• Proceedings of the Plant Resources Society of Korea Conference
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• 2010.05a
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• pp.6-6
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• 2010

Bacteria of the Bacillus sp. are well known to possess antagonistic activity against numerous plant pathogens. In the present study, 11 Bacillus sp. were isolated from the brackish environment and assayed for antagonistic activity under in vitro and in vivo conditions. Among the 11 isolates tested, 9 isolates effectively inhibited the growth of various plant pathogens, namely Phytophthora capsici, Phytophthora citropthora, Phytophthora citricola, Phytophthora sojae, Colletotricum coccodes, Colletotricum gloeosporioides, Colletotricum acutatum, Rhizoctonia solani, Fusarium solani, Fusarium graminearum, Pyricularia sp. and Monilina sp. The effective isolates were further screened for Phytophthora blight suppression in Capsicum annuum L. under green house conditions. The isolate SB10 exhibited the maximum (72.2%) reduction in disease severity. The antifungal compounds from the isolate were isolated and characterized. The isolated compounds exhibited high thermo stability ($100^{\circ}C$ for 30 min). Matrix-Assisted Laser Desorption Ionization-Time of Flight investigation of the antifungal compounds revealed three lipopeptide complexes, the surfactins, the iturins, and the fengycins.

• Journal of Life Science
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• v.9 no.5
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• pp.510-517
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• 1999

For the treatment of Korean food-wastes, three mesophilic and one thermophilic bacteria were isolated from soil and fermented fertilizers. The thermophilic Streptomyces sp. strain WF021 produced two enzymes which were a protease and a lipase at 55$^{\circ}C$. The mesophilic Bacillus sp. strain WF024 produced four enzymes which were a protease, a lipase, a amylase and a cellulase when the strain was grown both at 3$0^{\circ}C$ and 55$^{\circ}C$. The Bacillus sp. PY123 had produced three enzymes which were a protease, a cellulase and a lipase at 3$0^{\circ}C$. The Bacillus sp. strain CM1 produced three enzymes which were a protease, a amylase, and a cellulase at 3$0^{\circ}C$. The bacteria were grown in media containing 6% NaCl at least and did not have antagonism each other. The four isolates treated much more food-wastes than referance strains did. In a flask without aeration, three reference strains treated 15.4% of food-wastes, while four isolates treated 23.7% of food-wastes. In a flask with aeration, food-wastes were treated 67.3% by four isolates, and 64.3% by three reference strains, but 53.9% without bacteria. However, food-wastes were treated about 78% in a 200$\ell$-reactor made by Siwon Co., while 65.8% in a 20$\ell$-reactor made by Sanyo Co.

• The Plant Pathology Journal
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• v.18 no.1
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• pp.36-42
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• 2002

Resistance of perilla varieties to Botrytis cinerea LVF12 was evaluated, while antagonistic bacteria were selected and tested for their efficacy towards biological control of gray mold rot caused by B. cinerea. Among 11 perilla varieties tested for disease resistance, Milyang variety showed some degree of resistance, while the rest of varieties showed no resistance. Among 250 bacterial isolates collected from perilla loaves and rhizosphere of perilla plants, six isolates showed high levels of inhibitory effect on mycelial growth and conidial germination of B. cinerea in in vitro test. Using the pot test in growth chambers these isolates showed high levels of disease suppression, with Nl isolate showing 95.3% of control value and N4 isolate showing 90.8% of control value. Further test was performed to evaluate the two isolates ability for disease prevention and/or disease therapy, and results showed almost 100% of control vague. Isolates Nl and N4 were identified as Bacillus licheniformis and 5. megatepium, respectively, according to Bergey's manual, API 20E and 50CHB test kit, and Transmission electron microscope.

