• Korean Journal of Microbiology
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• v.54 no.4
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• pp.428-435
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• 2018

In this study, we isolated and identified bacteria from freshwater and soil collected from Osang reservoir, to screen antimicrobial bacteria against various pathogenic bacteria. 38 strains were isolated and assigned to the class Proteobacteria (22 strains), Actinobacteria (7 strains), Bacteroidets (6 strains), and Firmicutes (3 strains) based on 16S rRNA gene sequence analysis. Among them, strain OS17 showed a good growth inhibition against 5 methicillin-resistant Staphylococcus aureus subsp. aureus strains and Bacillus cereus, Bacillus subtilis, Filobasidium neoformans. As a result of the 16S rRNA gene sequence analysis, strain OS17 show the high similarity with Burkholderia ambifaria $AMMD^T$, B. diffusa $AM747629^T$, B. tettitorii $LK023503^T$ 99.8%, 99.7%, 99.6%, respectively. We investigated cell growth and antimicrobial activity according to commercial culture medium, temperature, pH for culture optimization of strain OS17. Optimal conditions for growth and antimicrobial activity in strain OS17 were found to be: YPD medium, $35^{\circ}C$ and pH 6.5. When the strain was cultured in LB, NB, TSB, R2A media at $20^{\circ}C$ and $25^{\circ}C$, the antimicrobial activity did not show. Culture filtrate of strain OS17 showed antimicrobial activity against 5 MRSA strains, Bacillus cereus, Bacillus subtilis, and Filobasidium neoformans with inhibition zones from 2 to 8 mm. Optimal reaction time was 48 h in YPD medium, 100 rpm and 0.3 vvm in 2 L-scale fed-batch fermentation process for antimicrobial activity. Culture optimization of strain OS17 can be improved on antimicrobial activity. Therefore, the antimicrobial activity of Burkholderia sp. OS17 had potential as antibiotics for pathogens including MRSA.

• Journal of Life Science
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• v.33 no.4
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• pp.334-342
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• 2023

Forty species of lactic acid bacteria isolated from gajami sikhae were identified as Lactobacillus plantarum, Leuconostoc mesenteroides, Lactobacillus brevis, and Weissella paramesenteroides. 10 of the 40 strains were selected and used for the test. In this study, experiments such as those using acid and artificial gastric juice resistance, bile acid resistance, autoaggregation, coaggregation, and cell surface hydrophobicity were conducted to utilize lactic acid bacteria separated from gajami sikhae as probiotics. The separated lactic acid strains showed high survival rates through displaying resistance to acidic and artificial gastric juices; L. plantarum GS11 showed the best resistance. Also, as a result of a measurement of bile acid resistance, all lactic acid bacteria stocks showed survival of more than 100% with a probiotic number of 10⁸ to 10⁹ log CFU/ml. After evaluating cohesion to indirectly measure cell surface adhesion, autoaggregation ability was shown to be more than 46%. Measurement of xylene adhesion for cell surface hydrophobicity evaluation revealed better cell adhesion than B. subtilis, which has 32.2% hydrophobicity in isolated lactic acid strains. Antibacterial force measurement found antibacterial activity in lactic acid bacteria, excluding L. plantarum GS12 and L. plantarum GS13. Therefore, it was judged that lactic acid bacteria separated from gajami sikhae could be used as probiotics with various probiotic properties.

• Korean Journal of Food Science and Technology
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• v.28 no.2
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• pp.260-266
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• 1996

This study was carried out to investigate the bacterial microflora of commercial and traditional Kochujang. Computer aided idetification systems were used to identify the bacteria in Kochujang. Seven genera such as Bacillus, Corynebacterium, Enterococcus, pasteurella, Pseudomonas, Staphylococcus and Streptococcus in commercial process and 10 genera such as Bacillus, Corynebacterium, Enterococcus, Flavimonas, Flavobacterium, Gemella, Pasteurella, Pseudomonas, Staphylococcus and Streptococcus in traditional process were identified. Distribution of genus Bacillus was $56{\sim}70%$ during fermentation in the commercial process and $38{\sim}50%$ in the traditional process. B. lichenoformis strains identified in this study were classified into three types by their physiological characteristics.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2001.11a
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• pp.61-63
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• 2001

