• Applied Biological Chemistry
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• 제29권4호
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• pp.422-428
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• 1986

The bacteria were isolated from ordinary Korean soy sauce and soybean Paste. After isolation, we investigated the bacteria which produces the characteristic flavor of ordinary Korean soy sauce and soybean paste, nothing the aroma, presence of amino acids, and free sugars. The results were obtained as follows. The bacteria isolated from ordinary Korean soy sauce and soybean paste were various Bacillus species. The isolated bacteria produced characteristic orders: 'Meju' order, the characteristic saline odor of ordinary Korean soy sauce or ordinary Korean soybean paste order, and enzymes: protease and amylase. The good characteristic saline odor of ordinary Korean soy sauce was produced by Bacillus licheniformis$(SSB_3)$. The good odor of ordinary Korean soybean paste was produced by Bacillus polymyxa$(SSB_4)$, Bacillus species$(SPB_1)$, Bacillus brevis$(SPC_2)$, and Bacillus lichniformis$(SPC_{2-1})$.

• Mycobiology
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• 제47권3호
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• pp.335-339
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• 2019

Endophytic fungi have the ability to live inside the host plant tissues without causing neither symptoms of diseases/or harm. Opportunistic infections are accountable for majority of the outbreaks, thereby putting a burden on the health system. To investigate and characterize the bioactive compounds for the control of bacteria of clinical importance, extracts from endophytic fungi were isolated from indigenous South African medicinal plants. Extracts from endophytic fungi were isolated from 133 fungal strains and screened against Gram positive and negative bacteria namely Bacillus cereus, Escherichia coli, Enterococcus faecium, and E. gallinarum using disk diffusion. Furthermore, gas chromatography-mass spectrometry was performed to identify the bioactive compounds. Sixteen out of one hundred and thirty-three (12%) fungi extracts exhibited antibacterial properties against some of the selected bacteria. E. coli was found to be the most susceptible in contrast to E. faecium and E. gallinarum which were the most resistant. The isolate MHE 68, identified as Alternaria sp. displayed the greater spectrum of antibacterial activities by controlling selected clinical bacteria strains including resistant E. faecium and E. gallinarum. The chemical analysis of the extract from MHE 68 indicated that linoleic acid (9,12-octadecadienoic acid (Z,Z)) and cyclodecasiloxane could be accountable for the antibacterial activity. This is the first study conducted on the secondary metabolites produced by endophytic fungal strains isolated from the Pelargonium sidoides DC. possessing antibacterial properties.

• Journal of Korean Society of Water and Wastewater
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• 제20권1호
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• pp.44-52
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• 2006

Bio-filtration processes using honeycomb tubes (process 1) and aeration and manganese-sand filtration (process 2) were evaluated for the biological manganese removal efficiency. The concentration of manganese at effluent was stabilized after 20days operation in process 1. It was estimated the required time for attaching and growing microorganisms to honeycomb tubes. In long term of operation periods, manganese removal efficiency was dropped for the excessively attached biofilm and manganese dioxide to honeycomb tubes. It took several days for normal operation in process 2, after that manganese removal efficiency was increased to 98% and stabilized for 1.5 years. Microorganisms in process 1 and 2 were isolated and cultured to characterize manganese-oxidizing bacteria. Among the four types of colony, light brown colony was turned blue color by leuco crystal violet spot test. Stenotropomonas genus, known as manganese-oxidizing bacteria, was identified by 16S rDNA partial sequencing analysis which was isolated in process 1 and 2. For the biological treatment to remove manganese, these two considerations are important. One is to choose the proper media attaching manganese oxidant, another one is to define the cultural condition of isolated manganese-oxidizing bacteria.