• The Korean Journal of Mycology
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• v.23 no.2 s.73
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• pp.190-195
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• 1995

For the screening of biocontrol agents against red-pepper anthracnose (Colletotrichum gloeosporioides Penz) 248 isolates of bacteria, 51 of fungi and 30 of yeasts were obtained from phyllospere of medicinal plants. Of isolated microorganisms, four bacterial isolates, KB6, KB12, KB13 and KB14 were highly antagonistic to C. gloeosporioides than the others through dual culture test on potato dextrose agar (PDA). Among the four bacterial isolates, culture filtrate of the isolate KB12 showed the highest inhibition of C. gloeosporioides on PDA. The culture filtrates of four isolates controlled anthracnose on the red fruits, but not on the green fruits. In the living bacterial cell test, high control effect was observed both on the red and the green fruits. In the biochemical test, all isolates were identified as Bacillus subtilis.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.6
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• pp.904-912
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• 2015

There is a great deal of research interest regarding substitutes for antibiotics because of various obstacles to the efficacy and use of antibiotics. We isolated and analyzed diversity of microbiota which exhibited antibacterial activity against 23 pathogenic bacteria, to develop alternative agent of antibiotics. By investigating the microbiota from rocks on the seashore, we characterized and obtained various antibacterial material-producing bacteria. Thirty-one isolates belong to four genera and seven species, according to 16S rDNA sequence analysis, showed antibacterial activities against 23 pathogenic bacteria. The Identity of 16S rDNA sequences indicated three species of Bacillus, one species of Paenibacillus, one species of Pseudomonas and two species of Enterobacter. Two isolates were similar to Bacillus aerophilus, four isolates were similar to Bacillus pumilus, seven isolates were similar to Bacillus safensis, 15 isolates were similar to Paenibacillus polymyxa, respectively. In addition, one isolate was similar with Pseudomonas poae, one isolate was similar to Enterobacter asburiae, and one isolate was similar to Enterobacter ludwigii, respectively. Variations of antibacterial activity and level among the same species were indicated the diverse strains of isolates. Vibrio vulnificus showed the highest degree of growth inhibition by 29 isolates. Further studies regarding antibacterial materials and bacteria suggest that development of probiotic strains or alternative agents to antibiotics.

• Microbiology and Biotechnology Letters
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• v.49 no.3
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• pp.432-439
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• 2021

Microbial community plays important roles in the culture environment of mud crab Scylla serrata. One of the environmental management efforts for the cultivation of S.serrata is by stabilizing microorganisms involved in nitrogen cycle process. The availability of dissolved inorganic nitrogen in its culture environment under a recirculating system closely relates to the nitrogen cycle, which involves both anaerobic and aerobic bacterial activities. Anaerobically, there are two major nitrogen compound degradation processes, i.e., denitrification and dissimilatory nitrate reduction to ammonium (DNRA). This study aimed to identify denitrifying and DNRA bacteria isolated from the recirculating cultivation of S. serrata. The water samples were collected from anaerobic filters called close filter system, which is anaerobically conditioned with the addition of varying physical filter materials in the recirculating mud crab cultures. The results showed that three denitrifying bacterial isolates and seven DNRA bacterial isolates were successfully identified. The phylogenetic analysis based on 16S rRNA gene of the denitrifying bacteria revealed that HIB_7a had the closest similarity to Stenotrophomonas daejeonensis strain MJ03. Meanwhile, DNRA bacterial isolate of HIB_92 showed a 100% similarity to Bacillus sonorensis strain N3, Bacillus vallismortis strain VITS-17, Bacillus tequlensis strain TY5, Geobacillus sp. strain DB24, Bacillus subtilis strain A1, and Bacillus mojavensis strain SSRAI21. This study provides basic information denitrifying and DNRA bacterial isolates identity which might have the potential to be applied as probiotics in aquaculture systems in order to maintain optimal environmental conditions.

• Journal of Applied Biological Chemistry
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• v.61 no.1
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• pp.59-67
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• 2018

