• KSBB Journal
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• v.9 no.4
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• pp.378-384
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• 1994

An improved method for the selective isolation of high-yielding mutant strains for the production of antifungal antibiotic KRF-001 was investigated. The mutant strain U. V 4, which produces high titer of KRF-001, was selected on the high potency agar plate after ultraviolet light irradiation. The U. V 4 strain produced 2-fold more KRF-001 than the mother strain in production media. Large scale fermentation was performed using the U. V 4 strain in 100$\ell$ fermenter. The antifungal antibiotic KRF-001 secreted into culture broth was detected by HPLC in 24hrs of fermentation.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2006.11a
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• pp.127-130
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• 2006

Coenzyme Q10(CoQ10) is a biological quinine compound that is widely found in living organisms including yeast, plants, and animals. CoQ10 has two major physiological activities:(a)mitochondrial electron-transport activity and (b )antioxidant activity. Various clinical applications are also available: Parkinson's disease, Heart disease, diabetes. Because of its various application filed, the market size of CoQ10 is continuously expanding all over the world. A Japanese company, Nisshin Pharma Inc. is the first industrial producer of CoQ10(1974). CoQ10 can be produced by fermentation and chemical synthesis. In several companies, these two methods are used for the production of CoQ10:chemical synthesis - Yungjin, Daewoong, Nishin Parma; fermentation - Kaneka, Kyowa, Yungjin, etc. Researchs in microbial production of CoQ10 have several steps: screening of producing microorganisms, strain development, fermentation process, purification process, scale-up process, plant production. Several strategies are available for the strain development : Random mutation and screening, directed metabolic engineering. For the optimization of fermentation process, various conditions (nutrient, aeration, temperature, culture type, etc.) are considered. Purification is one of the most important step because the quality of final products entirely depends on its purity. The production cost will be reduced and the quality of the CoQ10 will be impoved by continuous researches in strain development, fermentation process, purification process.

• 한국약용작물학회:학술대회논문집
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• 2006.11a
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• pp.127-130
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• 2006

Coenzyme Q10(CoQ10) is a biological quinine compound that is widely found in living organisms including yeast, plants, and animals. CoQ10 has two major physiological activities:(a)mitochondrial electron-transport activity and (b)antioxidant activity. Various clinical applications are also available : Parkinson's disease, Heart disease, diabetes. Because of its various application filed, the market size of CoQ 10 is continuously expanding all over the world. A Japanese company, Nisshin Pharma Inc. is the first industrial producer of CoQ10(1974). CoQ10 can be produced by fermentation and chemical synthesis. In several companies, these two methods are used for the production of CoQ10:chemical synthesis - Yungjin, Daewoong, Nishin Parma; fermentation - Kaneka, Kyowa, Yungjin, etc. Researchs in microbial production of CoQ10 have several steps: screening of producing microorganisms, strain development, fermentation process, purification process, scale-up process, plant production. Several strategies are available for the strain development : Random mutation and screening, directed metabolic engineering. For the optimization of fermentation process, various conditions (nutrient, aeration, temperature, culture type, etc.) are considered. Purification is one of the most important step because the quality of final products entirely depends on its purity. The production cost will be reduced and the quality of the CoQ10 will be impoved by continuous researches in strain development, fermentation process, purification process.

• Journal of Microbiology and Biotechnology
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• v.31 no.12
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• pp.1624-1631
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• 2021