Two experiments were conducted to investigate the feeding influence of wood vinegar and mixed with probiotics on performance and physiological related of broiler chicks for five weeks. Diets contained 21.5%, 3,100kcal/kg and 19.0% CP, 3,100kcal/kg ME for starting and finishing period, respectively. In Expt 1, Four levels of wood vinegar(0, 0.05, 0.10, 0.20%) were fed into two hundred forty chicks with four replicates. In Expt 2, 0, 0.1% wood vinegar(W), 0, 0.1% lactobacillus casei(L) and bacillus subtilis (B) were applied to 2${\times}$2${\times}$2 facotrial design for eight treatments with four replicates. Weight gain, feed intake, feed cholesterol were detected at five weeks old in each experiment. In Expt 1, Weight gain of chicks fed 0.1% wood vinegar(WV) was increased upto 1645.8g, but was not significantly different. However, chicks fed 0.2% WV showed the highest gain and siginificantly different compared to that of control (P＜0.05) for finishing period. Feed intake also showed similar tendency with weight gain. There were no statistical difference in feed conversion. Abdominal fat seemed to be decreased in WV supplemental groups, whereas ND antibody titer tended to increase in those treatments. In Expt 2, 0, 0.1% WV, lactobacillus, bacillus were combined with each other(W$\sub$0/L$\sub$0/B$\sub$0/, W$\sub$0/L$\sub$1/B$\sub$0/, W$\sub$0/L$\sub$0/B$\sub$1/, W$\sub$0/L$\sub$1/B$\sub$1/, W$\sub$1/L$\sub$0/B$\sub$0/, W$\sub$1/L$\sub$1/B$\sub$0/, W$\sub$1/L$\sub$1/ B$\sub$0/, W$\sub$1/L$\sub$0/B$\sub$1/, W$\sub$1/L$\sub$1/B$\sub$1). WV supplemental groups significantly improved feed conversion of all treatments(P＜0.05). There were no interaction in weight gain and feed intake. Total cholesterol was signficantly decreased in WV plus lactobacillus and ladtobacillus plus bacillus treatments. Liver to body ratio(%) of lactobacillus plus WV significantly decreased compared to that of other treatments. The results of these experiments showed that wood vinegar tended to improve the performance of broiler chicks, but was not effect in its combination with lactobacillus or bacillus treatments.

• Food Science and Preservation
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• v.19 no.5
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• pp.757-766
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• 2012

The SSH100-10 bacterial strain, which exhibits strong antifungal (anti-mold and anti-yeast) activity, was isolated from traditional korean soysauce aged 100 years. The strain was identified as Bacillus velezensis based on Gram-staining, the biochemical properties and 16S rRNA gene sequence determination. B. velezensis SSH100-10 showed strong proteinase activity and NaCl tolerance, but did not produce enterotoxin. Two-antifungal compounds from B. velezensis SSH100-10 were purified using SPE, preparative HPLC, and reverse phase-HPLC. The purified antifungal compounds were identified as $C_{14}$ and $C_{15}$ iturin through MALDI-TOF-MS and amino acid composition analysis. The stability characteristics of the antifungal compounds after temperature, pH, and enzyme treatments suggested that B. velezensis SSH100-10 produced more than two antifungal compounds; pH-stable $C_{14}$ iturin A and $C_{15}$ iturin A, and unidentified pH-unstable compounds. The results suggested that B. velezensis SSH100-10 can be used in soybean fermentation as a starter. Moreover it has potential as a biopreservative in the food and feed industry and as a biocontrol agent in the field of agriculture.

• Food Science of Animal Resources
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• v.38 no.4
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• pp.749-758
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• 2018

The objective of this study was to provide preliminary data for food industry by investigating the distribution of microorganisms in raw materials and sausage examining the effect of heating temperature on sausage quality. Total microbes in sausage ranged 2.21-3.11 Log CFU/g. Bacillus pumilus, B. licheniformis, Staphylococcus saprophyticus, and Enterococcus faecalis were detected on sausage. Total microbes in raw materials was 1.59-7.16 Log CFU/g. Different types of microorganisms were found depending on raw materials, with B. pumilus and B. subtilis were being detected in both raw materials and sausage. Total microbes in sausage after heating was in the range of 1.10-2.22 Log CFU/g, showing the trend of decrease in total microbe with increasing heating temperature, although the decrease was not significant. With increasing heating temperature, pH and hardness were also increased. The yield of sausage manufactured at $85^{\circ}C$ was 95.42% while that manufactured at $65^{\circ}C$ was 96.67%. Therefore, decreasing heating temperature during sausage production might increase yield and save energy without microbiological effect.

