• Microbiology and Biotechnology Letters
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• v.18 no.1
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• pp.66-70
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• 1990

A study on 11 $\alpha$-hydroxylation of progesterone by using Rhizopus nigricans was carried out to produce efficiently 11 $\alpha$-hydroxyprogesterone which is an essential intermediate of corticosteroids synthesis. Firstly, medium was optimized in view of bioconversion yield and cell growth. Glucose and casamino acid were selected as carbon and nitrogen source and the ratio of carbon to nitrogen which maximize bioconversion yield was determined to be 2:1. Secondly, the addition time of progesterone and dispersion method were studied. When progesterone dispersed with 0.01% (v/v) Tween 80 was added at 12-14 hr of cultivation, higher bioconversion yield was obtained. When 20g/$\ell$ of progesterone was added, the yield reached 70% under optimized conditions.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.399-402
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• 2002

Industrial wastewater with high ammonium concentration was treated in batch biological systems which was a modified Ludzack- Ettinger process. Up to 78% conversion of $NH_4\;^+-N$ to $NO_x\;^--N$ was achieved in batch culture condition. Under anoxic condition with methanol as the carbon source, the denitrifiers decreased $NO_x\;^--N$ concentration from 608 mg/L to 5.6 mg/L in 22 d. As well as anoxic denitrification of $NO_x\;^-$ to $N_2$, dissimilatory nitrate reduction to ammonium also occurred under the condition as respiratory denitrification.

• Journal of environmental and Sanitary engineering
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• v.16 no.1
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• pp.108-116
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• 2001

It is difficult to task to achieve high biological nutrient removal from municipal wastewater because of low organic content. Volatile fatty acids(VFAs) produced from acid fermentation of food wastes can be utilized as external carbon sources for the biological nutrient process. Significant reduction and stabilization of the food wastes can also be obtained from the acid fermentation. The objective of this study is to evaluate characteristics of acid fermentation of the food wastes. Results obtained from the batch experiment of various organic wastes showed that the food wastes had high potential to be used as an external carbon source because of the largest production of the VFAs with low nitrogen and phosphorus content. The fish waste was found to be the next possible organic waste, while the others such as radish cabbage and molasses waste showed high VFAs consumption potential as a results of high nitrogen and phosphorus content. alkaline hydrolysis of the food waste was carried out using NaOH prior to the acid fermentation. As the alkali addition increased, solubilization of the organics as well as TSS reduction increased. However, fraction of soluble COD to total COD became stable after a sharp increase. Alkali addition greater than 0.5g NaOH per g TS resulted in significant increase in pH.

• Journal of Environmental Science International
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• v.16 no.6
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• pp.707-714
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• 2007

A laboratory experiment was performed to investigate nitrogen removal by the soil column. The addition of 20% waste oyster shell to the soil accelerated nitrification in soil column. The $NO_3^--N$ concentration in the effluent decreased with the decrease of HRT(Hydraulic Retention Time). When methanol and glucose added as carbon sources, the average removal rates of T-N(Total Nitrogen) were 82% and 77.9%, respectively. The $NO_3^--N$ removal by methanol supplementation in soil column can likely be attributed to denitrification. In continuous removal of nitrogen using the soil column, the COD(Chemical Oxygen Demand) and $NH_4^+-N$ removed simultaneously in organic matter decomposing column. The greater part of $NH_4^+-N$ was nitrified by the percolated through nitrification column, and the little $NH_4^+-N$ was found in the effluent. The T-N of 87.4% removed at HRT of 36 hrs in denitrfication column. Because of nitrified effluents from nitrification column are low in carbonaceous matter, an external source of carbon is required.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.557-562
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• 2005

The field scale experiment was performed to examine the effect of plant coverage on the constructed wetland performance and recommend the optimum development and management of macrophyte communities. Four sets(each set of 0.88ha) of wetland (0.8ha) and pond(0.08ha) systems were used. Water flowing into the Seokmoon estuarine reservoir from the Dangjin stream was pumped into wetland system. Water depth was maintained at $0.3{\sim}0.5m$ and hydraulic retention time was managed to about $2{\sim}5$ days; emergent plants were allowed to grow in the wetlands. After three growing seasons of the construction of wetlands, plant coverage was about 95%, even with no plantation, from bare soil surfaces at the initial stage. Dead vegetation affected nitrogen removal during winter because it is a source of organic carbon which is an essential parameter in denitrification. Biomass harvesting is not a realistic management option for most constructed wetland systems because it could only slightly increase the removal rate and provide a minor nitrogen removal pathway due to lack of organic carbon.

