• Korean Journal of Food Science and Technology
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• v.22 no.2
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• pp.221-226
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• 1990

Fish flesh of Alaska pollack containing 5% of corn starch were fermented with 8 strains of mold and monitoring of their flavor characteristics, acceptability, nucleotides and their related compounds, amino acid compositions were conducted. All strains were grown vigorously on fish flesh media and formed their characteristic spores with unique flavor by strains. Amino type nitrogen $(NH_2-N)$ content of fermented fish flesh (FFF) were 25-26 times higher than that of raw flesh and 6-15 times higher in extractable nitrogen (Ex-N) content . The strains which produce more ADP (Adenosine 5'-diphosphate) in FFF also showed much higher level of IMP (Inosine 5'-monophosphate) and GMP (Guanosine 5'-monophosphate) content than that of raw flesh. Amino acid composition were differ by strain but lysine was generally highest and arginine, glutamic acid, leucine and alanine in order In review of sensory evaluation , total content of nucleotides, $NH_2-N$, Ex-N and amino acid compositions, suitable strains for fish flesh fermentation were Aspergillus oryzae KFCC 11371, Asp. oryzae KFCC 32343, Penicillium roqueforti KFCC 11269 and Asp. quercinus.

• Korean Journal of Food Science and Technology
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• v.46 no.3
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• pp.328-333
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• 2014

Folate is a water-soluble vitamin B that is required for the synthesis of amino acids and nucleic acids. It plays an important role in cell division and cell growth in several living organisms. The purpose of this study was to screen strong folate-synthesizing bacteria and to optimize their culture conditions for folate production. Folate production was quantified by microbiological assays by using folate-dependent strain Lactobacillus rhamnosus KCTC 3237. Folate derivatives were identified by LC-MS/MS. Of the 65 strains of bifidobacteria and lactobacilli tested, L. plantarum Fol 708 demonstrated the greatest ability to produce folate. Its optimal pH for folate production was 5.5 in a pH-controlled, lab-scale fermenter. Coculturing L. plantarum Fol 708 with L. brevis GABA 100 in a milk medium enhanced the level of folate produced in comparison to culturing L. plantarum Fol 708 alone.

• Applied Biological Chemistry
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• v.32 no.4
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• pp.424-434
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• 1989

The rationale for the use of fungi in treating waste streams from food processing plants I~as been that of incorporating the dissolved and suspending nutrients into a macroscopic organism which can be filtered out readily. In order for a process using fungi to meet these objectives we examined a strain of fungi, Aspergillus fumigatus, which grew well on a variety of polysaccharide-containing materials and showed both efficient BOD removal and high quality protein recovery. In this experiment the fungal choice was based on the laboratory screening studies where the criteria used was BOD and COD reduction, growth response, mycelial yield, and the ability to compete with the natural flora. In the fermentation system used far the continuous culture of Aspergillus fumigatus the best combination of operating variables, inoculum ratio, temperature, initial pH, fermentation time and agitation rate was 5%(v/v), $35{\sim}40^{circ}C,\;pH\;4.5{\sim}5.0$, 2days and 150rpm, respectively. The fungus reduced BOD and COD to 94.0 and 90.4%, respectively and 3.15g of dry mycelium per liter of alcohol waste was harvested during 48hr of incubation time. The protein efficiency ratios for the control diet and the experimental diet containing the fungal protein were $3.42{\pm}0.15$ and $3.40{\pm}0.43$, respectively.

• Journal of Life Science
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• v.27 no.10
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• pp.1161-1167
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• 2017

In order to find a new antimicrobial bacterium, we performed screening for antimicrobial activity of bacteria isolated from the eggs of a sea hare. The newly identified strain was designated as Phaeobacter inhibens KJ-2, based on the biochemical characterization and 16S rRNA gene sequence analysis. A colony of P. inhibens KJ-2 showed a circular and ruler-like smooth form at the edge, and a brown color. However, when maintained with a longer incubation time, its coloring was transformed into dark brown. From the result of SEM, P. inhibens KJ-2 is a bacillus which has a length of $0.8{\sim}1.0{\mu}m$ and a width of $0.4{\sim}0.6{\mu}m$. The optimal growth and antimicrobial activity were observed by shaking the culture for 24 hr at $20^{\circ}C$, which showed potent activity against pathogenic bacteria including Vibrio logei, Vibrio campbellii, Vibrio mimicus, Vibrio vulnificus, and Vibrio salmonicida. The antimicrobial activity was proportional to the amount of produced acylated homoserine lactones (AHLs). Therefore, we suggest that production of antimicrobial materials from P. inhibens KJ-2 is regulated by Quorum sensing (QS).

