• Microbiology and Biotechnology Letters
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• v.17 no.4
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• pp.385-391
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• 1989

D-Glucose isomerase (D-xylose ketol isomerase, EC 5.3.1.5) was purified from the Alkalophilic Bacillus sp. No. 1911 by ammonium sulfate precipitation, DEAE-cellulose ion exchange chromatography followed by Sephadex G-150 gel filtration chromatography. Molecular weight of the purified enzyme was estimated to be 11, 000 by gel filtration on Sephadex G-200, and SDS-polyacrylamide gel electrophoresis showed that the enzyme consisted of four identical or similar subunits with a molecular weight of 43, 000. The enzyme was the most active at pH 7.5 and $65^{\circ}C$, and stable up to 7$0^{\circ}C$ at pH 7.5 and in the range of pH 6-9 at 6$0^{\circ}C$ by 30 min incubation in the presence of Co$^{++}$.

• Microbiology and Biotechnology Letters
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• v.23 no.6
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• pp.710-716
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• 1995

$\beta $-1, 4-D-arabinogalactanase isolated from alkalophilic Bacillus sp. HJ-12, approximate Mw 42 kDa, was generally stable in the range of pH 6-10 and below 50$\circ$C and its highest activity was observed at 60$\circ$C with pH 7-9. The isolated $\beta $-1, 4-D-arabinogalactanase specifically hydrolyzed $\beta $-1, 4-galactosyl linkage that is the major structure of soybean arabinogalactan (SAG) but not $\beta $-1, 3-galactosyl linkage of the other polysaccharides. K. was estimated as 0.67 mg/ml by the method of Hanes-Woolf plot. No metals and chemical reagents inhibited the enzyme activity but urea did. The active site of this enzyme assumed to be tryptophan residue. The hydrolysis products from SAG, assayed by gel chromatography, TLC and HPLC, were predominantly galactotetraose (Gal$_{4}$) and triose (Gal$_{3}$) with a small portion. $\beta $-1, 4-D-arabinogalactanase hydrolyzed ONPG as well as SAG, and the degree of hydrolysis of SAG was 15% which is lower than that by the other $\beta $-1, 4-galactanases from different sources. SAG treated with this enzyme resulted in the reduction of specific viscosity up to 70%.

• Korean Journal of Microbiology
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• v.49 no.1
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• pp.38-45
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• 2013

In this study, euryhaline marine microorganism, Bacillus sp. strain EBW4 isolated from polychaete (Perinereis aibuhitensis) of Suncheon Bay was physiologically, biochemically and genetically characterized. Based on 16S rRNA sequence, EBW14 was found to share 98.25% similarity with Bacillus hemicentroti $JSM076093^T$, 97.96% similarity with Bacillus hwajinponensis SW-$72^T$ and 96.28% similarity with B. algicoa $KMM3737^T$, respectively. The temperature range for the growth of strain EBW4 was $4-40^{\circ}C$, NaCl concentration range 0-17% and pH range pH 5-9, revealing that EBW4 was euryhaline bacterium. Major fatty acids in strain EBW4 were composed of anteiso $C_{15:0}$ (48.2%), iso $C_{16:0}$ (12.1%), anteiso $C_{17:0}$ (11.6%) and iso $C_{14:0}$ (9.4%). EBW4 was found to have DNase, amylase, protease and lipase for the degradation of macromolecules such as DNA, carbohydrates, proteins, lipids, etc. The enzyme activities of alkaline phosphatase, esterase (C4), leucine arylamidase and ${\alpha}$-chymotrypsin were also found in strain EBW4. Analysis of the biodegradation ability of EBW4 for organic hydrocarbons under different salinity conditions using synthetic water waste revealed that EBW4 exhibited the ability to degrade organic hydrocarbons very quickly, suggesting strain EBW4 may be a good candidate for the application to various industries.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.6
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• pp.546-551
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• 2005

[ ${\beta}-1,3-Glucan$ ] (curdlan) is a water-insoluble polysaccharide composed exclusively of ${\beta}-1,3\;linked$ glucose residues. Extracellular curdlan was mostly synthesized by Agrobacterium species and Alcaligenes faecalis under nitrogen-limiting conditions. In this study, we screened the microorganisms capable of producing extracellular curdlan from soil samples. For the first time, we reported Gram-positive bacterium Bacillus sp. SNC 107 capable of producing extracellular curdlan in appreciable amounts. The effect of different carbon sources on curdlan production was studied and found that the yield of curdlan was more when glucose was used as carbon source. It was also found that maximum production was achieved when the initial concentration of ammonium and phosphate in the medium was 0.5 and 1.9 g/L respectively. In this study the curdlan production was increased from 3 to 7g/L in shake flask cultures.

• Journal of Life Science
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• v.6 no.4
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• pp.270-277
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• 1996

Streptococcus sp J-C1 producing bacteriocin was isolated from Kimchi. The optimum conditions for bacteriocin production by Streptococcus sp. J-C1 were evaluated. For the maximum yield of bacteriocin production by Streptococcus sp. J-C1, the cell should be harvested at the late stationary phase and the temperature, pH and NaCl concentration should be 25$\circ$C, pH 8 and without the addition of NaCl, respectively. Sucrose should be used as a carbon source and organic nitrogen such as peptone should be used as a nitorgen source for the best yield. The production of bacteriocin is related to the cell growth of Streptococcus sp. J-C1. The bacteriocin from Streptococcus sp. J-C1 was active for gram positive microorganisms such as Lactobacillus sp., Leuconoctoc sp., Lactococcus sp., Streptococcus mutans, Staphylococcus aureus amd Bacillus subtilis and also active for gram negetive bacteria such as Acetobacter aceti. Antibacterial activity of the bacteriocin was completely disappeared by protease treatment.

