• KSBB Journal
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• v.22 no.4
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• pp.185-190
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• 2007

Productivity of secreted recombinant protein depends largely on its stability in the extracellular environment with protease. Most hGM-CSF produced by transgenic tobacco cell cultures and secreted to the medium was confirmed to be rapidly degraded by protease in medium. To increase the productivity, therefore, various protein stabilizers such as gelling agents such as carrageenan and alginate, polymers, polyols, and amino acids have been tested. The stability of hGM-CSF in spent medium without cells was improved by the presence of gelling agents. However, the reason for the enhanced production by the addition of gelling agents may be due to the increased expression level and permeability rather than stability. The addition of DMSO inhibited the cell growth, but improved specific yield. The others were not effective for stability as well as hGM-CSF production.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.4
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• pp.805-809
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• 1999

The growth of Lactobacillus casei in milk was enhanced by adding yams. Addition of 1% yam(raw or dry) promoted the cell growth and acid production in fermented milk. The milk containing 1% yams formed the complete curd by lactic acid fermentation at 37oC for 19hr while the milk without yams showed the incomplete curd formation. The crude mucilage extracted from a raw yam also enhanced the cell growth as well as the acid production. Addition of mucilage(0.08%) showed the similar effects with adding heat treated yam(1%). The milk fermented by adding various yams showed the high scores for sensory evaluation comparing with the milk fermented without yams. The fermenting ability of Lactobacillus acidophilus, Lactobacillus kefir and Leuconostoc mesenteroides was evaluated by adding 1% of a dry yam in milk. A dry yam also enhanced the cell growth of L. acidophilus resulting in the high acid production. The viable cell counts of L. casei, L. acidophilus and Leuc. mesenteroides except L. kefir were increased by adding 1% of a dry yam.

• Microbiology and Biotechnology Letters
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• v.26 no.3
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• pp.195-199
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• 1998

AH alkalophilic Bacillus SP. AIk-7, isolated from soil, produced ethylene. The characteristics of this microorganism is the ability to grow well under the alkaline condition, at pH 10.3. This strain is similar to Bacillus alkalophilus in terms of morphological, physiological and biological characteristics. In observation of relationship of cell growth and ethylene production according to incubation times, the ethylene synthesis mostly occur from the late exponential phase to the death phase of growth. The purpose of this paper is to study the effects of various substrates on the biosynthesis of ethylene in the intact cell and the cell-free system by the Bacillus sp. AIk-7. In both intact cell and cell-free extract, optimum conditions for ethylene production was achieved at pH 10.3 and 3$0^{\circ}C$. Ethylene was effectively produced from L-Met and 1-aminocyclopropane-1-carboxylic acid (ACC). In this case, ACC as the substrate on ethylene production were two fold higher than L-met at each concentration of substrates. On the other hand, the cell-free ethylene-forming system was used as a tool for the elucidation of the biochemical reaction involved in the formation of ethylene by Bacillus sp. AIk-7. Ethylene production in the cell-free system required the presence of manganese and cobalt ion to be stimulated a little. The result obtained in this work suggests that L-met and ACC may be a precursor more directly related to bacterial ethylene production than any other substrates tested.

• Journal of Microbiology
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• v.41 no.3
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• pp.175-182
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• 2003

Production of ribosomally synthesized antimicrobial peptides usually referred to as bacteriocins is an inducible trait in several gram positive bacteria, particularly in those belonging to the group of lactic acid bacteria. In many of these organisms, production of bacteriocins is inducible and induction requires secretion and extracellular accumulation of peptides that act as chemical messengers and trigger bacteriocin production. These inducer peptides are often referred to as autoinducers and are believed to permit a quorum sensing-based regulation of bacteriocin production. Notably, the peptides acting as autoinducers are dedicated peptides with or without antimicrobial activity or the bacteriocins themselves. The autoinducer-dependent induction of bacteriocin production requires histidine protein kinases and response regulator proteins of two-component signal transduction systems. The current working model for the regulation of class II bacteriocin production in lactic acid bacteria and the most relevant direct and indirect pieces of evidence supporting the model are discussed in this minireview.

• Environmental Analysis Health and Toxicology
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• v.18 no.2
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• pp.95-100
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• 2003

Dichlorodiphenyltrichloroethane (DDT), is a widespread environmental pollutant. In this study, we investigated the effect of DDT on testosterone production through aromatase and investigated its molecular mechanism in testicular leydig cell, R2C. We investigated that the effects of DDT on testosterone production and its effects on aromatase activity in R2C cell by radio immunoassay (RIA). As the results, the potent leyding cell activator LH increased testosterone production compared to the control. DDT exposure significantly decreased testosterone production in R2C cell and DDT alone affected T reduction in a dose-dependent manner in R2C cell slightly. In addition, DDT was found to increase aromatase activity in R2C cell in a dose dependent manner. In order to assess whether the suppressive effects of DDT on LH-inducible testosterone production might be influenced by the ER, ICI 182.780, a pure antiestrogen, was used, and it was found that these inhibitory effects of DDT were antagonized by ICI 182.780, implying that the ER mediates the suppressive effects of DDT. Furthermore, the inducible effects of DDT on aromatase might be influenced by the ER, ICI 182.780 was used, and it was found that these enhancing effects of DDT were antagonized by ICI 182.780, implying that the ER mediates the inducible effects of DDT. Our results indicated that DDT inhibition of LH-inducible testosterone production in R2C is mediated through aromatase. However, the precise mechanisms by which DDT enhance in leyding cell remains unknown. The current study suggests the possibility that DDT might act as a modulator aromatase gene transcription.