This study was conducted to isolate the cellulolytic bacteria able to grow on LB- Carboxymethyl cellulose (CMC) agar trypan blue medium from the mixed forest and Larix leptolepis stands. Three bacterial strains with high activity against both CMC and xylan were isolated. Both API kit test and 16S rRNA gene sequence analysis revealed that the three different isolates belong to the gene Bacillus. Therefore, the isolates named as Bacillus sp. EFL1, Bacillus sp. EFL2, and Bacillus sp. EFP3. The optimum growth temperature of Bacillus sp. EFL1, EFL2, and EFP3 were $37^{\circ}C$. The optimum temperature for CMCase and xylanase from Bacillus sp. EFL1 were $50^{\circ}C$. The optimum pH of Bacillus sp. EFL1 xylanase was pH 5.0 but the optimum pH of CMCase from Bacillus sp. EFL1 was pH 6.0. The optimum temperature of CMCase and xylanase from Bacillus sp. EFL2 was $60^{\circ}C$, respectively. The optimum pH of CMCase of Bacillus sp. EFL2 was 5.0, whereas xylanase showed high activity at pH 3.0-9.0. The optimum temperature for CMCase and xylanase of Bacillus sp. EFP3 was $50^{\circ}C$. The optimum pH for CMCase and xylanse was 5.0 and 4.0, respectively. CMCases from Bacillus sp. EFL1, EFL2, and EFP3 were thermally unstable. Although xylanase from Bacillus sp. EFL1 and EFP3 showed to be thermally unstable, xylanase from Bacillus sp. EFL2 showed to be thermally stable. Therefore, Bacillus sp. EFL2 has great potential for animal feed, biofuels, and food industry applications.

• Applied Biological Chemistry
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• v.51 no.4
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• pp.263-268
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• 2008

Seventy-one Bacillus cereus strains (12 references and 59 food isolates) were analyzed for the occurrence of five different enterotoxin genes (nheABC, hblCDA, entFM, cytK, and bceT) and one emetic toxin cereulide synthetase gene (ces) by PCR (polymerase chain reaction). PCR analysis revealed eight toxigenic patterns in all B. cereus strains tested; they all carried both entFM and nheABC. The presence of hblCDA, cytK, and bceT varied according to the enterotoxin-producing strains, among which hblCDA was the least frequently detected in the food-isolated strains. Only five B. cereus strains harbored ces, associated with the emetic type of food poisoning; however, these strains were devoid of hblCDA, cytK, and bceT.

• Journal of Microbiology
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• v.40 no.2
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• pp.104-108
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• 2002

The hazelnut leaf holer (Anoplus roboris Sufr,, Coleoptera: Curculionidae) is a devastating pest of hazelnut and oak trees. It causes approximately 20-30% economic damage to hazelnut production per year in Turkey. In the present study, in order to fond a more effective and safe biological control agent against A. roboris, we investigated the bacterial flora of the hazelnut leave holer, and tested them for insecticidal effects on it. According to morphological, physiological and biochemical tests bacterial flora were identified as Bacillus circulans (Ar1), Bacillus polymyxa (Ar2), Enterobacter sp. (Ar3) and Bacillus sphaelicus (Ar4). Insecticidal effects of bacterial isolates were performed on adult A. roboris. The highest insecticidal effect determined was 67% by B. sphaericus within eight days. The insecticidal effects of the other isolates (Ar1, Ar2 and Ar3) were determined as 33%, 47% and 47% within the same period, respectively.

• Journal of Life Science
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• v.9 no.1
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• pp.1-7
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• 1999

To isolate of antagonistic bacteria to Phytophthora capsici, which cause Phytophthora blight in red pepper, 237 isolates of Pseudomonas spp. and 260 isolates of Bacillus spp. were screened in selective media from rhizosphere soils of red pepper at Kyongsan, Kyongju, Yongchon and Euisung in Kyongbuk. Among total 497 isolates, 8 isolates of Pseudomonas spp and 4 isolates of Bacillus spp. inhibited the mycelial growth of Phytophthora capsici above 50$\%$ . These antagonistic bacteria showed more inhibitory effect on TSA (tryptic soy agar) than V-8 juice agar. Four isolates, P0704, P1201, B1101 and B1901, showing the most prominent antagonistic activity were selected and identified as P. cepacia (P0704, P1201), B. polymyxa (B1101) and B. subtilis (B1901), respectively. Cell free filtrates of these isolates were shown to inhibit zoosporangia germination and mycelial growth of p. capsici indicating that these isolates turned out to be bacteria producing antifungal substances. As a result of antagonistic test to Phytophthora blight in green house p. cepacia (P0704) showed the highest antagonistic effect with 46.7$\%$ and the rest of them were in the range of 13.4$\%$ to 26.7$\%$ .