• KSBB Journal
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• 제10권2호
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• pp.176-182
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• 1995

The environmental and physiological factors affecting the production of exopolysaccharide (Methylan) and Poly-${\beta}$-hydroxybutyrate(PHB) by Methylobacterium organophilum were investigated. The maximum PHB content was obtained at $38^{\circ}C$ whereas maximum polysaccharide concentration was $3.54g/\ell$ at $30^{\circ}C$. Optimum pH was pH 7-8 for PHB production and pH 6-7 for polysaccharide production, respectively. Under the condition of $Mo^{2+}, Mg^{2+} or Mn^{2+}$ limitation with nitrogenlimitation, the PHB accumulation was increased, whereas the polysaccharide production was decreased as compared with that of solenitrogenlimitation. Under the condition of sole K+ limitation, cell growth was significantly inhibited and no polysaccharide was produced. However, the PHB content was as high as 60% of dry cell weight. Effect of C/N ratios (methanol/ammonium) in the feeding solution was examined for the simultaneous production of polysaccharide and PHB. The higher ratio of C/N showed the lower cell growth, higher content of PHB in cells, and higher yield of polysaccharide.

• Korean Journal of Microbiology
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• 제36권1호
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• pp.33-39
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• 2000

Some of thermophilic fungi which has growth-promoting effect on Pleurotus ostreatus were isolated from compost during high temperature fermentation process. The temperature optima of 7 isolated thermophilic fungi were $50^{\circ}C$ on PDA media. Isolated strains S-1 and S-2 have the best mycelial growing rate, so these isolates were expected as excellent thermophilic fungi for high temperature composting and mycelial growing of oyster mushroom. In liquid culture, the optimal pH of thermophilic fungi observed variously, pH 7.0-10.0 but most of thermophilic fungi grow well in pH 8.0-pH 9.0 and the final pH of media after cultured was done pH 5.5-6.0. In liquid culture of thermophilic fungi on the optimal condition, S-2 have the best mycelial growing rate. The growing rate of thermophilic fungi S-1, S-2, S-5, and S-10 on lignocellulosic substrates was good but Humicola grisea var. thermoidea, well know thermophilic fungi which has growth-promoting effect on Agaricus bisporus, was poor and which was well grown on PDA at $50^{\circ}C$, pH 7.0. Isolated strain S-1 was identified as Trichophyton sp. and other 6 strains were identified as Sepedonium sp. by morphological characteristics.

• Applied Biological Chemistry
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• 제15권3호
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• pp.207-211
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• 1972

In order to investigate the action of thermophilic fungi on the xylan and its related substances, xylanase and laminaranase were examined using Myriococcum albomyces. In the extract from bran culture of Myriococcum albomyces, xylanase and laminaranase activity were recognized. 1) The optimum pH for xylanase and laminaranase activity were found to be pH 5.0 and pH 6.0. 2) The optimum temperature for xylanase and laminaranase activity were found to be $55^{\cicr}C$. 3) Thermal stability of xylanase for 55 minutes at $65^{\cicr}C$ and laminaranase for 60 minutes at $65^{\cicr}C$ did not influence their stability.

• Microbiology and Biotechnology Letters
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• 제4권4호
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• pp.145-151
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• 1976

Cultural characteristics of a strain of Streptomyces sp. K-14 (KFCC 35051) producing glucose isomerase were demonstrated. The glucose isomerase was produced when the strain was grown in the medium containing pure xylan or xylan.containing materials such as wheat bran or com cob. The optimum condition was attained in a culture medium composed of 3 % wheat bran or com cob, 2 % com steep liquor, 0.1% $MgSO_4$$7H_2O$ and 0.012 % $CoSO_4$$7H_2O$ for the production of the glucose isomera,e. The production of the enzyme reached to a maximum level when the strain was cultured for 40 hrs $30^{\circ}C$ and pH 7.0.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 한국표면공학회 2009년도 춘계학술대회 논문집
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• pp.141-141
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• 2009

흑색 3가크롬용액을 최적의 전착조건을 찾기 위해서 pH와 온도의 변화에 따란 Hull-cell test, 두께측정, 분극실험을 실시하였다. 온도가 올라갈수록, pH가 낮을수록 도금층의 두께가 두꺼워졌으나, 온도 $40^{\circ}C$, pH 3.4-3.8일때 균일한 도금층을 얻을 수 있었다.

