• Applied Biological Chemistry
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• v.42 no.1
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• pp.1-5
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• 1999

For effective utilization of apple pomace, protopectinase(PPase) produced from Bacillus subtilis IFO 12113 was used for pectin extraction from apple pomace. Optimal conditions for enzyme treatment were found at $60^{\circ}$, pH 7.8, 48 hours with 20 : 1 ratio of substrate to enzyme. The yield of extracted pectin from water-alcohol insoluble pectin by enzyme at optimal condition was 34.3%. The purity and methoxyl content of extracted pectin by PPase at optimal condition were measured as 52.9% and 2.75%, respectively. Intrinsic viscosity and average molecular weight of extracted pectin by enzymatic method were 0.178 ml/g and $4.9{\times}10^3$, respectively.

• Korean Journal of Agricultural Science
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• v.10 no.1
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• pp.146-155
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• 1983

Fundamental study was carried out to elucidate the mechanisms of biological degradation of dyestuff in environments. A few bacterial strains which were capable of degrading amarnath were obtained from soil through an extensive screening program and identified by microbiolological properties. Conditions for bacterial growth and amaranth degradation were characterized and optimized, and the degradation products were identified. The results were as follows. 1. The most active strain A12-1 to be capable of degradation of amaranth was identified as Pseudomonas sp. 2. Optimal conditions for growth of the strain A12-1 were:$35^{\circ}C$ and pH 7.5, and growth was markedly increaesd by aeration. 3. Degradation of amaranth by the strain was accessed under similiar conditions for growth, however significantly inhibited when the culture was aerated. 4. Both bacterial growth and amaranth degradation were gradually decreased with increased concentration of amaranth in the culture. 5. Reaction of the crude enzyme from the strain A12-1 was optimal at $35^{\circ}C$ and pH 7.5 for degrading amaranth. 6. Sodium naphthionate and R-amino salt were found to be the products of amaranth degradation by the strain A12-1.

• Applied Biological Chemistry
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• v.13 no.3
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• pp.231-235
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• 1970

1. Purification of amylase system produced from Humicola sp. by a submerged culture eras carried out. 2. By DEAE-Cellulose column chromatography amylase system was separated into two fractions eluted at 0.05M and 0.5M phosphate buffer solution of pH 6.0. 3. The saccharogenic amylase was mostly composed of. the fraction of 0.05M phosphate buffer solution of pH 6.0 while the dextrinogenic amylase was perseted in fraction of 0.5M phosphate buffer solution of pH 6.0 4. It was found that the optimum pH of this saccharogenic amylase was within the range of from 4.5 to 5.5, stable pH was within the range of from 4.0 to 9.0 and optimum temperature was $60-65^{\circ}C$. This amylase was stable at $70^{\circ}C$ for ten minutes but completely inactivated $80^{\circ}C$ above.

• KSBB Journal
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• v.15 no.5
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• pp.507-513
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• 2000

The biosynthesis of lovastatin, a cholesterol lowering agent formed by the filamentous fungus Aspergillus terreus, was examined in a 2.5 L jar fermenter. In batch bioreactor cultures conducted at various agitation rates, 400 rpm showed the best result in terms of lovastatin production. Notably, the effect of pH on lovastatin biosynthesis was found to be significant: when the pH was controlled at around 5.8 during the whole fermentation period, lovastatin concentration reached 598 mg/L, which is much hihger than the amounts obtained by pH-uncontrolled and pH 7.4-controlled fermentations. In addition, both L-histidine and L-tryptophan were observed to be favorable amino acids for the enhancement of lovastatin production when 6 g/L of the respective amino acids were supplemented at the beginning of the fermentation period. By further optimization of the production media and the physical environment, lovastatin production was increased to 836 mg/L (3.5 mg/L/hr) which is approximately 10 times higher than the productivity of the basic control culture.

• Applied Biological Chemistry
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• v.35 no.5
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• pp.410-414
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• 1992

Endoinulase from Streptomyces sp. S56 was immobilized by adsorption on DEAE-cellulose in 0.01 M citrate-sodium phosphate buffer, pH 6.0 and the properties of immobilized and free enzymes were investigated. The immobilized enzyme preparation, having 40 inulase activity units per dried matrix, revealed the maximal activity at $pH\;4.5{\sim}5.5$ and $55{\sim}60^{\circ}C$ and were most stable at pH 6 and 45^{\circ}C$. The immobilization caused a drop in optimum pH and affinity toward inulin, a slight increase in optimum temperature, an important increase in thermal stability and maximum reaction velocity. The immobilized endoinulase hydrolyzed the tuber extract of jerusalem artichoke and inulin, mainly into fructose and inulobise, degrading 63 and 78% of the total sugar respectively, within 48 hrs in batch reactor.

