• Microbiology and Biotechnology Letters
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• v.23 no.5
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• pp.602-608
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• 1995

The aim of the present research program was to construct an optimum fermentation system and to characterize the properties of cathepsin B inhibitor from Streptomyces chromofuscus SMF28. Glucose and casitone were proved to be good carbon source and nitrogen source, respectively. The production of inhibitor was high at lower concentration than 10 mM of inorganic phosphate. The optimum temperature and pH for the production of inhibitor were 30$\circ$C and pH 7, respectively. The production of inhibitor was related to mycelial growth and was affected by medium composition. The inhibitor in culture filtrate of S. chromofuscus SMF28 was purified by butanol extraction, silica gel chromatography, Amberlite IRC-50 (H$^{+}$ form) chromatography, preparative TLC, and preparative HPLC. From amino acid analysis and UV, IR, $^{1}$H-NMR spectroscopic analysis, the inhibitor was identified as a peptide containing valine and phenylalanine derivative.

• Journal of Microbiology and Biotechnology
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• v.1 no.4
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• pp.288-292
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• 1991

The aim of the current study is to evaluate the effects of medium compositions on the production of protease inhibitor in Streptomyces sp. SMF13. The production of protease inhibitor was counter-currently linked to extra-cellular protease, which were regulated by the culture conditions. Nitrogen source was the most critical ingredient affecting the production of protease inhibitor and protease. Carbon source was an important factor to determine the culture pH which affected very clearly the formation of protease and protease inhibitor. Inorganic phosphate inhibited the protease inhibitor production which was linked to the cell growth rate, although the optimal conditions for the production of protease inhibitor were not favouring to the cell growth.

• Microbiology and Biotechnology Letters
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• v.24 no.2
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• pp.185-190
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• 1996

Some microorganisms including yeasts produce surface tension-decreasing biosurfactants. The strain G-1, the best producer of biosurfatants was isolated from the soil and identified as Rhodotorula sp., which was not discribed any report. The Rhodotorula sp. G-1 produced biosurfactant from vegetable oils, but failed to produce it from n-alkane or carbohydrate. Yeast extract was found to be more effective for the biosurfactant production as nitrogen source than any other inorganic nitrogen source. The composion of the optimal medium contained the following conponents: soybean oil 4%, glucose 2%, yeast extract 0.5%, KH$^{2}$PO$^{4}$ 0.1%, K$^{2}$HP0$^{4}$ 0.l%, MgSO$^{4}$ 5%, CaCl$^{2}$ 0.01%, NaCl 0.01%, pH 6.0. The surface tension activity was increased to 14% when, at first, the culture broth was fermented with only soybean oil as carbon sourse, and after 90 hours, feeded glucose, than that Of glucose and soybean oil added to it simultaneously. The maxium yield of the biosurfactant was about 15 g/l by after 90 hours, the feeding method of glucose.

• Environmental Engineering Research
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• v.24 no.2
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• pp.271-278
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• 2019

Mass cultivation of microalgae is necessary to achieve economically feasible production of microalgal biodiesel. However, the high cost of nutrients is a major limitation. In this study, corncob extract (CCE) was used as an inorganic and organic nutrient source for the mass cultivation of Chlorella vulgaris (C. vulgaris). Chemical composition analysis of CCE revealed that it contained sufficient nutrients for mixotrophic cultivation of C. vulgaris. The highest specific grow rate of C. vulgaris was obtained at pH of 7-8, temperature of $25-30^{\circ}C$, and CCE amount of 5 g/L. In the analysis using various growth models, Luong model was found to be the most suitable empirical formula for mass cultivation of C. vulgaris using CCE. Analysis of biomass and production of triacyglycerol showed that microalgae grown in CCE medium produced more than 17.23% and 3% more unsaturated fatty acids than cells cultured in Jaworski's Medium. These results suggest that growing microalgae in CCE-supplemented medium can increase lipid production. Therefore, CCE, agricultural byproduct, has potential use for mass cultivation of microalgae.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.4
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• pp.439-454
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• 2008

