• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XII)
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• pp.213-217
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• 2003

The effects of glucose concentration on the production of PHB by fed-batch culture of Ralstonia eutropha were investigated. In the range of glucose concentration of $2.5\;{\sim}\;40\;g/l$, it was found that the high glucose concentration was not favorable for the PHB formation after the phosphate limitation. It was further confirmed by the specific PHB synthesis rates and yields. The PHB concentration decreased much with the increase of glucose concentration. But if the glucose concentration was very low, e.g. 2.5 g/l, the cell growth and PHB synthesis also could be limited because of inadequate glucose supply. Itwould be better to maintain the glucose concentration at about 9.0 g/l to obtain high DCW, PHB concentration and productivity.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XII)
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• pp.245-248
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• 2003

As a result of broth substitutions when each culture-mediums were difference, whole culture-medium was found to be best feeding solution for production of PS-7 by B. indica. Maximal production of PS-7 was 1$10.0\;g/{\ell}$ and its conversion rate from 2% (w/v) glucose to PS-7 was 50%. After 48 hr, 50%(v/v) medium of working volume began to substitute in 7L jar fermenter. Production of PS-7 increased after 48hr, recovered productivity of PS-7. Following this preliminary culture, the resultant culture was subjected to continuous flow conditions controlled that the dilution rate were $0.01\;{\sim}\;0.04\;h^{-1}$. Production of PS-7 increased at dilution rate $0.0100\;h^{-1}$ whereas productivity of PS-7 decreased gradually in dilution rate $0.0200\;{\sim}\;0.0400\;h^{-1}$. Maximal production of PS-7 was $10.0\;g/{\ell}$ in continuous culture.

• 한국식품과학회지
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• 제24권4호
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• pp.326-329
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• 1992

${\gamma}-linolenic$ acid를 함유한 유지를 생산하기 위해 포도당을 주기적으로 첨가하면서 Mucor sp. KCTC 8405P를 유가배양하였다. 배양 시작 후 2일까지 효모 모양으로 배양한 후 배지의 pH를 높여 균사체 모양으로 유도하여 배양하면, 지방질은 포도당이 고갈되는 배양 7일째까지 축적되었다. 본 배양조건에 의하여 건조 균체량 99.3 g/l, 총지방질 38.0 g/l와 3.5 g/l의 ${\gamma}-linolenic$ acid를 얻을 수가 있었다.

• 한국미생물·생명공학회지
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• 제20권6호
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• pp.663-667
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• 1992

산업적으로 산도 17.0 이상의 고산도 시초를 생산하기 위하여 반연속식인 1st stage와 유가식인 2nd stage로 구성된 two stage 초산 발효를 온도 $30^{\circ}C$, 교반속도 600rpm, 통기량 0.1vvm에서 실시하였다. 1st stage에서 초기 에탄올 농도를 $50.0g/{\ell}$, 잔류 에탄올 농도를 $5.0g/{\ell}$로 정하여 반연속적으로 초산발효를 하고, 2nd stage에서 발효시간의 경과에 따라 에탄올을 유가식으로 첨가하여 초산발효액내의 에탄올 농도를 $5.0g/{\ell}$에서 $10.0g/{\ell}$로 유지했을 때 산도가 17.6인 고산도 식초를 생산 할 수 있었으며, 또한 이때의 최대 초산 생산성은 $3.3g/{\ell}{\cdot}hr$였다.

• Journal of Microbiology and Biotechnology
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• 제10권4호
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• pp.470-475
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• 2000

Genetic chracterstics of the structural gene of guamerin (a novel elastase inhibitor from Korean leech), integrated into the HIS4 locus of chromosomal DNA of Pichia pastoris along with the $\alpha$-factor leader sequence, were investigated. In the selected clone from candidates, two copies of the integration cassette including the structural gene copies of the integration cassette including the structural gene of guamerin were found in the integration site of the chromosomal DNA of P.pastoris. It was demonstrated that the integrated structural gene of guamerin was stable up to about 70 generations in the relay flask culture. Then, a high-cell-density culture could be fulfilled easily by DO-stat fed-batch culture, in which the cell growth and the recombinant guamerin production reached about 250 of OD600nm and 260 mg/l, respectively. Finally, it was revealed that the DNA sequence of the integrated structural gene of guamerin in P. pastoris was maintained correctly in the end of production cells of relay flask culture and high-cell-density culture.

• Journal of Microbiology and Biotechnology
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• 제28권3호
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• pp.409-417
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• 2018

Biologically produced 2,3-butanediol (2,3-BDO) has diverse industrial applications. In this study, schematic isolation and screening procedures were designed to obtain generally regarded as safe (GRAS) and efficient 2,3-BDO producers. Over 4,000 candidate strains were isolated by pretreatment and enrichment, and the isolated Bacillus strains were further screened by morphological, biochemical, and genomic analyses. The screened strains were then used to test the utilization of the most common carbon (glucose, xylose, fructose, sucrose) and nitrogen (yeast extract, corn steep liquor) sources for the economical production of 2,3-BDO. Two-stage fed-batch fermentation was finally carried out to enhance 2,3-BDO production. In consequence, a newly isolated Bacillus licheniformis GSC3102 strain produced 92.0 g/l of total 2,3-BDO with an overall productivity and yield of 1.40 g/l/h and 0.423 g/g glucose, respectively, using a cheap and abundant nitrogen source. These results strongly suggest that B. licheniformis, which is found widely in nature, can be used as a host strain for the industrial fermentative production of 2,3-BDO.