Prodigiosin as a high-valued compound, which is a microbial secondary metabolite, has the potential for antioxidant and anticancer effects. However, the large-scale production of functionally active Hahella chejuensis-derived prodigiosin by fermentation in a cost-effective manner has yet to be achieved. In the present study, we established carbon source-optimized medium conditions, as well as a procedure for producing prodigiosin by fermentation by culturing H. chejuensis using 10 L and 200 L bioreactors. Our results showed that prodigiosin productivity using 250 ml flasks was higher in the presence of glucose than other carbon sources, including mannose, sucrose, galactose, and fructose, and could be scaled up to 10 L and 200 L batches. Productivity in the glucose (2.5 g/l) culture while maintaining the medium at pH 6.89 during 10 days of cultivation in the 200 L bioreactor was measured and increased more than productivity in the basal culture medium in the absence of glucose. Prodigiosin production from 10 L and 200 L fermentation cultures of H. chejuensis was confirmed by high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS) analyses for more accurate identification. Finally, the anticancer activity of crude extracted prodigiosin against human cancerous leukemia THP-1 cells was evaluated and confirmed at various concentrations. Conclusively, we demonstrate that culture conditions for H. chejuensis using a bioreactor with various parameters and ethanol-based extraction procedures were optimized to mass-produce the marine bacterium-derived high purity prodigiosin associated with anti-cancer activity.

• Journal of Microbiology and Biotechnology
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• v.33 no.10
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• pp.1257-1267
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• 2023

Although rational genetic engineering is nowadays the favored method for microbial strain improvement, building up mutant libraries based on directed evolution for improvement is still in many cases the better option. In this regard, the demand for precise and efficient screening methods for mutants with high performance has stimulated the development of biosensor-based high-throughput screening strategies. Genetically encoded biosensors provide powerful tools to couple the desired phenotype to a detectable signal, such as fluorescence and growth rate. Herein, we review recent advances in engineering several classes of biosensors and their applications in directed evolution. Furthermore, we compare and discuss the screening advantages and limitations of two-component biosensors, transcription-factor-based biosensors, and RNA-based biosensors. Engineering these biosensors has focused mainly on modifying the expression level or structure of the biosensor components to optimize the dynamic range, specificity, and detection range. Finally, the applications of biosensors in the evolution of proteins, metabolic pathways, and genome-scale metabolic networks are described. This review provides potential guidance in the design of biosensors and their applications in improving the bioproduction of microbial cell factories through directed evolution.

• Journal of Microbiology and Biotechnology
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• v.10 no.6
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• pp.770-775
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• 2000

Several process parameters were studied to ascertain the effect on degradation of sugar cane bagasse in relation to the production of cellulase enzyme and reducing sugars by Solid Substrate Fermentation (SSF) and Submerged Culture Fermentation (SCF) of Aspergillus terreus SUK-1. The effect of air-flow rate (0-1.3 v/v/m), of different ratios of substrate weight to liquid volume (1:6, 1:10, 1:20, and 1:30 w/v, g/ml), scale-up effect (10, 20, and 100 times of 1:10 ration, w/v) and the effect of temperature (30, 40, 50, and $60^{\circ}C$) in SSF were studied. Air-flow rate of 1.0 v/v/m gave the highest enzyme activity (FPase 0.25 IU/ml, CMCase 1.24 IU/ml) and reducing sugars concentration (0.72 mg/ml). Experiment using 1:10 ratio (w/v) was found to support maximum cellulase activity (FPase 0.58 IU/ml, CMCase 1.97 IU/ml) and reducing sugar concentration (1.23 mg/ml). Scaling-up the ratio of 1:10(w/v) by a factor of 20 gave the highest cellulase activity (FPase 0.71 IU/ml, CMCase 2.25 IU/ml) and reducing sugar concentration (3.67 mg/ml). The optimum temperature for cellulase activity and reducing sugar production was $50^{\circ}C$(FPase 0.792 IU/ml, CMCase 2.25 IU/ml and 3.85 mg/ml for reducing sugar concentration). For SCF, the activity of cellulase enzyme and reducing sugar concentration was found to be lower than that obtained for SSF. The highest cellulase activity obtained in SCF was 50% lower than the highest cellulase activity in SSF, while for reducing sugar concentration, the highest concentration obtained in SCF was 90% lower than that obtained in SSF.