The purpose of this study was to extensively identify $PM_{10}$ sources and to estimate their contributions to the study area, based on the analysis of the $PM_{10}$ mass concentration and the associated inorganic elements, ions, and total carbon. The contribution of $PM_{10}$ sources was estimated by applying a receptor method because identifying air emission sources were effective way to control the ambient air quality. $PM_{10}$ particles were collected from May to November 2007 in the Yongin-Suwon bordering area. $PM_{10}$ samples were collected on quartz filters by a $PM_{10}$ high-volume air sampler. The inorganic elements (Al, Mn, V, Cr, Fe, Ni, Cu, Zn, Cd, Pb, Si, Ba, Ti and Ag) were analyzed by an ICP-AES after proper pre-treatments of each sample. The ionic components of these $PM_{10}$ samples ($Cl^_$, $NO_3^-$, $SO_4^{2-}$, $Na^+$, $NH_4^+$, $K^+$, $Ca^{2+}$, and $Mg^{2+}$) were analyzed by an IC. The carbon components (OC1, OC2, OC3, OC4, OP, EC1, EC2 and EC3) were also analyzed by DRI/OGC analyzer. Source apportionment of $PM_{10}$ was performed using a positive matrix factorization (PMF) model. After performing PMF modeling, a total of 8 sources were identified and their contribution were estimated. Contributions from each emission source were as follows: 13.8% from oil combustion and industrial related source, 25.4% from soil source, 22.1% from secondary sulfate, 12.3% from secondary nitrate, 17.7% from auto emission including diesel (12.1%) and gasoline (5.6%), 3.1% from waste incineration and 5.6% from Na-rich source. This study provides information on the major sources affecting air quality in the receptor site, and therefore it will help us maintain and manage the ambient air quality in the Yongin-Suwon bordering area by establishing reliable control strategies for the related sources.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.1
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• pp.100-107
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• 2008

The objective of this study was to quantitatively estimate PM-10 source contribution in Gumi City, Korea. Ambient PM-10 samples were collected by a high volume air sampler, which operated for 84 different days with a 24-h sampling basis, from June 14,2001 though May 19, 2003. The filter samples were analyzed for determining 13 inorganic elements, 3 anions, and a total carbon. The study has intensively applied a receptor model, the PMF (Positive Matrix Factorization) model. The results from PMF modeling indicated that a total of seven sources were independently identified and each source was contributed to the ambient Gumi City from secondary sulfate (34%), motor vehicle (26%), soil relation (5%), field burning (3%), industrial relation (3%), secondary nitrate (22%), and incinration (7%) in terms of PM-10 mass, respectively.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.6
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• pp.701-717
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• 2003

The objective of this study was to extensively estimate the air quality trends of the study area by surveying con-centration trends in months or seasons, after analyzing the mass concentration of PM-10 samples and the inorganic lements, ion, and total carbon in PM-10. Also, the study introduced to apply the PMF (Positive Matrix Factoriza-tion) model that is useful when absence of the source profile. Thus the model was thought to be suitable in Korea that often has few information about pollution sources. After obtaining results from the PMF modeling, the existing sources at the study area were qualitatively identified The PM-10 particles collected on quartz fiber filters by a PM-10 high-vol air sampler for 3 years (Mar. 1999∼Dec.2001) in Kyung Hee University. The 25 chemical species (Al, Mn, Ti, V, Cr, Fe, Ni, Cu, Zn, As, Se, Cd, Ba, Ce, Pb, Si, N $a^{#}$, N $H_4$$^{+}$, $K^{+}$, $Mg^{2+}$, $Ca^{2+}$, C $l^{[-10]}$ , N $O_3$$^{[-10]}$ , S $O_4$$^{2-}$, TC) were analyzed by ICP-AES, IC, and EA after executing proper pre - treatments of each sample filter. The PMF model was intensively applied to estimate the quantitative contribution of air pollution sources based on the chemical information (128 samples and 25 chemical species). Through a case study of the PMF modeling for the PM-10 aerosols. the total of 11 factors were determined. The multiple linear regression analysis between the observed PM-10 mass concentration and the estimated G matrix had been performed following the FPEAK test. Finally the regression analysis provided source profiles (scaled F matrix). So, 11 sources were qualitatively identified, such as secondary aerosol related source, soil related source, waste incineration source, field burning source, fossil fuel combustion source, industry related source, motor vehicle source, oil/coal combustion source, non-ferrous metal source, and aged sea- salt source, respectively.ively.y.