• 한국미생물·생명공학회지
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• 제25권3호
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• pp.311-316
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• 1997

A high xylitol producing yeast was isolated from the sludge of xylose manufacturing factory and then identified as Candida tropicalis DS-72 according to physiological properties. The strain was able to produce xylitol in a high concentration up to 72g/l from 100g/l xylose in 32 hours. Medium optimization for xylitol production by C. tropicalis DS-72 was performed. Effect of various nitrogen sources on xylitol production was investigated. Of nitrogenous compounds, yeast extract was the most suitable organic nitrogen nutrient for the enhancement of xylitol production. However, inorganic nitrogen resulted in a low cell concentration and did not produce xylitol. Effect of inorganic salts such as KH$_{2}$PO$_{4}$, and MgSO$_{4}$, 7H$_{2}$O on xylitol production was also studied. Optimal medium was selected as xylose 100g/l, yeast extract 10g/l, KH$_{2}$PO$_{4}$, 5 g/l and MgSO$_{4}$, 7H$_{2}$O 0.2 g/l. Xylitol of 88 g/l was produced from 100 g/l xylose in 30 hours using the optimal medium in a flask. In a fermentor, a fed-batch culture with 300g/l xylose was carried out. A final xylitol concentration of 240 g/l in the culture could be obtained in 43 hours of culture time by maintaining the high level of dissolved oxygen during growth phase and limiting the dissolved oxygen in the same culture during production phase. This result corresponded to a xylitol yield of 80% and a xylitol productivity of 5.58 g/1-h.

• Journal of Microbiology and Biotechnology
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• 제16권5호
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• pp.689-694
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• 2006

We investigated the potential use of various carbon sources (fructose, glucose, mannose, lactose, and glycerol) for culturing Phaeodactylum tricornutum UTEX-640 in mixotrophic and heterotrophic batch cultures. Concentrations of carbon substrates tested ranged from 0.005 M to 0.2 M. P. tricornutum did not grow heterotrophically on any of the C-sources used, but successive additions of organic carbon in mixotrophic growth mode substantially increased the biomass concentration and productivity relative to photoautotrophic controls. The maximum biomass productivities in mixotrophic cultures for glycerol, fructose, and glucose were 21.30 mg/l h, 15.80 mg/l h, and 10.20 mg/l h, respectively. These values were respectively 10-, 8-, and 5-fold higher than those obtained in the corresponding photoautotrophic control cultures. Mannose and lactose did not significantly affect microalgal growth. The biomass lipids, eicosapentaenoic acid (EPA) and pigments contents were considerably enhanced with glycerol and fructose in relation to photoautotrophic controls. The EPA content was barely affected by the sugars, but were more than 2-fold higher in glycerol-fed cultures than in photoautotrophic controls.

• 한국미생물·생명공학회지
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• 제22권1호
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• pp.106-113
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• 1994

A novel method for production of concentrated purity maltose using swollen extruded corn starch was investigated. Degree of gelatinization of extruded starch suitable for maltose formation was found to be around 70%. The optimal amiunt of enzyme was 400 unit fungal $\alpha $-amylase per g of starch, and the reaction time was 12 hours. At extruded starch concentration of 300 g/l(w/v), maltose concentration and content were reached up to 220 g/l(w/v) and 77%(w/w), respectively. The maltose forming reaction was also successfully proceeded at high starch concentration of 700 g/l(w/v), however, the conversion yield and content were decreased. By the addition of extruded starch by fed-batch wise, the maltose concentration, purity, and conversion yield could be improved up to 465 g/l(w/v), 70%(w/w), and 0.63, respectively. The investigated maltose production process seems to have many potential advantages over the conventional process utilizing liquefied starch, and the feasibility for industrial application needs to be evaluated.

• 대한화장품학회:학술대회논문집
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• 대한화장품학회 2003년도 IFSCC Conference Proceeding Book I
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• pp.590-600
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• 2003

The matrix metalloproteinases (MMPs) are a family of enzymes responsible for degrading connective tissue. MMPs catalyze the breakdown of collagen from the extracellular matrix, leading to wrinkle formation and accelerated skin aging. Furthermore, ultraviolet irradiation causes increased expression of certain MMPs. In the extracellular matrix turnover, MMPs are interacting with endogenous regulators named tissue inhibitors of metalloproteinases (TIMPs). Using peptide substrate assays, it has been demonstrated that TIMP-MMP complexes interact highly specifically with $K_{i}$ values of 10$^{-9}$ -10$^{-16}$ M. Therefore applications for TIMP as inhibitor of collagen degradation are suggested for cosmetic anti-aging products to prevent wrinkle formation and loss of elasticity. To date four TIMP proteins (TIMP-1, TIMP-2, TIMP-3 and TIMP-4) have been identified which show a high degree in sequence similarity. The production of human TIMP-2, a 194-residue nonglycosylated protein, was performed by fed-batch culture of Escherichia coli. TIMP-2 accumulated in the bacterial cells in an insoluble form as inclusion bodies. The inclusion bodies were solubilized and the protein refolded to yield the native TIMP-2 in the active form. The integrity of the protein was confirmed by mass analysis, Edman sequencing and gel shift experiments with authentic samples. The inhibitory activity of the refolded and purified TIMP-2 was demonstrated with MMP-1 and MMP-2 assays using synthetic fluorogenic peptide substrates.s.