• Korean Journal of Food Science and Technology
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• v.43 no.3
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• pp.303-314
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• 2011

The purpose of this study was to determine the optimal mixing conditions for two different amounts of added mulberry powder and fresh cream to prepare functional chocolate with added mulberry powder. The experiment was designed according to the central composite response surface design, which showed 10 experimental points, and included two replicates for mulberry powder and fresh cream. The physiochemical, mechanical, and sensory properties of the test were measured, and these values were applied to the mathematical models. The results of the physiochemical and mechanical analyses of each sample, including pH, moisture content, total phenolic content, DPPH free radical scavenging activity, color L, color b, hardness, gumminess, and cohesiveness showed significant differences. The sensory characteristics of the samples tested were significantly different in flavor, texture, sourness, bitterness, and overall acceptability. The optimum formulation calculated by numerical and graphical methods was 25.76 g mulberry powder and 72.21 g fresh cream.

• KSBB Journal
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• v.11 no.3
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• pp.303-310
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• 1996

The marine microalga Isochrysis galbana Parke was studied to optimize its growth conditions in flask culture. Important medium components studied include nitrogen source, buffer, trace elements and vitamins. Environmental conditions include pH, temperature, light intensity, mixing extent and working volume. The medium prepared from natural sea-waters gave a higher final cell density than the medium prepared from synthetic sea-water Nitrate was a better source than ammonium. In the range of 0.4∼2mM, the final cell density was proportional to the initial nitrate concentration and the cell yield was estimated to be 8.5g dry cell wt/g N. For phosphate, optimal growth was observed in 0.1∼1.0mM but a considerable variation in pH was resulted. The addition of Tris at 5mM or 7mM could stabilize the medium pH, but this significantly reduced both growth rate and final cell density, The effect of trace elements and vitamins was negligible. Optimal temperature and initial pH were $20^{\circ}C$ and 8. When the intensity of incident light was varied in the range of 400∼2100 lux, the growth rate increased from 10mL to 70mL, the final cell density decreased although the initial growth rate did not change. Optimal agitation speed was 100rpm when working volume was 30mL. With optimal conditions, the maximum specific growth rate obtained was 0.021hr-1 and the final cell density was 1.1g/L.

• Korean Journal of Microbiology
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• v.30 no.4
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• pp.305-309
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• 1992

Cytosine deaminase (EC 3.5.4.1) from BaciNus stc~urorhermophilus was partially purified 7.2-fold with an overall yield of 52.7%. The partially purified enzyme deiiminated cytosine only.but not 5-methylcytosine and 5-fluorocytosine. The apparent Michaclis constant. Km valuefor cytosine was 5.9 mM. The enzyme was relatively stable in the range of pH 4.0 to 7.0.furthermore extremely thermo-stable : more than 75'X) of the activity was remained afterheating at 80$^{\circ}$C for I0 min at pH 6.5. The enzyme had a pH optimum at around pH7.0 to 7.5. and temperature optimum at 35 to 31$^{\circ}$C. And the activation energ (En value)determined from an Arrhenius plot was 26 Kcal/mol. The enzyme activity was stronglyinhibited by heavy metal ions such as Cd", Hg". Cut' at 1 mM, anJ by o-phenanthroline,and p-chloromcrcuribcnzoate at I mM. But the enrymc activity was activatetl increased byGMP, and CMP at 1 mM.ased by GMP, and CMP at 1 mM.

• Journal of the Korean Wood Science and Technology
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• v.32 no.4
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• pp.58-65
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• 2004

This study was performed to investigate the protease activity from fruit body of Sarcodon aspratus and its features. The specific protease activity was increased with the increasing purification steps, 2.62 times by desalting, 17 times by CMC column chromatography, 113.8 times by DEAE-Sephadex A-50 column chromatography, and 728.3 times by Sephadex G-75 column chromatography. Proteases were identified as two different enzymes having different isoelectric points at pH 4.35 (its recovery rate 8%) and pH 4.7 (its recovery rate 3.5%). Those proteases were purified by 3,025 folds and 3,257 folds in terms of specific activity. Two proteases having different isoelectric points had similar enzymatic properties. This protease was estimated to be 43,000 daltons of molecular weights by SDS-PAGE. This protease with optimum pH 4 was almost stable in the pH range of 4~7. Optimal temperature of protease activity was 40 to 50℃, and the protease activity was completely inhibited at 70℃ for 30 min.

• Clean Technology
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• v.8 no.4
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• pp.199-203
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• 2002

To investigate the optimal conditions for biodegradation of toluene by Pseudomonas fluorescens KCTC 1767 in a batch soil-bioreactor, the effects of rpm change from 60 to 180, and temperature change from $15^{\circ}C$ to $30^{\circ}C$ in a batch culture and the flow rate change from 55 mL/min to 85 mL/Min in soil-bioreactor on the biodegradation of toluene were studied. In a batch culture the optimal operating conditons were 60 rpm, and $30^{\circ}C$ at initial pH 7, In a soil-bioreactor the optimal flow rate was 55 mL/min in the flow rate of circulation. The lower flow rate of circulation may help to biodegrade toluene adsorped in soil and dissolved in underground water.