• KSBB Journal
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• v.20 no.1 s.90
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• pp.26-33
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• 2005

The effects of carbon sources for exopolysaccharide production during batch cultivation of an Enterobacter sp. isolated from the composter were investigated. The highest amount of exopolysaccharide was obtained when lactose was used as carbon source. Lactose in medium was converted into glucose and galactose. Glucose was metabolized fast and was completely consumed, but about $20\%$ of lactose was accumulated as galactose. On the other hand, enzyme activity was about $350\~450$ unit with the increase of lactose concentration. Thus, it was considered that the exopolysaccharide might be produced in the course of that lactose was hydrolyzed into glucose and galactose by $\beta-galactosidase$ with respect to that enzyme activity on lactose hydrolysis was accorded to the exopolysaccharide production. When glucose and galactose were added to lactose medium, respectively, it could be considered that glucose was as a repressor and galactose was as a inducer for $\beta-galactosidase$ synthesis even though the mechanisms were not elucidated. The increase of lactose concentration was almost ineffective to the specific growth rate $(0.133\~0.151\;hr^[-1})$ but showed the difference in the biomass content. The higher carbon source concentration, the more residual sugar remained. It was assumed that the optimum lactose concentration for exopolysaccharide production was $30\~70g/L.$ On the other hand, it was considered that the nitrogen acted as growth limiting nutrients to the cell growth. In the cases of 30 and 70 g/L of the fixed carbon concentrations, the increase of the nitrogen sources concentration caused a remarkable increase within the range of $0.059\~0.225\;hr^{-1}$ and $0.141\~0.237hr^{-1}$ of the specific growth rate, respectively, while there was no significant difference in biomass.

• Journal of Microbiology and Biotechnology
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• v.13 no.1
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• pp.1-8
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• 2003

Strain FJI, a filamentous fungus isolated from rotten wood, showed high ability to hydrolyze cellulosic materials. To identify the strain FJI, ITS sequencing analysis and morphological observation were performed. The strain FJI was identified as Trichoderma harzianum. The strain produced a large amount of CMCase, xylanase, ${\beta}-glucosidase$, and avicelase. Optimal culture conditions for the production of the enzymes, such as pH, temperature, and inoculation concentration, were initial pH 6.0-7.0,$25-30^{\circ}C$, and $10^4$ ea-spores/ml in Mandel's medium, respectively. T.hanzianum FJI utilized various cellulosic materials and organic nitrogen sources to produce cellulases and xylanase, and also considerably a crystalline and/or insoluble material like Avicel and rice straw. The highest levels of CMCase and xylanase were 41.2 and 65.6 U/ml in 7 days of cultivation using 2.5% of carbon source (Avicel+CMC) and 0.5% of nitrogen source (peptone), respectively.

• Journal of Environmental Science International
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• v.16 no.1
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• pp.45-53
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• 2007

This study was carried out to investigate the variation of organic, nitrogen and phosphorus in $(AO)_2$ SBBR process according to the variation of operating cycle at the high TOC concentration. The operation time in anoxic (anaerobic) time to oxic time was 1:1. Three lab-scale SBBRS were fed with synthetic wastewater based on glucose as carbon source, The variation of total TOC removal was similar each other irrespective of operation time, however, the TOC concentrations in SBBRs showed a little difference according to the operating condition. In SBBR, complete nitrification was not occurred at all reactors, however, R3 showed a higher nitrification than R2. And in SBBR, the variation of operating time more affected at phosphorus removal than nitrogen removal. R2 which had the shortest time at the 1st aeration time showed the lowest phosphorus release and uptake efficacy.

• Journal of Microbiology and Biotechnology
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• v.20 no.5
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• pp.950-957
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• 2010

Serratiopeptidase (SRP), a 50 kDa metalloprotease produced from Serratia marcescens species, is a drug with potent anti-inflammatory property. In this study, a powerful statistical design, evolutionary operation (EVOP), was applied to optimize the media composition for SRP production in shake-flask culture of Serratia marcescens NRRL B-23112. Initially, factors such as inoculum size, initial pH, carbon source, and organic nitrogen source were optimized using one factor at a time. The most significant medium components affecting the production of SRP were identified as maltose, soybean meal, and $K_2HPO_4$. The SRP so produced was not found to be dependent on whey protein, but rather was notably induced by most of the organic nitrogen sources used in the study and free from other concomitant protease contaminant, as revealed by protease inhibition study. In addition, experiments were performed using different sets of EVOP design with each factor varied at three levels. The experimental data were analyzed with a standard set of statistical formula. The EVOP-optimized medium, with maltose 4.5%, soybean meal 6.5%, $K_2HPO_4$ 0.8%, and NaCl 0.5% (w/v), gave a SRP production of 7,333 EU/ml, which was 17-fold higher than the unoptimized media. The application of EVOP resulted in significant enhancement of SRP production.

• Journal of Life Science
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• v.11 no.2
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• pp.173-180
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• 2001

This study was conducted to estimate the cultural characteristics, the production of antibiotic, and the selection of optimal media for mass culture of Bacillus licheniformis N1 isolate which was previously reported as an antagonistic bacterium to Botrytis cinerea. We investigated initial pH, temperatures and shaking speed for good cultural conditions and antibiotics production by N1 isolate. According to the results, the optimal conditions of initial pH, temperatures, and shaking speed were determined to be pH 5.0~5.5, 30~35$^{\circ}C$ and 250 rpm, respectively. Also, the optimal conditions for the antagonism by N1 isolate highly appeared in the initial pH as 5.0, and the mycelial growth inhibition was high when the substances used such as glucose or corn starch as carbon sources, and biji(soybean curd residue) flour as a nitrogen source. Furthermore, inhibitory area was significantly expanded, when 3% or 5% of corn starch was added into 5% of Biji flour as nitrogen source, were respectivley selected for mass culture of N1 isolate. Among them, 5% Biji flour medium showed higher cell density more than 10 times that in NB medium after 48 hour incubation. Therefore, the optimal medium was determined as 5% biji flour added 3~5% of corn starch for high density of cells.