• Proceedings of the Korean Society for Applied Microbiology Conference
• /
• 1978.10a
• /
• pp.207.2-207
• /
• 1978

Arthrobacter simplex (ATCC 6946) was cultured, induced and immobilized in acrylamide polymer. The characteristics of the immobilized whole-cell enayme were studied using hydrocortisone as the substrate. The enzyme activity was increased during the incubation of the gel particle in 0.5％ peptone media. The ennzyme reaction kinetics of the Δ'-dehydrogenase (3-oxosteroid Δ'-oxydo reductase, E. C. 1.3.99.4) foliowed the Michaelis-Menten type. Km and Vm values were different significantly after immobilization of the cell. The optimum pH and temperature were changed, too. Nitrogen sources such as casitone, peptone or tryptone were good media for the enzyme reaction. And there was no need to add cofactors of the enzyme in the pre-sence of energy sources used in the test. The effect of metal ions on the enzyme activity was insignificant. Organic solvents were used increase the substrate concentration and there was no optimum solvent concentration depending on the substrate concentration.

• KSBB Journal
• /
• v.13 no.4
• /
• pp.411-417
• /
• 1998

The possibility of application of membrane type immobilized adsorbent to the fed-batch or perfusion culture system with anchorage-independent cells as well as batch system was investigated. The improvement in cell density and cell viability due to the combination of immobilized adsorbent with each culture system was evaluated for the investigation, and the optimum culture system employing immobilized adsorbent system was suggested based on the results. It was observed that the system with immobilized adsorbent showed better cell growth and cell viability than that without immobilized adsorbent in every operation system of batch, fed-batch, and perfusion. In case of batch system, 200% improvement of maximum cell density was observed in the system where ammonium chloride was added on purpose. And 50% improvement of maximum cell density was observed in the fed-batch system where ammonium ion accumulates significantly, while small increase in maximum cell density was observed in the perfusion system where dilution of waste byproducts exists. Especially, the fed-batch system showed the most significant improvement on cell growth because both compensation of nutrient and removal of ammonium ion occurred simultaneously in the system. Therefore a combined system of immobilized adsorbent and fed-batch operation could be suggested as an optimum system with in situ removal of ammonium ion.

• Journal of Microbiology and Biotechnology
• /
• v.7 no.1
• /
• pp.62-67
• /
• 1997

To enhance the hyperproductive and low energy-consuming ethanol fermentation rate, the thermotolerant yeast S. cerevisiae RA-74-2 cells were immobilized. An efficient immobilization condition was proved to be $1.5{\%}$ (w/v) alginate solution, neutral pH and 20 h activation of beads. The fermentation characteristics and stability at various temperatures were examined as compared with free S. cerevisiae RA-74-2 cells. The immobilized cells had excellent fermentation rate at the range of pH 3-7 at 30-$42^{\circ}C$ in 15-$20{\%}$ glucose media. When the seed volume was adjusted to 0.12 (v/v) (6ml bead/50 ml medium), $11{\%}$ (w/v) ethanol was produced during the first 34 hand $12.15{\%}$ (w/v) ethanol [$95{\%}$ (w/v) of theoretical yield] during the first 60 h in $25{\%}$ glucose medium. In repetitive fermentation using a 2 litre fermentor, 5.79-$7.27{\%}$ (w/v) ethanol [76-$95{\%}$ (w/v) of theoretical yield] was produced during the 40-55 h in $15{\%}$ glucose media. These data suggested the fact that alginate beads of thermotolerant S. cerevisiae RA-74-2 cells would contribute to economic and hyperproductive ethanol fermentation at high temperature.

• KSBB Journal
• /
• v.23 no.4
• /
• pp.350-354
• /
• 2008

Magnetically separable immobilized trypsin was developed and their biocatalytic activity was evaluated for the different immobilization media. The activity, recyclability, pH effect, and stability of immobilized enzymes were evaluated for the different supporting media. The biocatalytic activity of immobilized trypsin was highest with magnetically separable polyaniline (PAMP), and Vm and Km of PAMP were 0.169 mM/min and 0.263 mM respectively. With increasedpH, the biocatalytic activity increased for all supporting materials used. Immobilized enzymes were recycled and recycle activities were over 90% of their original activity after ten times reuse. The operational stabilities of enzymes were greatly improved with enzyme immobilization.

• Journal of Microbiology and Biotechnology
• /
• v.5 no.4
• /
• pp.229-233
• /
• 1995

Acremonium chrysogenum was immobilized in ionotropic gel beads to develop semi-continuous production of cephalosporin C (CPC). Barium alginate beads were more stable than calcium alginate or strontium alginate beads in chemically defined media. The gel stability of Ba-alginate was further increased by cross-linking with polyethyleneimine (PEI). The presence of carboxymethyl cellulose inside Ba-alginate beads did not reduce mass transfer resistance. Ba-alginate microbeads that had little diffusion limitation increased CPC production rate 1.6 fold higher than that of normal beads. CPC fermentation with immobilized cells in Ba-alginate microbeads was performed continuously for 40 days by way of repeated fed-batch operations. Mathematical modeling was developed to describe the repeated fed-batch fermentation system. Results of the computer simulation agreed well with the experimental data, which made it possible to predict an optimal feeding rate that could maximize total CPC productions.

