hours. HL-13 strain did not have toxicity against the larvae.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.8
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• pp.1251-1257
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• 2005

This study was carried out to investigate characteristics of acetic acid bacteria for persimmon vinegar fermen-tation. Acetic acid bacteria were isolated from statically fermented vinegar. Microscopically the cells appeared as non-motile and non-flagellated, preferentially occuring in pairs. Isolated strains were able to grow in the presence of acetic acid, ethanol, and glucose. Four of them produced 2-ketogluconic acid but did not produce 5-ketogluconic acid. The four strains isolated from statically fermented vinegar were considered to be grouped into Acetobacter. The strains were inoculated into persimmon juice for persimmon vinegar fermentation. They produced acetic acid in the range of 5.25$\∼$5.68$\%$.

• Korean Journal of Microbiology
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• v.45 no.4
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• pp.339-345
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• 2009

Two lactic acid bacteria (LAB) with high ornithine-producing capacity were isolated from kimchi. Examination of the biochemical features using an API kit indicated that the strains belonged to the members of Weissella genus. They were gram positive, short rod-type bacteria, and able to grow anaerobically with $CO_2$ production. The isolates grew well on MRS broth at $25\sim37^{\circ}C$ and pH of 6.0~7.0. The optimum temperature and pH for growth are $30^{\circ}C$ and pH 6.5. The isolates fermented arabinose, ribose, xylose, glucose but not cellobiose, galactose, raffinose, or trehalsoe. The 16S rDNA sequences of isolates showed 99.6% and 99.7% homology with the Weissella koreensis S5623 16S rDNA (access no. AY035891). They were accordingly identified and named as Weissella koreensis OK1-4 and Weissella koreensis OK1-6, and could produce ornithine from MRS broth supplemented with 1% of arginine at a productivity of 27.01 and 31.41 mg/L/h, respectively. This is the first report on the production of ornithine by the genus Weissella isolated from kimchi.

• Korean Journal of Ecology and Environment
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• v.36 no.2 s.103
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• pp.108-116
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• 2003

To investigate bacteria with algal Iytic activities against Anabaena cylindrica when water blooming occurs and to study enzyme profiles of alga-Iytic bacteria, various bacterial strains were isolated from surface waters and sediments in eutrophic lakes or reservoirs in Korea. Abacterial strain AK-07 was characterized and identified as Acinetobacter johnsonii based on its16S rDNA base sequence. When AK-07 was co-cultivated with A. cylindrica, bacterial cells propagated to $8\;{\times}\;10^8$ cfu $ml^{-1}$ and Iyses algal cells. However, culture filtrates of AK-07 did not exhibit algal Iytic activities. That suggesting the enzymes on the surfaces of the bacterium might be effective algal Iytic agents to cause Iyses of cells. Acinetobacter johnsonii AK-07 exhibited high degradation activities against A. cylindrica, and formed alginase, caseinase, lipase, fucodian hydrolase, and laminarinase. Moreover, glycosidases for example ${\beta}$-galatosidase, ${\beta}$-glucosidase, ${\beta}$-glucosaminidase, and ${\beta}$-xylosidase, which hydrolyzed ${\beta}$-0-glycosidic bonds, were found in cell-free extracts of A. johnsonii AK-07. Other glycosidase such as ${\alpha}$-galctosidases, ${\alpha}$-N-Ac-galctosidases, ${\alpha}$-mannosidases, and ${\alpha}$- L-fuco-sidases, which cleavage ${\alpha}$-0-glycosidic bondsare not detected. In the results, enzyme systemsof A. johnsonii AK-07 were very complex to do-grade cell walls of cyanobacteria. The polysaccharides or peptidoglycans of A. cylindrica maybe hydrolyzed and metabolized to a range of easily utilizable monosaccharides or other low molecular weight organic substances by strain AK-07 of A. johnsonii.

• Korean Journal of Food Science and Technology
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• v.54 no.3
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• pp.306-312
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• 2022

To test bee pollen as an ingredient for heat-processed foods, bee pollen was puffed under heat at various pressures and examined for its physicochemical properties and antioxidant activities. As the puffing intensity increased, the browning index, total reducing capacity, and DPPH radical scavenging activity of the bee pollen increased significantly (p<0.001). This was attributed to the formation of Maillard reaction products during the puffing process. The wheat flour-puff yeot-gangjeong added with puffed bee pollen showed significantly (p<0.01) higher antioxidant activities than its counterpart with raw bee pollen. In addition, the gangjeong retained the physicochemical characteristics of the puffed bee pollen such as color, soluble solids, titratable acidity, and pH. The results showed that the puffed bee pollen could potentially be used as an ingredient in thermally processed foods and retain its superior antioxidant properties.