• Applied Biological Chemistry
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• v.37 no.5
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• pp.397-401
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• 1994

Bioreduction with active dried baker's yeast proceeded smoothly in n-hexane, pentane or petroleum ether as an organic solvent system. Ethyl(1) and octyl 3-oxohexanoate(2) were reduced to $({\underline{R}})-ethyl(3)$ and $({\underline{S}})-octyl$ 3-hyroxy-hexanoate(4) with high enantiomeric excess, respectively.

• Food Science and Preservation
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• v.6 no.2
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• pp.221-227
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• 1999

The immobilized culture system of Saccharomyces cerevisiae was examined to improve the efficiency of vinegar production from persimmon juice. Optimum concentration of Na-alginate for the immobilization was 2%. When the 1eakage of yeast from get beads was checked by turbidity of culture medium with varying concentration of Na-alginate from 1 to 4%, turbidity of culture medium increased from 8 hrs of cultivation with 1% Na-alginate concentration showing optical density of 0.82 at 20 hrs. However, the increase in turbidity of culture medium was slow with 2-4% Na-alginate showing optical density of 0.55-0.58 at 20 hrs. Microscopical analysis of gel matrix showed that the immobilized yeast was grown well regardless of Na-alginate concentration. Optimum size of gel bead and amount of inoculation were 2-3 m and 33mg, respectively. For ethanol production aerobic cultivation for 121hrs using cohen plug followed by anaerobic cultivation using silicon plug equipped with a check valve was the most effective.

• Bulletin of the Korean Chemical Society
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• v.29 no.2
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• pp.381-388
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• 2008

An X-linked skeletal disorder, SEDT (spondyloepiphyseal dysplasia tarda) is a genetic disease characterized by a disproportionately short trunk and short stature caused by mutations in the SEDL gene. This gene is evolutionarily conserved from yeast to human. The yeast SEDL protein ortholog, Trs20p, has been isolated as a member of a large multi-protein complex called the transport protein particle (TRAPP), which is involved in endoplasmic reticulum (ER)-to-Golgi transport. The interaction between SEDL and partner proteins is important in order to understand the molecular mechanism of SEDL functions. We isolated several SEDL-binding proteins derived from rat cells by an immobilized GST-fusion method. Furthermore, the SEDL-homologue proteins were identified using motif based methods. Common motifs between SEDL-binding proteins and SEDL-homologue proteins were classified into seven types and 78 common motifs were revealed. Sequence similarities were contracted to seven types using phylogenetic trees. In general, types I-III and VI were classified as having the function of acetyl-CoA carboxylase, glycogen phosphorylase, isocitrate dehydrogenase, and enolase, respectively, and type IV was found to be functionally related to the GST protein. Types V and VII were found to contribute to TRAPP vesicle trafficking.

• Journal of the Korean Society of Food Science and Nutrition
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• v.18 no.1
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• pp.47-52
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• 1989

Aspergillus awamori, B-2 which has a high ability to decolorize melanoidin was selected among various fungi. Aspergillus awamori, B-2 showed the highest decolorization activity when it was cultivated in a melanoidin medium containing 3.0% glucose, 0.5% yeast extract, 0.1 % $KH_2PO_4\;and\;0.05%\;MgSO_4{\cdot}7H_2O$ at an initial pH 7.0 at $37^{\circ}C$ for 5 days. Mycelia immobilized system with. Ca-alginate was more effective on melanoidin decolorization activity showed approximately 70% in 10 days under the optimal conditions. Continuous decolorization of melanoidin using, reuse of immobilized mycelia showed an almost constant decolorization of abort 60-70% for 15 days.

• Journal of Life Science
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• v.22 no.4
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• pp.508-515
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• 2012

In this study, DEAE-cotton [derivatized by 2-(diethylamino)ethyl chloride hydrochloride (DEAE HCl)] was prepared as a carrier for immobilized $Pichia$ $stipitis$ for ethanol production. When cotton was derivatized with 0.5 M DEAE HCl, the yeast cell suspension was adsorbed at 100% of the initial cell $OD_{600}$. The adsorbed yeast cells were estimated to be 101.8 mg-dry cells/g-DEAE-cotton. In particular, when a flask culture using the immobilized yeast cells was conducted in a glucose and xylose-containing medium, the yeast cells on the DEAE-cotton gradually produced ethanol, according to glucose and xylose consumption; the ethanol yield was approximately 0.33 g-ethanol/g-monosaccharide. Because DEAE-cotton was successfully used as a carrier for ethanol production from a glucose and xylose-containing medium, we expect that this bioethanol production process may be used for the bioethanol production process from the hydrolysate of lignocellulosic biomass. All the results of DEAE-cotton were compared with those of DEAE-cellulose as a carrier for immobilization.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.8
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• pp.603-610
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• 2009