• Analytical Science and Technology
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• 제16권6호
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• pp.504-508
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• 2003

A carbon paste electrode was constructed with peroxidase extracted from Horseradish and the variation of the response of the sensor with pH was investigated. Current profiles showed two highest sensitivities at two pH values respectively. In addition, two bands were observed in the electrophoretic expansion. A coincidence of the two experimental results added support to the possibility that the biosensor has two different isozymes. Assuming that current profiles are the sum of two gaussians, we deconvoluted them and determined the optimum pH of peroxidase isozymes.

• Journal of the Korea Organic Resources Recycling Association
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• 제13권4호
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• pp.107-117
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• 2005

The objective of this study was to investigate the proper operation conditions of fenton oxidation such as initial pH, $H_2O_2/Fe^{2+}$ ratio, $H_2O_2/Fe^{2+}$ dosage amount, and neutralizing agent for pretreatment of the livestock wastewater. Fenton oxidation reagents were reacted with the livestock wastewater for 2 hours at 120 rpm and the settling was performed for 2 hours using jar-tester apparatus under the different experimental conditions. And then the supernatant was sampled and measured for the residual $H_2O_2$, $COD_{Cr}$, and SS. The results are as follows; optimum initial pH=4, optimum $H_2O_2/Fe^{2+}$ ratio=10:1, optimum $H_2O_2/Fe^{2+}$ dosage amount=5,000/500 mg/L and $Ca(OH)_2$ as proper neutralizing agent. The removal efficiency of $COD_{Cr}$ and SS were 43% and 84% under those optimal fenton oxidation conditions.

• KSBB Journal
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• 제15권3호
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• pp.268-273
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• 2000

A microbiological hydrogen production process was optimized. Anaerobic photosynthetic bacteria like Rhodospirillum rubrum which is known to produce hydrogen from carbon monoxide efficiently and remove sulfur was used. To evaluate the potenital of this microorganism the optimization of media fermentation condition light intensity and light requirement for CO conversionwas tried in batch cultures and the continuous fermenter was also applied for this process. The gas residence time on CO conversion was sought out to get high conversion of carbon monoxide to hydrogen. Through this study the possibility of microbial synthtics gas concersion process was proposed.

• The Korean Journal of Mycology
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• 제48권3호
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• pp.273-284
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• 2020

Calocybe indica is an edible mushroom commercially cultivated in India and other tropical countries. In this study, the culture characteristics and optimal conditions of milky mushroom strains were determined. The growth temperature and pH range of milky mushrooms was extensively investigated between 15-35 ℃ and pH 3-11. For efficient cultivation, 20 types of nutrient sources were selected that consisted of one of 21 types of carbon sources, 6 organic nitrogen sources, 6 inorganic nitrogen sources, 13 amino acids, 6 organic acids and 12 inorganic salts. The impact of each of the selected nutrition sources and their concentration on growth was investigated. The optimum pH and temperature were determined to be pH 6.0 and 15 ℃, respectively. The optimum concentration of medium elements for the mycelial growth of C. indica was determined to be as follows: carbon source, 2% maltose; organic nitrogen source, 1% yeast extract; inorganic nitrogen source, 0.1% NaNO₃; amino acid, 0.7% asparagine; organic acid, 0.07% acetic acid; inorganic salt, 0.07 mM MnSO₄.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.571-574
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• 2000

Hydrolase is a group of the most widely used enzymes in industrial biological processes. Generally, their activities are easily changed with pH. With this characteristics, research for the optimal pH of hydrolases is required to obtain the optimization of process conditions. We selected xylanase, lysozyme, glucoamylase and barnase as model enzymes. To predict optimum pH of hydrolases, the calculation program based on Tanford-Kirkwood(TK) model was used. Results show that charge difference of catalytic residues is an important parameter deciding optimum pH and when charge difference of catalytic residues is maximum, optimum pH of the hydrolase establishes.