• Membrane Journal
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• v.2 no.2
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• pp.122-128
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• 1992

A study on the citric acid production was performed in various size dual hollow fiber bioreactors with immobilized Aspergillus niger (KCTC 1232). The final dry cell mass density reached 300g/l based on the space volume available for cell growth. Under air and oxygen aeration the volumethe productivity reached 0.63 and 1.02g/l.h, which cormsponded to 10 and 16 fold over those of batch fermentation, respectively. The initial pH of the medium was a critical factor and the lower value resulted in higher citric acid yield. The increase in the feeding rate of medium or the number of reactor unit resulted in the improvement of the productivity due to higher consumption rate of substrate.

• Environmental Engineering Research
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• v.23 no.1
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• pp.46-53
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• 2018

This study explores the environmentally innovative and low-impact technology, a zero food waste system (ZFWS) that utilizes food waste and converts it into composts or biofuels and curtails carbon emissions. The ZFWS not just achieves food waste reductions but recycles food waste into fertilizer. Based on a fermentation-extinction technique using bio wood chips, the ZFWS was employed in a field experiment of the system installed in a large-scale apartment complex, and the performance of the system was examined. The on-site ZFWS consisted of three primary parts: 1) a food waste slot into which food waste was injected; 2) a fermentation-extinction reactor where food waste was mixed with bio wood chips made up of complex enzyme and aseptic wood chips; and 3) deodorization equipment in which an ultraviolet and ozone photolysis method was employed. The field experiment showed that food waste injected into the ZFWS was reduced by 94%. Overall microbial activity of the food waste in the fermentation-extinction reactor was measured using adenosine tri-phosphate (ATP), and the degradation rate of organic compounds, referred to as volatile solids, increased with ATP concentration. The by-products generated from ZFWS comply with the national standard for organic fertilizer.

• Korean Journal of Food Science and Technology
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• v.30 no.4
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• pp.908-915
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• 1998

By using Korean native soybean, traditional meju was prepared in Chuncheon, Kangweondo according to the traditional process. Analysis of physico-chemical, enzymatic and microbiological changes during meju fermentation were carried out in order to obtain a basic information for industrial scale production of meju. The enviroments for natural meju fermentation were $10{\sim}15^{\circ}C$ and $60{\sim}70%{\;}RH$. Moisture content decreased from 59% to 11% (exterior section) and 19% (interior section). the pH of meju rapidly increased up to 8.5 at $33^{rd}{\;}day$ of fermentation and thereafter decreased down to 7.9 at $70^{th}{\;}day$ of fermentation. Souble protein content was 1.47% at initial stage and increased up to $6.31{\sim}7.34%$ at $33^{rd}{\;}day$ of fermentation. Amino nitrogen content was $460{\sim}770{\;}mg%$ at $70^{th}{\;}day$ of fermentation. the color of meju became gradually black and decreased in redness and yellowness. During the process, protease and lipase seemed to play an important role in the digestion of soy protein and fat. Acidic protease activity increased up to $135.9{\sim}152.4{\;}unit/g$ at $33^{rd}{\;}day$ of fermentation and were $181.3{\sim}272.6{\;}unit/g$ at $70^{th}{\;}day$ of fermentation. Lipase activity increased up to 6 unit/g (interior section) and 15 unit/g (exterior section) at $70^{th}{\;}day$ of fermentation. the viable cell count of meju was at the level of $10^8{\;}CFU/g$ during the overall fermentation period. Aerobic halophilic count was $1.51{\times}10^7{\;}CFU/g$ at initial stage and maintained $10^8{\;}CFU/g$ level during the process. Initial anaerobic cell count was $2.0^9{\times}10^4{\;}CFU/g$ and increased up to $10^5{\;}CFU/g$ level at 47 days. Yeast and mold counts were $10^4{\sim}10^5{\;}CFU/g$ for the fermentation period.

• Natural Product Sciences
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• v.17 no.1
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• pp.19-22
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• 2011

Microbial metabolism of trans-2-dodecenal (1) was studied. Screening studies have revealed a number of microorganisms that are capable of metabolizing trans-2-dodecenal (1). Scale-up fermentation with Penicillium chrysogenum resulted in the production of two microbial metabolites. These metabolites were identified using spectroscopic methods as trans-2-dodecenol (2) and trans-3-dodecenoic acid (3).