• Journal of Chitin and Chitosan
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• v.23 no.4
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• pp.228-233
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• 2018

We isolated microorganisms from soil, which is sampled at forest, Kyeonbuk, Korea, as cellulolytic microorganisms. The isolated strains were identified by analysis of 16S rRNA gene from the starins. The result, four kinds of Bacillus subtilis, one kind of Bacillus amyloliquefaciens, and one kind of Bacillus cereus were identified. Among these strains, Bacillus subtilis was selected due to its high cellulase activity and this strain was named as Bacillus subtilis CNS. The optimum pH and temperature of the cellulase from Bacillus subtilis CNS was pH 5.0 and $40^{\circ}C$, respectively. In the investigation of pH and temperature stability, the cellulase from Bacillus subtilis NSC stabled pH 4.0~6.0 range and until $40^{\circ}C$ for 30 min perfectly. In the enzyme activity for various cellulosic substrate, cellulase from Bacillus subtilis CNS showed the highest activity for CM-cellulose. And, the enzyme activities for alkali swollen cellulose, Alpha-cellulose, Sigmacell-cellulose, and Avicel were approximately 31%, 8%, 8% and 4% of activity for CM-cellulose, respectively. In the degradation of CM-cellulose, the 0.26 U/ml and 0.52 U/ml of cellulase showed 0.43 and 0.76 U/ml activity for CM-cellulose after the reaction of 120 min, respectively.

• Research in Plant Disease
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• v.19 no.4
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• pp.254-258
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• 2013

Fusaric acid (FA) is a mycotoxin produced by Fusarium species. Its toxicity is relatively low but often associated with other mycotoxins, thus enhancing total toxicity. To date, biosynthetic genes or enzymes for FA have not been identified in F. oxysporum. In order to explore the genetic element(s) for FA biosynthesis, restriction enzyme mediated integration (REMI) procedure as an insertional mutagenesis was employed using FA producing-F. oxysporum strains. Genetic transformation of two F. oxysporum strains by REMI yielded more than 7,100 transformants with efficiency of average 3.2 transformants/${\mu}g$ DNA. To develop a screening system using phytotoxicity of FA, eleven various grains and vegetable seeds were tested for germination in cultures containing FA: Kimchi cabbage seed was selected as the most sensitive host. Screening for FA non-producer of F. oxysporum was done by growing each fungal REMI transformant in Czapek-Dox broth for 3 weeks at $25^{\circ}C$ then observing if the Kimchi cabbage seeds germinated in the culture filtrate. Of more than 5,000 REMI transformants screened, fifty-three made the seeds germinated, indicating that they produced little or fewer FA. Among them, twenty-six were analyzed for FA production by HPLC and two turned out to produce less than 1% of FA produced by a wild type strain. Sequencing of genomic DNA regions (252 bp) flanking the vector insertion site revealed an uncharacterized genomic region homologous (93%) to the F. fujikuroi genome. Further study is necessary to determine if the vector insertion sites in FA-deficient mutants are associated with FA production.

