• Korean Journal of Microbiology
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• v.37 no.4
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• pp.253-258
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• 2001

A Bacillus circulans KCTC3004 $\beta$-1,3-glucanase gene contained in a recombinant plasmid pLM460 derived from subcloning the original recombinant plasmid pLM530 was trasferred into a new shuttle vector plasmid pLMS1180 by ligating linearized DNAs of pLM460 and pUB110. B. subtilis RM125 and B. megaterium ATCC14945 transformed with pLMS1180 produced the $\beta$-1,3-glucanase substantially. Most of the enzyme was produced during the exponential growth period. The maxium activities of the $\beta$-1,3-glucanase produced by the Bacillus transformants were compared with that of the B. circulans gene donor strain. The B. subtilis RM125 (pLM1180) enzyme showed the activity 14 times higher than that of the gene donor cells, followed by the B. megaterium ATCC14945 (pLMS 1180) enzyme with activity 5 times higher than that of the gene donor cells. While E. coli secreted about 7% of the produced enzyme, B. subtilis excreted the enzyme into the medium wholly and B. megaterium about 97% of the total product. The SDS-PAGE of this enzyme produced in E. coli (pLMS1180), B subtilis (pLMS1180) or B. megaterium (pLMS1180) indicated a molecular weight of 38,000. The enzymes overproduced in three different host cells hydrolyzed laminarin to produce mainly laminaribiose, laminaritriose, and laminarioligosaccharides. The plasmid pLMS1180 was stable in B. megaterium, E. coli, but was unstable in B. subtilis.

• Microbiology and Biotechnology Letters
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• v.15 no.2
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• pp.112-115
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• 1987

Optimal pH temperature and sucrose content for the production of vitamin B$_{12}$ and riboflavin by Bacillus megaterium and Enterobacter aerogenes was studied by microbiological analysis. Optimal pH for the production of B$_{12}$ was 6.0 by B. megaterium while the pH for E. aerogenes was 5.0. However, upon the addition of sucrose the optimal pH for B. megaterium shifted to 7.5 but E. aerogenes remained at pH 5.0. In the absence of sucrose, pH did not influence the yields of riboflavin produced by either bacterium. Addition of sucrose stimulated synthesis of riboflavin by both bacteria. Temperature had little effect on the production of vitamins by either bacterium.

• Microbiology and Biotechnology Letters
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• v.31 no.3
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• pp.235-241
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• 2003

For the biological control of Phytophthora blight of red-pepper caused by Phytophthora capsici, an antibiotic-producing plant growth promoting rhizobacteria (PGPR) Bacillus sp. KL 39 was selected from a local soil of Kyongbuk, Korea. The strain KL 39 was identified as Bacillus megaterium by various cultural, biochemical test and API and Microlog system. B. megaterium KL 39 could produce the highest antifungal antibiotic after 40 h of incubation under the optimal medium which was 0.4% fructose, 0.3% yeast extract, and 5 mM KCl at 30 C with initial pH 8.0. The antifungal antibiotic KL 39 was purified by Diaion HP-20 column, silica gel column, Sephadex LH-20 column, and HPLC. Its RF value was confirmed 0.32 by thin-layer chromatography with Ethanol:Ammonia:Water = 8:1:1. The crude antibiotic KL39 was active against a broad range of plant pathogenic fungi, Rhizoctonia solani, Pyricularia oryzae, Monilinia fructicola, Botrytis cinenea, Alteranria kikuchiana, Fusarium oxysporum and Fusarium solani. The purified antifungal antibiotic KL39 had a powerful biocontrol activity against red-pepper phytophthora blight disease with in vivo pot test as well as the strain B. megaterium KL 39.

• Applied Biological Chemistry
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• v.3
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• pp.19-24
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• 1962

The results of re-examination for the isolates D-28, D-28a from Kimchi and 88-3 from laver are summarized as follows: 1). All these isolates were proved to be Gram positive, catalase positive and spore-forming. 2). While these strains were not consistent with Bacillus megaterium group with respect to Voges-Proskauer reaction and methyl red test, their cultural characteristics were well consistent with this group. 3). These isolates showed the similar suger-fermentability as B. megaterium group with a slight difference. 4). It is proved that, according to the forgoing results and vitamin $B_{12}$ producibility, the isolate 88-3 is identical with B. megaterium NRRL-B 938 and D-28, D-28a, with B. megaterium 425-1 and 425-2, respectively.

• Journal of Environmental Science International
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• v.19 no.9
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• pp.1077-1082
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• 2010

This study was performed to investigate the nutritional conditions controlling keratinase activity in Bacillus megaterium F7-1. B. megaterium F7-1 produced keratinase using chicken feather as a sole source of carbon, nitrogen and sulfur. Addition of the feather medium with glucose enhanced keratinase production (68.9 U/ml), compared to control without glucose (63.2 U/ml). The synthesis of keratinase was repressed by addition of $NH_4Cl$ in B. megaterium F7-1. The highest keratinase production (70.9 U/ml) was obtained with the feather medium containing glucose and $MgSO_4{\cdot}7H_2O$. Keratinase was produced in the absence of feather (4.9 U/ml), indicating its constitutive synthesis. Feather degradation resulted in free SH group formation. B. megaterium F7-1 effectively degraded chicken feather meal (86%), whereas duck feather, human nail, human hair and sheep wool displayed relatively low degradation rates (8-34%).

