• Applied Biological Chemistry
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• v.22 no.4
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• pp.191-197
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• 1979

${\beta}-Tyrosinase$ was purified and crystallized from cells of Escherichia intermedia A-21 grown in a medium supplemented with 0.2% L-tyrosine. Molecular weight of its subunit, Km value and absorption spectra were determined. Crystallization methods were also studied to eliminate any unnecessary procedures. The results obtained were as follows: 1. The purification procedure included ammonium sulfate fractionation, dialysis against potassium phosphate buffer, pH 6.0 and pH 7.0, and DEAE-Sephadex column chromatography. In the column chromatography, 11 mg of protein was applied per ml of DEAE-Sephadex for efficiency. 2. Steps of protamine sulfate treatment and Sephadex G-150 gel filtration could be eliminated for this enzyme from the known procedures. 3. The purified enzyme was dissolved in 0.01M potassium phosphate buffer containing 2-mercaptoethanol, with a concentration of 20mg/ml. Crystalline enzyme, which appears as hexagonal rods, was obtained by adding solid fine powdered ammonium sulfate to the enzyme solution. 4. Absorption maxima of the enzyme appeared at 340 and 430nm when associated with pyridoxal phosphate. 5. Km value of the enzyme for L-tyrosine was $2.31{\times}10^{-4}M$ and the molecular weight of its subunit was determined by SDS-polyacrylamide electrophoresis to be approximately 50,000.

• Journal of the Korean Society of Food Culture
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• v.5 no.2
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• pp.269-274
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• 1990

This study was conducted to determine invertase activity in persimmon during the drying process and characterize the purified enzyme. As drying proceeded, invertase activity increased until 10 days and decreased gradually afterwards. Invertase in persimmon fruit was extracted with 250 mM potassium phosphate sulfate buffer at pH 7.4. The enzyme was purified by means of ammonium sulfate fractionation, column chromatography on DEAE-cellulose and gel filtration on Sephadex G-200 column. The optimal temperature of enzyme was $40^{\circ}C$ and optimal pH was 5.0 and 6.0 for sucrose and raffinose, respectively. The enzyme was stable up to $50^{\circ}C$ and pH 3-6. The Km value of the enzyme, with sucrose as a substrate, was 2.5mM. Electrophoretic pattern of purified enzyme solution showed a single band.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.5
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• pp.399-407
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• 2013

Organic grape was generally produced in rainshield or plastic greenhouse culture while most of fruits were produced in open field. But little attention has been given to soil properties with different culture facilities in organic grape cultivation. This study was conducted to investigate soil physico-chemical properties of organic grapes farms with different culture facilities and soil management practices. Organic fertilizer was main resource to manage soil at organic grapes farms. Organic grapes farms were applied with total amount of organic fertilizer at one time, either at basal or additional fertilization, whereas conventional grapes farms applied with split fertilization. Bulk density and penetration resistance of soil were lower at both rainshield and green manure-applied plastic greenhouse cultures than those at clean plastic greenhouse culture. Especially, in plastic greenhouse, sod culture with natural weed after green manure application was more effective than general sod culture in improving physical properties of the rhizosphere. The contents of organic matter, available phosphate and exchangeable potassium tended to increase in the soils applied with green manure, and the difference of soil chemical properties were significant between rainshield and plastic greenhouse cultures. The optimum soil management was required in plastic greenhouse because pH, available phosphate and exchangeable cations reached over optimum range. Consequently, the ground cover management is the key factor to affect the chemical properties as well as soil physical properties extensively in plastic greenhouse. It is found that sod culture with natural weed after green manure application resulted in enhancement of utilization efficiency of nitrogen, phosphoric acid and potassium in soil in comparison with general sod culture.

• Korean Journal of Soil Science and Fertilizer
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• v.16 no.2
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• pp.162-167
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• 1983

These studies were carried out to investigate the effects of organic matter on the leaching of chemical constituents in paddy soil. Rice plants were cultured in paddy soil to which rice straw and compost were applied and then chemical properties of percolated water were analysed. The results were as follows: In the paddy soil cultured with rice plants, the pH value of soil was higher in the compost plot than in the rice straw plot. The leaching of iron, managanese, calcium, magnesium and phosphate was increased by cultivation of rice plant, but that of potassium, ammonium, and silica was decreased. When rice straw was applied in the paddy soil, the leaching of iron, managanese, phosphate and silica was increased during the growing periods, while that of calcium, magnesium, potassium and ammonium was increased by application of compost.

• Microbiology and Biotechnology Letters
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• v.14 no.6
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• pp.441-446
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• 1986

Some properties of extracellular guanine deaminase produced by Pseudomonas synxantha A3 were studied. The enzyme was stable at pH 6.5-7.5 and generally stable when it was incubated at 4$0^{\circ}C$ for 10 minutes but inactivated gradually above 4$0^{\circ}C$. When the enzyme in 0.2M potassium phosphate (pH 8.0) was stored at room temperature, it was stable for thirty days. Alcohols and acetone were not effective for the eyzyme stability. The optimum pH and temperature for the enzyme activity were around pH 7.0-8.0 and 5$0^{\circ}C$, respectively. The enzyme was inhibited by 1mM of Hg$^{++}$, Ag$^+$ and Li$^+$ and by 0.1mM of Ag$^+$ with about 50% loss of activity. The enzyme inhibited by Li$^+$ was reactivated by EDTA. 1 mM of pentachlorophenol and p-CMB inactivated the enzyme with 50% and 40% loss of activity, respectively. The enzyme inactivated by p-CMB was reactivated by glutathione.