• Journal of Microbiology and Biotechnology
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• v.20 no.8
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• pp.1210-1214
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• 2010

Many bacteria are involved in the fermentation of doenjang, and Bacillus species are known to perform significant roles. Although SDS-PAGE has been frequently used to classify and identify bacteria in various samples, the microbial diversity in doenjang has not yet been investigated. This study aims to determine the identity and distribution of dominant Bacillus species in doenjang using SDS-PAGE profiles of whole-cell proteins and 16S rRNA gene sequencing. Reference Bacillus strains yielded differential SDS-PAGE banding patterns that could be considered to be highly specific fingerprints. Grouping of bacterial strains isolated from doenjang samples by whole-cell protein patterns was confirmed by analysis of their 16S rRNA gene sequences. B. subtilis was found to be the most dominant strain in most of the samples, whereas B. licheniformis and B. amyloliquefaciens were less frequently found but were also detected in several samples. The results obtained in this study show that a combined identification method using SDS-PAGE profiles of whole-cell proteins and subsequent 16S rRNA gene sequence analysis could successfully identify Bacillus species isolated from doenjang.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.1
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• pp.35-42
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• 2012

We investigated the effect of dietary supplementation with probiotics on growth performance, feed utilization, innate immunity and disease resistance against Streptococcus iniae in juvenile olive flounder Paralichthys olivaceus. Four experimental diets were made by supplementation with three Bacillus sp. probiotics (B. subtilis, B. pumilus and B. licheniformis) into a basal diet (control) at 0.5% each. Three-hundred fish (average BW, 20 g) were randomly distributed (25 per tank) into twelve 150 L capacity polyvinyl circular tanks with three replicates per dietary treatment. Triplicate groups of fish were fed the experimental diets to apparent satiation (twice per day, 09:00 and 17:00 h) for nine weeks. After the feeding trial, a challenge test was directly conducted against S. iniae. The results indicated that dietary supplementation with the probiotic, Bacillus sp, seemed to improve growth performance of olive flounder. Hematological parameters and innate immunity as determined by nitroblue tetrazolium, myeloperoxidase or superoxide dismutase activities were not significantly affected by the probiotic supplementation. The result from the challenge test suggested that dietary supplementation with probiotics Bacillus sp. can improve the disease resistance of olive flounder against S. iniae.

• The Plant Pathology Journal
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• v.32 no.3
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• pp.216-227
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• 2016

Biological control agents (BCAs) from different microbial taxa are increasingly used to control bacterial wilt caused by Ralstonia solanacearum. However, a quantitative research synthesis has not been conducted on the role of BCAs in disease suppression. Therefore, the present study aimed to meta-analyze the impacts of BCAs on both Ralstonia wilt disease suppression and plant (host) growth promotion. The analysis showed that the extent of disease suppression by BCAs varied widely among studies, with effect size (log response ratio) ranging from -2.84 to 2.13. The disease incidence and severity were significantly decreased on average by 53.7% and 49.3%, respectively. BCAs inoculation also significantly increased fresh and dry weight by 34.4% and 36.1%, respectively on average. Also, BCAs inoculation significantly increased plant yield by 66%. Mean effect sizes for genus Pseudomonas sp. as BCAs were higher than for genus Bacillus spp. Among antagonists tested, P. fluorescens, P. putida, B. cereus, B. subtilis and B. amyloliquefaciens were found to be more effective in general for disease reduction. Across studies, highest disease control was found for P. fluorescens, annual plants, co-inoculation with more than one BCA, soil drench and greenhouse condition were found to be essential in understanding plant responses to R. solanacearum. Our results suggest that more efforts should be devoted to harnessing the potential beneficial effects of these antagonists, not just for plant growth promoting traits but also in mode of applications, BCAs formulations and their field studies should be considered in the future for R. solanacearum wilt disease suppression.

• YAKHAK HOEJI
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• v.38 no.3
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• pp.293-299
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• 1994

Forty nine clinical isolates of S. aureus showing resistance to erythromycin(EM) were selected from 83 strains isolated recently in Korea. Fourteen strains of S. aureus showing inducible resistance to MLS antibiotics were selected by disc agar diffusion method. Colony hydridization was executed using two MLS inducible resistance genes, ermA and ermC, identified previously from S. aureus as probes. S. aureus 375 and S. aureus 507 whose genes were not homologous to those probes were finally selected. It was confirmed that the resistance genes of S. aureus 375 and S. aureus 507 had no homology with those probes in southern hybridization test using ermA, ermC and ermAM as probes. It was determined that S. aureus 375 had a plasmid whose size was about 35 kb. To know if the plasmid may have the genes related to inducible resistance to MLS antibiotics, it was attempted to transform Bacillus subtillis BR151 and S. aureus RN4220 with the plasmid isolated from S. aureus 375. It was shown that the gene related to inducible resistance to MLS antibiotics did not exist in this plasmid. These results indicate that two clinical isolates of S. aureus showing inducible resistance to MLS antibiotics have novel genes that have no homology with MLS resistance genes identified so far. It is assumed that these genes may exist in chromosomal DNA.