• Microbiology and Biotechnology Letters
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• v.30 no.1
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• pp.1-7
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• 2002

Phytase from Escherichia coli WC7 was purified from cell extracts and its molecular mass was estimated to be 45 kDa by SDS-PAGE. Its optimum temperature and pH for phytate hydrolysis was 6$0^{\circ}C$ and pH 5.0, respectively. The enzyme was stable up to 6$0^{\circ}C$ and over broad pH range (pH 2-12). The enzyme had higher affinity for sodium phytate than p-nitrophenylphosphate (pNPP). That is, the apparent Km value for sodium phytate and pNPP were $0.15\pm$0.02 mM and 2.82$\pm$0.05 mM, respectively. The gene encoding the phytase was cloned in E. coli XL1-Blue. Sequence analysis showed an open reading frame of 1241 Up encoding a signal peptide (22 aa) and a mature enzyme (410 aa). WC7 phytase was expressed up to 17.5 U/ml in the transformed E. coli XL1-Blue/pUEP, which was 23-fold higher than the activity from wild strain.

• Microbiology and Biotechnology Letters
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• v.30 no.4
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• pp.346-351
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• 2002

A bacterium producing the neutral pretense was isolated from soil, and was identified as Bacillus sp. DS-1 by 16S rRNA sequence comparison and biochemical determinations. The production of protease from Bacillus sp. DS-1 was increased 20% and 30% by the additions of 1% glucose and 1% yeast extract, respectively. The optimum pH and temperature for the protease activity were pH 7.0 and 55$^{\circ}C$. Bacillus sp. DS-1 produced a metalloprotease as a major protease in culture medium, since the pretense activity in culture supernatant was inhibited by the presence of 1 mM EDTA significantly.

• Korean Journal of Environmental Agriculture
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• v.9 no.2
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• pp.97-103
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• 1990

In order to determine the major biochemical degradation factors of the two organophosphorus insecticides, diazinon and dursban, the activities of monooxygenase(m. o.) and ${\alpha}$, ${\beta}-esterase$ were studied in submerged soil under laboratory conditions at $30{\pm}1^{\circ}C$ The degradation rate of diazinon by microorganism showed 1.5 times higher than dursban. The m. o. activity increased from 12hrs and 3days after application of diazinon and dursban, respectively. But the ${\beta}-esterase$ activity showed maximum at one day after application of dursban and $5{\sim}8$ days after diazinon application. Also, the ${\beta}-esterase$ activity was about 10 times higher than ${\alpha}-esterase$. Hence, it was concluded that the biological degradation of diazinon was mainly attributed to m. o. activity and the degradation of dursban to ${\beta}-esterase$ activity.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.5
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• pp.792-797
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• 2012

Glomalin-related soil protein has been suggested as an enhancer for soil stability by promoting the aggregation. In this study, we examined the concentrations of glomalin and characteristics of microbial community in 20 paddy soils sampled from Gyeongnam Province. Total soil glomalin as glomalin-related soil protein (GRSP) had a significant positive correlation with soil organic matter (p<0.01) and soil dehydrogenase activity (p<0.01). The concentration of GRSP significantly correlated to soil microbial biomass carbon (p<0.001) and the total bacterial community (p<0.01) in paddy soils. In addition, the GRSP had a significant positive correlation with gram-negative bacteria community (p<0.05) and ratio of cy19:0 to 18:$1{\omega}7c$ (p<0.05) in paddy soils. In conclusion, the concentration of GRSP could be an indicator of soil health that simplify the inspection steps for sustainable agriculture in paddy soils.

• Applied Biological Chemistry
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• v.41 no.1
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• pp.6-12
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• 1998

To extract insoluble proteins and to improve functional properties of abolished proteins, a protease producing Aspergillus sp. MS-18 was isolated from soil. The enzyme was purified and its enzymological characteristics were investigated. It was found that production of protease reached to the maximum when the wheat brae medium containing, 3% arabinose, 0.5% polypepton, 0.1% $(NH_4)_2SO_4$ and 0.2% magnesium chloride was cultured for 3 days. Protease was purified 16.9 folds after ion exchange chromatography and gel filtration and the specific activity was 340.4 unit/mg. Purified enzyme was confirmed as a single band by the polyacrylamide gel electrophoresis. The molecular weight of protease was estimated to be 30,000. Crystalization form of purified protease was a stick shape with rounding edges. The optimum pH and temperature for the protease activity were 9.0 and $60^{\circ}C$, respectively. The enzyme was stable in pH 7.0-12.0 at $50^{\circ}C$. The activity of purified enzyme was inhibited by $Hg^{2+}$, $Cu^{2+}$, $Zn^{2+}$ and $Pb^{2+}$, whereas it was activited by $Na^+$, $Mg^{2+}$ and $Mn^{2+}$. The activity of the protease was inhibited by the treatment with ethylenediaminetetraacetic acid and phenylmethane sulfonyl fluoride. The result suggests that the purified enzyme is a serine protease with metal ion at active site. Km and Vmax of purified protease were $29.33\;{\mu}mole/L$ and $5.13\;{\mu}g/min$, respectively.