• Korean Journal of Environmental Biology
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• v.34 no.4
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• pp.304-313
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• 2016

One of the issues currently facing nuclear power plants is how to store spent nuclear waste materials which are contaminated with radionuclides such as $^{134}Cs$, $^{135}Cs$, and $^{137}Cs$. Bioremediation processes may offer a potent method of cleaning up radioactive cesium. However, there have only been limited reports on $Cs^+$ tolerant bacteria. In this study, we report the isolation and identification of $Cs^+$ tolerant bacteria in environmental soil and sediment. The resistant $Cs^+$ isolates were screened from enrichment cultures in R2A medium supplemented with 100 mM CsCl for 72 h, followed by microbial community analysis based on sequencing analysis from 16S rRNA gene clone libraries(NCBI's BlastN). The dominant Bacillus anthracis Roh-1 and B. cereus Roh-2 were successfully isolated from the cesium enrichment culture. Importantly, B. cereus Roh-2 is resistant to 30% more $Cs^+$ than is B. anthracis Roh-1 when treated with 50 mM CsCl. Growth experiments clearly demonstrated that the isolate had a higher tolerance to $Cs^+$. In addition, we investigated the adsorption of $0.2mg\;L^{-1}$ $Cs^+$ using B. anthracis Roh-1. The maximum $Cs^+$ biosorption capacity of B. anthracis Roh-1 was $2.01mg\;g^{-1}$ at pH 10. Thus, we show that $Cs^+$ tolerant bacterial isolates could be used for bioremediation of contaminated environments.

• Korean Journal of Microbiology
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• v.49 no.2
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• pp.131-136
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• 2013

This study was conducted to select rhizobia from hairy vetch (Vicia villosa Roth) with nodulation and excellent nitrogen-fixing ability. Hairy vetch root was collected from 7 of cultivation region of all over the country, rhizobia were isolated from the root nodules. Isolates were re-inoculated into a hairy vetch separately and studied nodulation and nitrogen-fixing ability. As a result, total of 52 Rhizobium isolates were isolated from the hairy vetch root nodules, among these, 16 isolates were Rhizobium which show good growth at more than 0.5% NaCl concentration. These 16 isolates were re-inoculated separately, 8 weeks after, good root nodule formation was observed from Rhizobium sp. RH1, RH3, RH81, RH82, RH84, and RH93 strain treated samples. Six isolates were positive for nitrogen fixing ability, the highest acetylene reduction activity was shown by Rhizobium sp. RH84. Results suggest that the Rhizobium sp. RH84 could be used as the possibility of its application as a green manure crop of hairy vetches in nonuniform salt distribution reclaimed land.

• Korean Journal of Microbiology
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• v.45 no.1
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• pp.58-62
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• 2009

From the course of screening of useful enzyme producing microorganism from marine sedimentary layer, we isolated 2 lipase producing strains and their lipase producing activities were tested. 16S rDNA sequence analysis showed that they were Gram-positive bacteria grouped on Janibacter sp. An excellent lipase producing strain, Janibacter sp. LI-68 and J. sp. LI-80 identified by 16S rDNA analysis and biochemical methods (BIOLOG), was further studied its lipase producing characteristics. The optimum initial pH, temperature and the optimum cultral time for the enzyme production on MA medium were 8, $30{\sim}40^{\circ}C$ and 96 h, respectively.

• Journal of Life Science
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• v.17 no.7 s.87
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• pp.970-975
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• 2007

For the screening of ${\gamma}-aminobutyric$ acid (CABA)-producing bacteria, 86 bacterial strains which produce GABA were isolated from Kimchi and Salted fisk .Among these, three strains designated AML15, AML45-1, AML72 with relatively high GABA productivity were selecled by thin layer chromatography (TLC). To elucidate the relationship between isolated strains and the genus Lactobacillus, their 16S rDNA sequence were examined. The result of their DNA sequences showed 99% similarity with Lactobacillus brevis ATCC 367. On the basis of the these results, isolated strains were identified as Lactobacillus brevis and designated L. brevis AML15. In order to determine the optimum conditions for GABA production, the isolated strains were cultivated in pyridoxal phosphate (PLP) and monosodium glutami. acid (MSG). Results showed that L. brevis AML15 had the highest CABA productivity with 10,424 $nM/{\mu}l$ concentration in MRS broth containing 5% (w/v) MSG and 10 ${\mu}M$ PLP at pH 5.0. The results imply that L. brevis AML15 has the potential to be developed as a strain for GABA hyper-production.