• Journal of the Korean Society of Food Science and Nutrition
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• 제27권6호
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• pp.1059-1064
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• 1998

Fermented beverage using lactic acid bacteria isolated from kimchi was investigated. Lactic acid bacteria KL 1, KD 6, KL 4 strains from kimchi, or obtained Lactobacillus acidophilus, Lactobacillus plantarum, Leuconostoc mesenteroides with and without yeast(Saccharomyces cerevisiae) were inoculated in fruit vegetable juice for single and mixed culture fermentation. During the fermentation by bacterial strain and yeast for 1~3 days at 30oC, various fermentation behaviors were observed. The growth rate of mixed culture of KL 1 and yeast was higher than that of single culture by KL 1 alone during the fermentation. The amount of organic acid produced by the mixed culture fermentation of KL 1 and yeast was 0.82%(3 day) or 0.58%(1 day) and with the final pH of 3.3(3 day) or 4.2(1 day). These mixed culture systems of isolated strains or other bacterial strains had almost similar results of growth rate and acid production. Among several bacterial strains, KL 1 was suitable for the mixed culture fermentation with yeast in terms of desirable fermentation behavior and organoleptical quality. The selected strain, KL 1 was identified as Leuconostoc spp. through the series of tests on carbohydrate fermentation and biochemical characteristics.

• Microbiology and Biotechnology Letters
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• 제38권3호
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• pp.302-307
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• 2010

Nitrogen is an element need to grow plants growth. Plants take up nitrogen in the form of nitrate or ammonium. Most of plants absorb nitrogen source as fertilizers. But from 50 to 70% of fertilizers applied were washed away. This study was conducted to isolate free-living nitrogen fixing bacteria from reed and to examine its beneficial traits for developing sustainable biofertilizers. Enriched consortium obtained from a reed in Ansan was developed for the fixing of nitrogen. Nitrogen fixing bacteria isolated from an enriched culture in Congo Red Medium was analyzed by 16s rDNA sequencing. AKC-10 was isolated and shown to have excellent nitrogen fixing ability. The optimum conditions of nitrogen fixing ability were $25^{\circ}C$ ($237.50{\pm}39.65\;nmole{\cdot}mg-protein^{-1}{\cdot}h^{-1}$ and pH 7 ($168.335{\pm}12.84$ nmole/hr mg-protein). It was identified as Microbacterium hominis [(AKC-10 (similarity : 99%)]. This strain was had to IAA (indole-3-acetic acid) productivity and ACC(1-aminocyclopropane-1-carboxylic acid) deaminase activity. Therefore, Microbacterium hominis AKC-10 stimulated plant development in the soil, enhancing the efficiency of remediation.

• Korean Journal of Fisheries and Aquatic Sciences
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• 제51권4호
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• pp.397-403
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• 2018

We determined the resistance rates of pathogenic bacteria isolated from cultured olive flounder Paralichthys olivaceus to erythromycin (Em), antibiotic typically used in aquaculture and analyzed the genotypes of resistant bacteria using polymerase chain reaction (PCR). We isolated and utilized 160 isolates of Streptococcus parauberis, 1 of S. iniae, 66 of Edwardsiella tarda, 56 of Vibrio sp. and 23 of unidentified bacteria from presumed infected olive flounder from Jeju Island from March 2016 to October 2017. Of the 306 isolated strains, Em-resistant strains included 33 of S. parauberis, 39 of E. tarda and 2 of Vibrio sp. We conducted PCR to assess the resistance determination of Em-resistant strains. Five different types of Em-resistance genes were detected in the 74 Em-resistant strains: erm (A), erm (B), erm (C), mef (A) and mef (E); erm (A) and erm (B) were detected in 1 (3%) and 24 (72.7%) S. parauberis isolates, respectively. In E. tarda, erm (B) was detected in five isolates (12.8 %) and no Em-resistance genes were detected in the two Vibrio sp. isolates.

• Journal of Microbiology
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• 제43권1호
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• pp.1-10
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• 2005

We isolated and cultured bacteria inhabiting solar saltern ponds in Taean-Gun, Chungnam Province, Korea. All of the isolated 64 strains were found to be moderately halophilic bacteria, growing in a salt range of 2-20 %, with an optimal concentration of 5% salt. Bacterial diversity among the isolated halophiles was evaluated via RFLP analyses of PCR-amplified 16S rDNAs, followed by phylogenetic analysis of the partial 16S rDNA sequences. The combination of restriction enzyme digestions with HaeIII, CfoI, MspI and RsaI generated 54 distinct patterns. A neighbor-joining tree of the partial 16S rDNA sequences resulted in the division of the 64 strains into 2 major groups, 45 strains of ${\gamma}-Proteobacteria$ (70.3%) and 19 strains of Firmicutes (29.7%). The ${\alpha}-Proteobacteria$ and Cytophaga-Flavobacterium-Bacterioides groups, which were repeatedly found to exist in thalassohaline environments, were not represented in our isolates. The ${\gamma}-Proteobacteria$ group consisted of several subgroups of the Vibrionaceae (37.5%), Pseudoalteromonadaceae (10.9%), Halomonadaceae (7.8%), Alteromonadaceae (7.8%), and Idiomarinaceae (6.3%). Members of Salinivibrio costicola (29.7%) were the most predominant species among all of the isolates, followed by Halobacillus treperi (12.5%). Additionally, three new species candidates were found, based on similarities of the 16S rDNA sequences to those of previously published species.