• Microbiology and Biotechnology Letters
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• v.9 no.4
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• pp.207-212
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• 1981

A strain of Penicillium sp. which produces considerable amount of $\beta$-galactosidase was selected from extracellular $\beta$-galactosidase-producing fungi isolated from soil. The enzyme was found to be very stable in neutral pH range. Maximum enzymatic activity was reached after 72 hr of incubation in a wheat bran medium at 3$0^{\circ}C$. Productivity of the enzyme appeared not to be affected by the addition of carbon sources to the medium but the activity of the enzyme was increased from 14% to 85% by the addition of various nitrogen sources. The enzyme extracted from the wheat-bran culture of the Penicillium sp. was purified to 5050-fold by ammonium sulfate fractionation, SP-Sephadex C-50 chromatography, Ultrogel AcA 44 filtration and hydroxyapatite chromatography. The purified $\beta$-galactosidase was homogeneous on ultracentrifugation and disc electrophoresis.

• 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.

• KSBB Journal
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• v.14 no.1
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• pp.103-108
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• 1999

A bacterium having strong fibrinolytic activity, S7-16 strain, was isolated from soil. The isolated bacterium was identified and named as Bacillus sp. S7-16. The optimal composition of the medium for the production of fibrinolytic enzyme by Bacillus sp. S7-16 was 0.5%(w/v) polypeptone, 0.5%(w/v) yeast extract, 0.3%(w/v) NaCl, 0.1% (w/v) $KH_2PO_4,\;0.3%(w/v)\;K_2PHO_4,\;and\;0.01%(w/v)\;MgSO_4{\cdot}7H_2O$. The optimal temperature and initial pH of the medium for the production of the enzyme were $35^{\circ}C$ and 7.0, respectively. The maximum production of the fibrinolytic enzyme was obtained after 24 hours of the incubation. Under the above conditions, the culture supernatant had strong fibrinolytic activity. Within pH4~11, the crude fibrinolytic enzyme was stable. The enzyme was stable up to $50^{\circ}C$. The optimum pH and temperature for the enzyme activity were around 7.5 and $40^{\circ}C$, respectively.

• Microbiology and Biotechnology Letters
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• v.30 no.3
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• pp.287-292
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• 2002

Lignin-peroxidase (LiP) has been considered as one of the most important industrial enzymes for biodegradation of various recalcitrant toxic compounds such as chlorinated aromatic hydrocarbons and azo-dyes. Recently, several soil actinomycetes have been reported to secrete a functionally-similar lignin-peroxidase called actinomycetes lig-nin-peroxidase (ALiP). In this manuscript, we isolated over 100 morphologically distinct actinomycetes from the contaminated soils around 10 different gas stations located nearby the Kyung-An river. Among these actinomycetes screened based on the congo-red dye-decolorization activities, one newly-isolated actinomycetes named SMA-2 showed the most significant dye-decoloring activity on the congo-red plate as well as a significant ALiP activity in a yeast-extract-malt-extract liquid media supplemented with starch. The optimum SMA-2 culture condition fur ALiP production was determined and the kinetic parameters fur the SMA-2 AkIP activity were characterized. The optimally-cultured SMA-2 also exhibited the oxidation activities toward various recalcitrant aromatic compounds including phenol, 2- chlorophenol, 4- chlorophenol, 2,4- dichlorophenol ,2,6- dichlorophenol, and 2,4, f-trichlorophe - not, suggesting a potential application of SMA-2 for contaminated soil bioremediation.

• Microbiology and Biotechnology Letters
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• v.8 no.2
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• pp.125-133
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• 1980

A microorganism which produced D-glucose isomerase was identified to be similar to Streptomyces antibioticus on the morphological, cultural and physiological characteristics except the spore chain and the utilization of sucrose. D-xylose grown cells of Streptomyces sp. strain K-17 were disrupted by grinding with sea sand. D-glucose isomerase was partially purified with the fractionation by ammonium sulfate, Mn-treatment, DEAE-cellulose column chromatography, DEAE-sephadex (A-50) column chromatography and gel filtration of sephadex G-200. The enzyme was purified about 380 fold with 25 ％ recovery.