• Korean Journal of Microbiology
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• v.40 no.2
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• pp.100-103
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• 2004

The culture condition and medium composition for the enhanced mycelial growth of Inonotus mikadoi IMSNU 32058 were investigated. The optimal temperature and pH for the mycelial growth were $27^{\circ}C$ and pH 4.5, respectively. Among the complex media tested, the malt extract medium and Phellinus igniarius medium were very good for mycelial growth of I. mikadoi. When Czapek-Dox medium was used as a minimal medium for cultivation of mycelia, xylose, raffinose and carboxymethyl cellulose were very excellent as a carbon and energy source. With respect to carbohydrate, sucrose and glucose were very good carbon sources. In general, organic complex nitrogen sources were better than other inorganic ones. As the organic complex nitrogen sources tested, yeast extract, soytone, proteose peptone and bacto peptone were the best as a source of organic nitrogen. When ammonium sulfate as an inorganic source of nitrogen was used, the enhanced mycelial growth was shown. p-Aminobenzoic acid was proved to be most appropriate source of vitamin. After the mycelia of I. mikadoi was cultivated at $27^{\circ}C$ for 5 days in MEM broth (pH 4.5), the activities of both exomycelial and endo-mycelial enzymes were determined. Among endomycelial enzymes assayed, the specific activity of laccase was much higher than those of other enzymes. When the fungus was grown in MEM broth, exomycelial specific enzyme activity of laccase was comparatively high. However, little or no enzyme activities of protease, chitinase and lipase were found.

• Korean Journal of Microbiology
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• v.47 no.3
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• pp.249-254
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• 2011

Mycophenolic acid blocking the synthesis of xanthosine monophosphate is a nonnucleoside inhibitor of inosine monophosphate dehydrogenase. Therefore mycopholoic acid is a drug currently used as immunosuppressive agent in transplantation of heart, kidney and liver. Mycophenolic acid has been industrially produced through fermentation process by fungus Penicillium brevi-compactum. In this study, the profile of mycophenolic acid fermentation was observed in 5L-jar fermentor to investigate the utilization of carbon and nitrogen sources and the production of mycophenolic acid. It was investigated that what kind of carbon sources was better to cell growth and mycophenolic acid production. Fructose was the best carbon source for mycophenolic acid fermentation, but it is the most expensive one. Thereafter molasses containing sucrose as the supply source of fructose was confirmed to be the best carbon source for the industrial production. Use of molasses increased the fermentation yield of mycophenolic acid more than two times higher than glucose. It was confirmed that urea was the best inorganic nitrogen source, which did not give rise to sudden drop of culture pH. Addition of urea increased the fermentation yield of mycophenolic acid about 3.6 times higher than addition of ammonium nitrate as control. Casein, peptone and casamino acid originated from milk protein increased the fermentation yield of mycophenolic acid about 3.4 times higher than control. Peptone and casamino acid, which are casein hydrolysates, increased cell growth considerably as well.

• Environmental Engineering Research
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• v.20 no.4
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• pp.347-355
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• 2015

The growth kinetics of phototrophic microorganisms can be controlled by the light irradiance, the concentration of an inorganic nutrient, or both. A multi-component kinetic model is proposed and tested in novel batch experiments that allow the kinetic parameters for each factor to be estimated independently. For the cyanobacterium Synechocystis sp. PCC6803, the estimated parameters are maximum specific growth rate $({\mu}_{max})=2.8/d$, half-maximum-rate light irradiance $(K_L)=11W/m^2$, half-inhibition-rate light irradiance $(K_{L,I})=39W/m^2$, and half-maximum-rate concentration for inorganic carbon $(K_{S,Ci})=0.5mgC/L$, half-maximum-rate concentration for inorganic nitrogen $(K_{S,Ni})=1.4mgN/L$, and half-maximum-rate concentration for inorganic phosphorus $(K_{S,Pi})=0.06mgP/L$. Compared to other phototrophs having ${\mu}max$ estimates, PCC6803 is a fast-growing r-strategist relying on reaction rate. Its half-maximum-rate and half-inhibition rate values identify the ranges of light irradiance and nutrient concentrations that PCC6803 needs to achieve a high specific growth rate to be a sustainable bioenergy source. To gain the advantages of its high maximum specific growth rate, PCC6803 needs to have moderate light illumination ($7-62W/m^2$ for ${\mu}_{syn}{\geq}1/d$) and relatively high nutrient concentrations: $N_i{\geq}2.3 mgN/L$, $P_i{\geq}0.1mgP/L$, and $C_i{\geq}1.0mgC/L$.