• Environmental Engineering Research
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• 제15권1호
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• pp.15-21
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• 2010

This study was conducted to evaluated seawater bacteria and their seasonal characteristics in the arsenic contaminated coastal seawater of Yeosu Bay, the Republic of Korea. Arsenite-oxidizing bacteria play an important role in the seawater of the arsenic contaminated bay, with a variety of arsenic resistance system (ars) genotypes being present during summer. Specifically, Bacillus sp. strain SeaH-As22w (FJ607342), isolated from the bay, were found to contain the arsB, arrA and aoxR type operons, which are involved in arsenic resistance. The isolated bacteria showed relatively high tolerance to sodium arsenite (III; $NaAsO_2$) at concentrations as high as 50 mM. Additionally, batch seawater experiments showed that Bacillus sp. strain SeaH-As22w completely oxidized 1 mM of As (III) to As (V) within 10 days. Ecologically, the arsenic-oxidizing potential plays an important role in arsenic toxicity and mobility in As-contaminated coastal seawater of Yeosu Bay during all seasons because it facilitates the activity of Bacillus sp. groups.

• Korean Journal of Veterinary Research
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• 제51권1호
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• pp.29-35
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• 2011

Lack of hygiene and puerperal mastitis are common causes of bacterial diseases in nursing neonates. The aim of this study was to isolate microorganisms from milk samples of healthy female Jindo dogs with suckling puppies and to investigate antimicrobial susceptibility against the isolated bacteria. Milk samples were collected from 120 udders of 12 lactating Jindo dogs that were 2~4 years old without any clinical diseases including mastitis. Bacteria were isolated from 64 milk samples (53.3%), either singly (76.6%) or in combination (23.4%). Staphylococcus (S.) spp. was the most common microorganisms (74.7%) isolated from canine milk, followed by Haemophillus spp. (10.9%), Streptococcus spp. (9.6%), Gardnerella spp. (2.4%) and Moraxella spp. (2.4%). The most frequently isolated organism was S. warneri (31.3%). Antimicrobial susceptibility of these bacteria was tested with 17 antimicrobial agents by Kirbyand Bauer standardized disc diffusion method. Results indicated that bacteria isolated from healthy canine milk were mostly susceptible to amoxicillin-clavulanic acid, cephalothin and ceftiofur, but were resistant to erythromycin, neomycin and tetracycline.

• Journal of Technologic Dentistry
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• 제22권1호
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• pp.145-152
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• 2000

In order to select an effective antibiotic substance against oral resident bacteria, we were isolated from soil and texonomically analyzed. Seven hundred and eighteen strains were isolated on humic acid- vitamin agar(HV agar) and 220 strains were on methanol medium from three each paddy forest, field and riverside soil samples. So, during the screening of antibiotics from soil, we isolated microorganisms showing powerful antagonistic activity against oral resident bacteria. Microorganism was tested against 25 strains of bacteria, yeast and fungi. Among them, No. 248 strain exhibited the most strongly growth inhibition. So, the taxonomical analysis the isolated strain was found to be unknown Actinomyces sp. and was named No 248. A production of the antibiotics from No. 248 begins at the early exponential phase developed at the 72th hour under the optinum conditions. The property of No. 248 antimicrobial compound was very stable under acid(pH 3.0) and alkali(pH 10.0) treatment, but it was instable in heat treatment at $120^{\circ}C$. For the improvement of antibiotic activity, two mutants were isolated from strain No. 248 by the treatment of mutagenic agents, NTG and hydroxylamine. As a result, the mutant strains excreted the potent antibiotics to inhibit the growth of Candida albicans.