• Microbiology and Biotechnology Letters
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• v.45 no.4
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• pp.330-342
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• 2017

Statistical design of experiments was employed to optimize the media composition for the production of laccase from Bacillus sp. PK4. In order to find the key ingredients for the best yield of enzyme production from the selected eleven variables viz yeast extract, glucose, zinc sulphate, copper sulphate, potassium chloride, magnesium sulphate, calcium chloride, ferrous sulphate, sodium chloride, potassium dihydrogen phosphate ($KH_2PO_4$) and dipotassium hydrogen phosphate ($K_2HPO_4$), Plackett-Burman design was applied. The $MgSO_4$, $FeSO_4$, and $CuSO_4$ showed positive estimate, and their concentration optimized further. The steepest ascent method and Box-Behnken method revealed that 1.5 mM $MgSO_4$, 0.33 g/l $FeSO_4$ and 1.41 mM $CuSO_4$ were optimal for the laccase production by Bacillus sp. PK4. This optimization strategy leads to enhancement of laccase production from 2.13 U/ml to 40.79 U/ml. Agro-wastes residues replace the carbon source glucose in the optimized media namely sugarcane bagasse, wheat bran, rice husk, and groundnut shell, among these groundnut shells (117 U/ml) was found to enhance the laccase production significantly. The laccase produced by Bacillus sp. PK4 was found to have the potential to degrade persistent organic pollutant benzo[a]pyrene.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.spc
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• pp.33-39
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• 2009

The practice of supplying nutrients for paddy soil with sustaining human health and ecological soundness is to utilize indicators considering soil chemical reactions. The long-term basis experiment of fertilizer and amendment of paddy soil and an experiment of yield response of soil types on nitrogen level from 2000 till 2002were used to search indicators of nutrient supplying capacity related to soil chemical reactions. Chemical reactions of paddy soil was composed of dissociating and/or adsorbing nutrients and of decomposing soil organic matter (SOM) into $H^+$, $e^-$, $CO_2$ in paddy soil. The indicators of nutrient supplying capacity, which were established by considering soil chemical reactions, were SOM or soil protein for nitrogen and available phosphate for phosphorus and cation exchangeable capacity (CEC) and exchangeable potassium for potassium. Korea has used fertilizer recommendation equations established with the indicators of nutrient supplying capacity for paddy soil.

• Korean Journal of Environmental Agriculture
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• v.33 no.1
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• pp.24-29
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• 2014

BACKGROUND: Recently, as the consumption of fresh jujube is increased, fertilizer in jujube cultivation is excessively used to supply nutrient for large fruit produce. This study was conducted to obtain the useful data related to optimum nutrient management technique for fresh jujube cultivation. METHODS AND RESULTS: Nutrient contents of the jujube orchard soils were investigated at 30 different jujube orchards in Boeun, Chungbuk. Soil samples were collected from the different orchards in June, both 2012 and 2013. Soil chemical properties such as pH, organic matter, available phosphate, and exchangeable potassium, calcium, and magnesium were analyzed. Soil available phosphates in optimum level for jujube cultivation were 7% and 13% of total samples in the 2011 and 2012 respectively, and 73% and 57% were higher than optimum level. In Exchangeable K, 37%, 30% were optimum level, 63%, 67% were higher in the year 2011 and 2012 respectively. CONCLUSION: These results showed that nutrient contents of soils were accumulated in jujube orchard of Boeun area. Especially, available phosphate and exchangeable potassium were greatly higher than their optimum level for jujube cultivation respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.16 no.3
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• pp.225-230
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• 1983

The proteolytic bacteria were isolated from the market foods such as ground beef, cooked shrimp meat, perch fillet, oyster meat, beef with textured vegetable protein and fish digest distributed at supermarket in Corvallis, Oregon, U.S.A. Two hundred and twenty-eight strains($30.8\%$) have proteolytic activity from 740 strains isolated from the examined samples and the strongest proteolytic strain among them was identified as a Streptococcus sp. Its maximum growth was showed at about 6 hours culture at $37^{\circ}C$ with shaking incubator in the medium added $0.15\%$ potassium phosphate monobasic and $0.4\%$ potassium phosphate dibasic, while the strongest activity of its extracellular protease was observed after 7 hours culture. The exoenzyme produced by the Streptococcus sp. was observed as a metal chelator sensitive protease, which are strongly inhibited by EDTA and o-phenanthroline but not affected by phenylmethylsulfonylfluoride and p-hydroxymercuribenzoate.

• Applied Biological Chemistry
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• v.39 no.6
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• pp.449-454
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• 1996

We investigated the optimal condition for the production of extracellular pretense(a cuticle-degrading pretense) from entomopathogenic fungus Beauveria bassiana(ATCC7159) in liquid medium by adding of gelatin, bovine serum albumin(BSA), casein and polypeptone. The optimal induction medium for production of extracellular pretenses is composed of 0.5% polypeptone, trace elements and 50 mM potassium phosphate(pH 6.0). In this condition, the production of extracellular pretenses increased rapidly after the 24hrs, peaking at the third day and there was little inductive effect in culture broth more than pH 7.0. The pretenses were inhibited by phenyl methyl sulfonyl fluoride(PMSF). High activity of pretense was showed both range of pH 8.5 and 11.5 and also detected by three different portions of slice gel derived from non-denaturing isoelectricfocusing gel. At least three different extracellular pretenses are produced in optimal production medium when polypeptone is used as the sole carbon and nitrogen source.