This research was performed to improve removal efficiency of toluene and methyl ethyl ketone (MEK) using Candida tropicalis, one of the yeast species. An airlift loop bioreactor (ALB) was employed to enhance the capability of mass transfer for toluene and MEK from the gas phase to the liquid, microbial phase. Polymer gel media made from PAC, alginate and PEG was applied for the effective immobilization of the yeast strain on the polymer gel media. The experimental results indicated that the mass transfer coefficient of toluene without polymer gel media was 1.29 $min^{-1}$ at a gas retention time of 15 sec, whereas the KLa value for toluene was increased to 4.07 $min^{-1}$ by adding the media, confirming the enhanced mass transfer of volatile organic compounds between the gas and liquid phases. The removal efficiency of toluene and MEK by using yeast-immobilized polymer gel media in the ALB was greater than 80% at different pollutant loading rates (5, 10, 19 and 37 g/$m^3$/hr for toluene, 4.5, 8.9, 17.8 and 35.1 g/$m^3$/hr for MEK). In addition, an elimination capacity test conducted by changing inlet loading rates stepwise demonstrated that maximum elimination capacities for toluene and MEK were 70.4 and 56.4 g/$m^3$/hr, respectively.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.468-472
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• 2003

Recently, genetic engineering techniques have been used to display various heterologous peptides and proteins (enzyme, antibody, antigen, receptor and fluorescence protein, etc.) on the yeast cell surface. Living cells displaying various enzymes on their surface could be used repeatedly as 'whole cell biocatalysts' like immobilized enzymes. We constructed a yeast based whole cell biocatalyst displaying T. reesei cellobiohydrolase I (CBH I ) on the cell surface and endowed the yeast-cells with the ability to degrade cellulose. By using a cell surface engineering system based on ${\alpha}-agglutinin,$ CBH I was displayed on the cell surface as a fusion protein containing the N-terminal leader peptide encoding a Gly-Ser linker and the $Xpress^{TM}$ epitope. Localization of the fusion protein on the cell surface was confirmed by confocal microscopy. In this study, we report on the genetic immobilization of T. reesei CBH I on the S. cerevisiae and hydrolytic activity of cell surface displayed CBH I.

• Journal of Microbiology and Biotechnology
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• v.23 no.10
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• pp.1434-1444
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• 2013

We established a two-step production process using immobilized S. cerevisiae and P. stipitis yeast to produce ethanol from seaweed (U. pertusa Kjellman) hydrolysate. The process was designed to completely consume both glucose and xylose. In particular, the yeasts were immobilized using DEAE-corncob and DEAE-cotton, respectively. The first step of the process included a continuous column reactor using immobilized S. cerevisiae, and the second step included a repeated-batch reactor using immobilized P. stipitis. It was verified that the glucose and xylose in 20 L of medium containing the U. pertusa Kjellman hydrolysate was converted completely to about 5.0 g/l ethanol through the two-step process, in which the overall ethanol yield from total reducing sugar was 0.37 and the volumetric ethanol productivity was 0.126 g/l/h. The volumetric ethanol productivity of the two-step process was about 2.7 times greater than that when P. stipitis was used alone for ethanol production from U. pertusa Kjellman hydrolysate. In addition, the overall ethanol yield from glucose and xylose was superior to that when P. stipitis was used alone for ethanol production. This two-step process will not only contribute to the development of an integrated process for ethanol production from glucose-and xylose-containing biomass hydrolysates, but could also be used as an alternative method for ethanol production.

• Korean Journal of Food Science and Technology
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• v.12 no.3
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• pp.176-181
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• 1980

Yeast invertase was immobilized on the 2 kinds of matrices : one is an indirectly coupled enzyme to the cyanogen bromide activated Sepharose by using ${\omega}-aminohexyl$ group as an extension arm, and the other is a tightly adsorbed enzyme on the modified hydrophobic cellulose derivative which has a phenoxyacetyl group as a linkage. The enzyme preparation coupled on Sepharose retained 26.0% of the original activity against sucrose as a substrate, while the preparation immobilized on phenoxyacetyl cellulose retained 72.9% . The immobilized invertase preparation on ${\omega}-aminohexyl$ Sepharose showed the optimal pH 4.5, optimal temperature $60^{\circ}C$, activation energy $5,941\;cal/mole{\cdot}deg$ and Km' 22.2 mM against sucrose, while the preparation adsorbed on phenoxyacetyl cellulose showed the optimal pH 4.0, optimal temperature $60^{\circ}C$, activation energy $7,769\;cal/mole{\cdot}deg$ and Km' 69.9 mM.

• Journal of Microbiology
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• v.43 no.3
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• pp.301-307
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• 2005

The feasibility of laccase production by immobilization of Pleurotus ostreatus 1804 on polyurethane foam (PUF) cubes with respect to media composition was studied in both batch and reactor systems. Enhanced laccase yield was evidenced due to immobilization. A relatively high maximum laccase activity of 312.6 U was observed with immobilized mycelia in shake flasks compared to the maximum laccase activity of free mycelia (272.2 U). It is evident from this study that the culture conditions studied, i.e. biomass level, pH, substrate concentration, yeast extract concentration, $Cu^{2+}$ concentration, and alcohol nature, showed significant influence on the laccase yield. Gel electrophoretic analysis showed the molecular weight of the laccase produced by immobilized P. ostreatus to be 66 kDa. The laccase yield was significantly higher and more rapid in the packed bed reactor than in the shake flask experiments. A maximum laccase yield of 392.9 U was observed within 144 h of the fermentation period with complete glucose depletion.