• Journal of Microbiology and Biotechnology
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• v.8 no.3
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• pp.270-276
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• 1998

Extracellular ${\alpha}$-glucosidase was purified to homogeneity from moderately thermophilic Bacillus sp. DG0303. The thermostable ${\alpha}$-glucosidase was purified by ammonium sulfate fractionation, ion-exchange chromatography, preparative polyacrylamide gel electrophoresis (PAGE), and electroelution. The molecular weight of the enzyme was estimated to be 60 kDa by SDS-PAGE. The optimum temperature for the action of the enzyme was at $60^{\circ}C$. It had a half-life of 35 min at $60^{\circ}C$. The enzyme was stable at the pH range of 4.5~7.0 and had an optimum pH at 5.0. The enzyme preparation did not require any metal ion for activity. The thermostable ${\alpha}$-glucosidase hydrolyzed the ${\alpha}$-1,6-linkages in isomaltose, isomaltotriose, and panose, and had little or no activity with maltooligosaccharides and other polysaccharides. The $K_m$ (mM) for p-nitrophenyl-${\alpha}$-D-glucopyranoside (pNPG), panose, isomaltose, and isomaltotriose were 4.6, 4.7, 40.8, and 3.7 and the $V_{max}$(${\mu}mol{\cdot}min^-1$$mg^-1$) for those substrates were 5629, 1669, 3410, and 1827, respectively. The N-terminal amino acid sequence of the enzyme was MERVWWKKAV. Based on its substrate specificity and catalytic properties, the enzyme has been assigned to be an oligo-1,6-glucosidase.

• Korean Journal of Microbiology
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• v.45 no.2
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• pp.208-214
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• 2009

To avoid ambiguity in counting the number of colony, about 1,500 of colonies grown on B. cereus selective agar plates were grouped into 12 types by morphological difference and then identified by biochemical and 16S rDNA nucleotide sequence. Among them, seven colony types with 11 to 15 mm diameters of halo were identified as B. cereus or B. cereus subsp. cytotoxis. Five mm sized colonies with no halo, which have not been considered as B. cereus according to the manufacturer's manual, were identified as B. cereus. A colony type with double halos of only 6 mm in diameter was also B. cereus. Other three types were proven to be Enterococcus sp., Brevibacillus sp., and B. subtilis, respectively. PCR results showed that only 9 types that are identified as B. cereus strains harbor at least one of B. cereus toxin genes.

• Microbiology and Biotechnology Letters
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• v.14 no.6
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• pp.461-466
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• 1986

A highly cyclodextrin glucanotransferase producing strain of Bacillus sp. was isolated from soil, and basic studies on the characteristics of the strain and its enzyme, conditions for the enzyme production, and the enzyme utilization were carried out. The isolated strain was aerobic, motile, endospore-forming and rod-shaped bacterium. Optimum pH and temperature for the enzyme action were 6.0 and 45$^{\circ}C$, and the enzyme was stable within 5$0^{\circ}C$, and between pH 6.0 and 10.0. The highest yield of the enzyme was obtained using the medium containing 2% corn starch as a carbon source, and 5% corn steep liquor, 0.1% urea and 0.25% ammonium sulfate as nitrogen sources. The fermentation conditions for the enzyme production in a jar fermentor were cetermined to be 3$0^{\circ}C$, 200rpm, 0.6vvm and 60hr cultural period. Stevioside transglycosylation catalyzed by this enzyme was identified by high performance liquid chromatography.

• Journal of Microbiology and Biotechnology
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• v.14 no.2
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• pp.344-349
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• 2004

A gene encoding inulin-degrading enzyme of Bacillus sp. snu-7 with ORF of 1536 nucleotides was cloned. And it was overexpressed as His-tagged protein in E. coli BL21(DE3) pLysS using pRSET B vector containing mature enzyme sequence. Maximum enzyme production was achieved by IPTG (0.1 mM) induction at $OD_{600}$ 1.2 and $30^{\circ}C$ followed by 6 h incubation. The expressed protein purified through immobilized metal affinity chromatography showed molecular mass of 60 kDa on SDS-PAGE. Results of thin-layer chromatography using inulin as a substrate showed the enzyme to be an exotype inulinase capable of producing only monomeric fructose as a product. $K_m$ and $k_{cat}$, for the hydrolyses of inulin and sucrose were $2.28\pm0.08$ mM and 358.05$\pm$20.38 $min^{-l}$, and 22.02$\pm$0.41 mM and 4619.11$\pm$215.12 $$min^{-1}, respectively. Optimal activity of the exoinulinase occurred at pH 7.0 and $50^{\circ}C$.

• Journal of Microbiology and Biotechnology
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• v.6 no.2
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• pp.86-91
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• 1996

Thermostable $\beta$-mannanase from Bacillus sp. YA-14 was purified by acetone precipitation, CM-cellulose, Sephadex G-100 and hydroxyapatite column chromatography from culture supernatant. The final enzyme preparation appeared to be homogeneous on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). $\beta$-Mannanase appeared to be a monomeric protein with a molecular weight of 67, 000 daltons. The optimal pH and temperature of the enzyme reaction were pH 6.0 and $75^{\circ}C$ , respectively. The enzyme was stable at a pH range of 6.0 to 9.0 and at temperatures between 45 and $85^{\circ}C$. The kinetic constants of $\beta$-mannanase as determined with a galactomannan (locust bean) as substrate were a Vmax of 25 unit/ml and a Km of 1.1 mg/ml. The enzyme had only limited activity on galactomannan substrate. It was suggested that mg $\beta$-mannanase activity is limited by the number of branched $\alpha$-galactose residues.