• Journal of Korean Society on Water Environment
• /
• v.31 no.1
• /
• pp.42-48
• /
• 2015

This study focused on effective decomposition methods for low concentrated organic compounds from the reuse of industrial wastewater, and confirmed the possibility through photocatalyst media. Photocatalyst immobilized media was developed to carry on this experiment which confirmed the removal possibility of low concentrated organic compounds. Considering the stability and efficiency of photocatalyst immobilization, inorganic support, hollow bead, and $TiO_2$ nano powder were used. As a result of the removal experiment, the removal efficiencies of acetonitrile, ethanol, IPA(Isopropyl alcohol), methanol were above 75% after 15 minutes while those of acetone, acetaldehyde, urea were 10%, 45%, 20%, respectively after 60 minutes. If further studies were made to increase the surface area of the photocatalyst immobilized media, the efficiency of the removal of low concentrated organic compounds can be improved and this solution can also be used in an actual treatment process.

• KSBB Journal
• /
• v.15 no.5
• /
• pp.438-443
• /
• 2000

Continuous processes using immobilized yeast were investigated in order to shorten beer maturation time. Three silica-based ceramic media and one cellulose-based medium were used. Diacetyl (DA) was one of the most distinctive compounds causing immature flavors. Heat treatment of green beer (GB) to convert a-acetolactate to DA was essential to shorten the time for beer maturation. The longer heat treatment time was needed at the lower temperature. Oxygen concentration in GB had a large influence on the conversion of a-acetolactate to DA. The lower the oxygen concentration in GB, the lower conversion ratio to DA. Heat treated GB was fed continuously to four kinds of immobilized yeast columns. DA concentration after immobilization columns was reduced to less than 0.1ppm at $3∼5^{\circ}C$ 180∼150 minutes retention time in all columns tested. This concentration is enough to fit the quality speification of commercialized product. Formation of a-acetolactate from residual sugars was higher in ceramic media column than cellulose media cloumn. The taste of beers from test processes were not the same as that of traditionally produced beer, but no off-flavors were detected in test samples, which shows that immobilized yeast columns have potentials as rapid processes for beer maturation.

• KSBB Journal
• /
• v.10 no.3
• /
• pp.231-236
• /
• 1995

For continuous ethanol production In an immobilized cell reactor consisting of Saccharomyces sake, feedings of one tenth to three tenths times diluted fermentation media were effective for maintaining the high ethanol productivity and physical stability of immobilized beads. In case two tenths times dilltued one of the fermentation medium supplemented with egg albumin hydrolysate(0.5%) and phosphatidylcholine(0.5%) was fed, a maximum ethanol productivity of $69 g/\ell$-hr was attained at a dilution rate of$1.1lhr^{-1}$, and it was 50% higher than that of the two tenths times diluted one of the fermentation medium without any supplement, $46 g/\ell$-hr.

• KSBB Journal
• /
• v.25 no.4
• /
• pp.351-356
• /
• 2010

To increase the production of ethanol by using sugar from lignocellulosic biomass, pentose and hexose have to be fermented simultaneously by yeast. The effects of mixed sugar and nitrogen on ethanol production by immobilized Pichia stipitis KCCM 12009 were investigated. When optimal mixed sugar and nitrogen concentration were 5% (Glucose/Xylose = 3:1) and 1%, respectively, ethanol concentration produced by immobilized P. stipitis was 19-20 g/L. In repeated fed-batch by immobilized P. stipitis, all glucose was consumed very quickly at 1-3% mixed sugar concentration. But, xylose consumption was decreased as the mixed sugar concentration increased. Also, ethanol (5.6 g/L) was stably produced and ethanol production rate was 0.13 g/$L{\cdot}h$ in immobilized cell reactor (ICR) with 1% mixed sugar (Glucose/Xylose = 3:1) as feeding media.

• KSBB Journal
• /
• v.13 no.4
• /
• pp.404-410
• /
• 1998

Three types of adsorbents were developed by immobilizing synthetic zeolite, Philipsite-Gismonine, in alginate, cellulose acetate and dialysis membrane for the in situ removal of ammonium ion which inhibits growth and productivity of animal cells such as CHO cells producing tPA. Ammonium ion removal efficiency and cell growth promoting effect with various immobilized adsorbents were evaluated and the membrane type was selected as an optimal immobilized adsorbent. The experiments were then simulated by adding 8mM ammonium chloride and immobilized adsorbent in order to validate the removal effect under high density cell cultures. The results showed increase in maximum cell density by three times, in cell viability, and in tPA productivity by 40%. And it was found that the promoting effects were more significant in case of high ammonium ion concentration system. It was also found that the optimum addition time for immobilized adsorbents was 48 hr in the absence of ammonium chloride addition and 72 hr in the presence of ammonium chloride addition.