• Korean Journal of Microbiology
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• v.40 no.1
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• pp.43-48
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• 2004

Bacillus megaterium F7-1 producing keratinolytic protease was isolated from decayed chicken feather. The optimal culture conditions for the production of keratinolytic protease by B. megaterium F7-1 were investigated. The composition of optimal medium for the keratinolytic protease was 0.2% glucose, 0.8% skim milk, 0.05% NaCl, 0.01 % $(K_2HPO_4$, 0.02%, $(KH_2PO_4$ and 0.01 % $MgCl_2$. Especially, skim milk was found to be the most effective compound in keratinolytic protease production. The optimal temperature and initial pH were 6.5 and $25^{\circ}C$, respectively. The keratinolytic protease production under optimal condition reached a maximum of 269 U/ml after 5 days of cultivation. B. megaterium F7-1 degraded 98% of the feather used in the optimized medium within 6 days.

• Korean Journal of Food Science and Technology
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• v.22 no.6
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• pp.611-617
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• 1990

This study was conducted to breed a high vitamin $B_{12}$ producer by the fusion of protoplasts between Bacillus natto and Bacillus megaterium. Auxotrophic mutants of Bacillus natto SH-34 ($thr^-try^-rif^r$) and Bacillus megaterium BK-13 ($arg^-ade^-lys^-str^r$) which showed high protease activity and production of vitamin $B_{12}$, respectively, were isolated for the fusion experiment. Protoplasts were induced by incubating the cells with lysis solution containing $500{\mu}/ml$ lysozyme, and the ratio of protoplast and regeneration formation were ranged from 99% and 67%, respectively. Fusion frequencies of fusants between Bacillus natto SH-34 and Bacillus megaterium BK-13 were appeared in the ranges of $1.0{\times}10^{-5}$ under the treatment of 30% PEG 6000 containing 3% PVP. The fusant, MNF-72 showed the highest product yield of $7.85{\mu}g/g-cell\;vitamin\;B_{12}$ in production medium. For the improvement of productivity, the immobilization of fusants with sodium alginate was carried out. In batch and continuous fermentation systems, the productivity were determined to be $0.58{\mu}g/ml.hr\;and\;0.80{\mu}g/ml.hr\;vitamin\;B_{12}$ under optimum condition, respectivity.

• Microbiology and Biotechnology Letters
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• v.30 no.4
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• pp.352-358
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• 2002

An amylase that hydrolyzes starch into maltopentaose as a main product was found in the culture supernatant of a strain of Bacillus megaterium KSM B-404 isolated from local soil. The enzyme was purified 129-fold by ammonium sulfate precipitation, DEAE-Toyopearl and Superdex 75 HR 10/30 column using a FPLC system. The molecular weight of the amylase was determined as about 68 kDa by using SDS-PAGE. Optimum pH and temperature of amylase were found to be $50^{\circ}C$ and pH 6.0~7.0, respectively. The enzyme was stable up to $60^{\circ}C$ by addition of $Ca^{2+}$ and its pH stability was in the range of 6.0~10.0. The activity of enzyme was inhibited by $Cu^{2+}$ $Hg^{2+}$ , and $Fe^{3+}$ and maintained by $Ca^{2+}$ and $Mg^{2+}$ . EDTA and pCMB also showed inhibitory effect to the enzyme. TLC and HPLC analysis of the products of the enzyme reaction showed the presence of maltopentaose(52%), maltotriose (25%), maltose (11%), glucose, and maltotetraose in the starch hydrolysates.

• Mycobiology
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• v.45 no.3
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• pp.213-219
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• 2017

In our previous study, three bacterial strains, Bacillus megaterium KU143, Microbacterium testaceum KU313, and Pseudomonas protegens AS15, were selected as effective biocontrol agents against Aspergillus flavus on stored rice grains. In this study, we evaluated the inhibitory effects of the volatiles produced by the strains on A. flavus growth and aflatoxin production on stored rice grains. The three strains significantly reduced mycelial growth of A. flavus in dual-culture assays compared with the negative control strain, Sphingomonas aquatilis KU408, and an untreated control. Of these tested strains, volatiles produced by B. megaterium KU143 and P. protegens AS15 markedly inhibited mycelial growth, sporulation, and conidial germination of A. flavus on agar medium and suppressed the fungal populations in rice grains. Moreover, volatiles produced by these two strains significantly reduced aflatoxin production in the rice grains by A. flavus. To our knowledge, this is the first report of the suppression of A. flavus aflatoxin production in rice grains using B. megaterium and P. protegens volatiles.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.3
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• pp.403-409
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• 2001

A novel strain of SFO41 producing a large amount of cholesterol oxidase as an extracellular enzyme isolate from Korean salt fermented foods. The strain was identified as Bacillus megaterium based on morphological, cultural and physiological characteristics. Experiments were carried out to optimized the condition of cholesterol oxidase production using B. megaterium SFO41. B. megaterium SFO41 was shown to give the maximum yield of cholesterol oxidase in the medium containing 2.0% glucose, 0.5% yeast extract. 0.03% $MgSO_4{\cdot}7H_2O,\;0.02%\;K_2HPO_4,\;0.2%\;NH_4NO_3$ and 0.2% cholesterol. The optimum culture conditions, temperature, initial pH and agitation speed were $30^{\circ}C$, 7.0 and 150 rpm, respectively. The enzyme production reached a maximum level at 24 hr of cultivation (2.37 U).