• KSBB Journal
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• v.11 no.3
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• pp.323-328
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• 1996

Effects of three kinds of precursors as well as exogenous taxanes on the production of taxol and its derivatives were investigated in Taxus cuspidata and Taxus brevifolia cell suspension cultures. When geraniol was added as a precursor of geranylgeranyl pyrophosphate to enhance diterpenoid metabolism, production of some taxanes including taxol was enhanced. The time of addition and amount of feeding were found to be important factors. Feeding of camphor and menthol resulted in negative effects on taxol production. Influences of exogenous taxanes on taxane production by cell cultures were found to be very complicated. When taxol, baccatin III, cephalomannine were exogenously added into the culture, production of baccatin III, 7-epi-10-deacetyltaxol, 10-deacetyltaxol was increased respectively.

• Journal of Microbiology and Biotechnology
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• v.26 no.7
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• pp.1234-1241
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• 2016

Methanol is a versatile compound that can be biologically synthesized from methane (CH₄) by methanotrophs using a low energy-consuming and environment-friendly process. Methylocella tundrae is a type II methanotroph that can utilize CH₄ as a carbon and energy source. Methanol is produced in the first step of the metabolic pathway of methanotrophs and is further oxidized into formaldehyde. Several parameters must be optimized to achieve high methanol production. In this study, we optimized the production conditions and process parameters for methanol production. The optimum incubation time, substrate, pH, agitation rate, temperature, phosphate buffer and sodium formate concentration, and cell concentration were determined to be 24 h, 50% CH₄, pH 7, 150 rpm, 30℃, 100 mM and 50 mM, and 18 mg/ml, respectively. The optimization of these parameters significantly improved methanol production from 0.66 to 5.18 mM. The use of alginate-encapsulated cells resulted in enhanced methanol production stability and reusability of cells after five cycles of reuse under batch culture conditions.

• Journal of environmental and Sanitary engineering
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• v.23 no.4
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• pp.23-29
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• 2008

This study was performed to develop mutant strain using a combination of UV irradiation procedures with protoplast mutagenesis in order to achieve an effective kasugamycin production from Streptomyceskasugaensis. Whenlessthan 1.0g/lof Linoleic acid was used, the cell growth was not inhibited. On the other hand, the cell growth was greatly inhibited when more than 1.6 g/l of linoleic acid was used. Among the various mutant strains, SK-12 was obtained in medium containing 1.6g/l of linoleic acid, showing the highest rate of both cell growth and kasugamycin production. In order to compare kasugamycin production with the SK-12 and the parent strain using soybean oil, cultures were performed in a flask. The production of kasugamycin was increased with the increase time. The maximum kasugamycin concentration was 1.2g/l after 6 days of culture. The product yield from soybean oil was 0.05g/l/g consumed carbon source, which was roughly 5.0 fold higher than the parent strain. These results show that it was effective method for obtaining a mutant resistant to linoleic acid for the effective production of kasugamycin from soybean oil.

• KSBB Journal
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• v.26 no.2
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• pp.107-111
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• 2011

The essential operating parameters in virus vaccine production are multiplicity of infection (MOI), harvest time, and infection time. Stimulating agents also can be applied in order to improve vaccine productivity further. We investigated the optimum operating conditions in porcine transmissible gastroenteritis virus (TGEV) vaccine production and the applicability of sodium butyrate (NaBu) as a stimulating agents for the improvement of vaccine productivity. The optimum MOI, infection time, and harvest time for high production of TGEV by swine testicle (ST) cells were found to be 0.0001 pfu/cell, 3 day after cell inoculation, and 24 hpi, respectively. NaBu is known as a histone deacetylase inhibitor that has been widely used for the high expression of recombinant protein using mammalian cells and for the enhancement of virus propagation. So we tried to examine the potential of NaBu as a stimulating agent and to determine the optimum concentration by comparing TGEV titers with different range of NaBu concentration. TGEV titer with 5 mM NaBu was 1.5 times higher than control. Therefore, we concluded that NaBu can be a promising agent for stimulating various vaccine production including TGEV and the optimum NaBu concentration for TGEV production was determined to be 5 mM.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.478-481
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• 2006

Energy is vital to global prosperity, yet dependence on fossil fuels as our primary energy source contributes to global climate change environmental degradation, and health problems. Hydrogen $(H_2)$ offers tremendous potential as a clean renewable energy currency. Hydrogen has the highest gravimetric energy density of any known fuel and is compatible with electrochemical and combustion processes for energy conversion without producing carbon-based emission that contribute to environmental pollution and climate change. Numerous methodologies have been developed for effective hydrogen production. Among them, the biological hydrogen production has gained attention, because hydrogen can be produced by cellular metabolismunder the presence of water and sunlight. The green alga Chlamydomonas reinhardtii is capable of sustained $H_2$ photoproduction when grown under sulfur deprived condition. Under sulfur deprived conditions, PSII and photosynthetic $O_2$ evolution are inactivated, resulting in shift from aerobic to anaerobic condition in the culture. After anaerobiosis, sulfur deprived algal cells induce a reversible hydrogenase and start to evolve $H_2$ gas in the light. According to above principle, we investigated the effect of induction parameters such as cell age, cell density. light intensity, and sulfate concentration under sulfur deprived condition We also developed continuous hydrogen production system by sulfate re-addition under sulfur deprived condition.