• Journal of Microbiology and Biotechnology
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• v.20 no.7
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• pp.1086-1091
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• 2010

This study explored the use of gellan gum as an immobilization matrix for the production of cyclosporin A (CyA) by immobilized spores and mycelia of Tolypocladium inflatum MTCC 557. Different carriers, such as gellan gum, sodium alginate, celite beads, and silica, were tested as immobilization carriers, along with the role of the carrier concentration, biomass weight, number of spore-inoculated beads, and repeated utilization of the immobilized fungus. The maximum CyA production was 274 mg/l when using gellan gum [1% (w/v)], and a mycelial weight of 7.5% (w/v) supported the maximum production of CyA. Additionally, the addition of a combination of $_L$-valine (6 g/l) and $_L$-leucine (5 g/l) after 48 h of fermentation produced 1,338 mg/l of CyA when using gellan gum. The immobilized mycelia beads were found to remain stable for four repetitive cycles, indicating their potential for semicontinuous CyA production.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.35 no.2
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• pp.39-45
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• 2003

This study was performed to develop the new type enzyme immobilization sheet from carboxymethylated refiner mechanical pulp (CRMP) substrate. Enzyme immobilization was attempted to couple carboxyl groups of CRMP with amino groups of the enzyme, trypsin, through the reaction of carbodiimide reagent, 1-ethyl-3-(3-dimethyl aminopropyl)-carbodimide (EDC ). Immobilization carrier, water insoluble CRMP fraction (CRMP-IS), was successfully reacted with the enzyme, formed peptide linkage like -CONH- at 1680$cm^{-1}$ / and new ester linkage like -COO$CH_3$, methylester at 1735$cm^{-1}$ /, and produced enzyme immobilized substrate (CRMP-IST). The enzyme immobilized handsheet was prepared by mixing the above chelated enzyme immobilized substrate(CRMP-IST) with kraft pulp by paper sheet machine like papermaking process. The sheet weight and strength were increased with increasing dosage of CRMP-IST, and decreased at more than 10％ mixing of CRMP-IST, but higher than the controls. Concerning activities of immobilized trypsin(CRMP-IST) sheet by caseinolysis, the teared-off sheet with shaking was shown higher enzyme activities than sheet shape without shaking. In conclusion, this enzyme immobilized sheet would be expected easy handling for practical application and reutilization.

• Journal of Microbiology and Biotechnology
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• v.27 no.4
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• pp.768-774
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• 2017

Horseradish peroxidase (HRP) catalyzes the oxidation of aromatic compounds by hydrogen peroxide via insoluble polymer formation, which can be precipitated from the wastewater. For HRP immobilization, poly(lactic-co-glycolic acid) (PLGA) fine carrier supports were produced by using the Nano Spray Dryer B-90. Immobilized HRP was used to remove the persistent 2,4-dichlorophenol from model wastewater. Both extracted (9-16 U/g) and purified HRP (11-25 U/g) retained their activity to a high extent after crosslinking to the PLGA particles. The immobilized enzyme activity was substantially higher in both the acidic and the alkaline pH regions compared with the free enzyme. Optimally, 98% of the 2,4-dichlorophenol could be eliminated using immobilized HRP due to catalytic removal and partly to adsorption on the carrier supports. Immobilized enzyme kinetics for 2,4-dichlorophenol elimination was studied for the first time, and it could be concluded that competitive product inhibition took place.

• Microbiology and Biotechnology Letters
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• v.19 no.2
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• pp.171-178
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• 1991

The two-stage enzyme reactor, packed with cyclodextrin glucanotransferase (CGTase) immobilized on Amberite IRA 900, coupled with ultrafiltration membrane was investigated for continuous production of cyclodextrin (CD). 5% (w/v) of soluble starch was partially cyclized, in the 0.1 l first-stage immobilized enzyme reactor, up to CD conversion yield of 10% (w/w) at retention time of 0.56hr and 1.5 units of immobilized CGTase/1g of carrier. In the second stage main immobilized enzyme reactor capacity of 1.5 l, the maximum CD conversion yield of 39% (w/v) was achieved at retention time of 2.8hr and 0.47 unit of CGTase/1 g of carrier. Unreacted residual dextrin was fractionated with ultrafiltration membrane, and then, recycled into the second-stage main bioreactor to increase the CD conversion yield. The most suitable membrane size and the volume concentration ratio (concentrate: filterate) for recycling of unreacted residual dextrin were found to be 5K dalton and 4:6, respectively. CD conversion yield was increased about 3~4% upon co-immobilization of pulluanase along with CGTase. Spent Amberite IRA 900 can be reutilized consecutively more than 3 times for immobilization of CGTase after regeneration.

• KSBB Journal
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• v.11 no.6
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• pp.649-653
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• 1996

Imnmobilization characteristics of Thiobacillus sp. IW which oxidizes sulfur compound was studied to use the bacterium in odor controlling equipment for the future. The optimum growth conditions for Thiobacillus sp. IW were pH7, $30^{\circ}C$ and the generation time was 38min, which was extremely fast compared with other sulfur oxidizing bacteria. Optimum growth conditions in activated carbon as a carrier was pH5, $35^{\circ}C$ and those in bioceramics was pH 7∼8, $35^{\circ}C$. Cell growth immobilized in bioceramics was more stable in pH, temperature change than that immobilized in activated carbon and total number of cells in bioceramics were also higher. Based on these results, the bioceramics is thought to be better carrier in immobilization of Thiobacillus sp. IW.

• Journal of Microbiology and Biotechnology
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• v.20 no.1
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• pp.110-116
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• 2010

Lactic acid (LA) fermentation by Lactobacillus salivarius ATCC 11741 immobilized on loofa sponge (LS) was evaluated. To increase the surface area of LS for cell immobilization, $H_2O_2$ and chitosan were introduced as surface modifying reagents. Four chitosans of different molecular weights were separately coated on LS. All experiments were conducted in shaking flask mode at 100 rpm rotating speed and $37^{\circ}C$ with 5% $CaCO_3$ as a pH regulating agent. The effects of initial glucose concentration were investigated in the range of 20-100 g/l on LA fermentation by free cells. The results indicate that the maximum concentration of LA was produced with 50 g/l glucose concentration. The immobilized cell system produced 1.5 times higher concentration than free cells for 24 h of fermentation. Moreover, immobilized cells can shorten the fermentation time by 2-fold compared with free cells at the same level of LA concentration. At 1% (w/v) chitosan in 2% (v/v) acetic acid, the Yp/s and productivities of various molecular weights of chitosans were insignificantly different. Repeated batch fermentations showed 5 effective recycles with Yp/s and productivity in the range of 0.55-0.85 and 0.90-1.20 g/l.h, respectively. It is evident that immobilization of L. salivarius onto LS permits reuse of the system under these fermentation conditions. Scanning electron micrographs indicated that there were more intact cells on the chitosan-treated LS than on the untreated LS, thus confirming the effectiveness of the LS-chitosan combination when being utilized as a promising immobilization carrier for LA fermentation.

• Bulletin of the Korean Chemical Society
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• v.34 no.9
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• pp.2741-2746
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• 2013

The immobilization of enzyme is one of the key issues both in the field of enzymatic research and industrialization. In this work, we reported a facile method to immobilize Candida Antarctica lipase B (CALB) in alginate carrier. In the presence of calcium cation, the enzyme-alginate suspension could be cross-linked to form beads with porous structure at room temperature, and the enzyme CALB was dispersed in the beads. Activity of the enzyme-alginate composite was verified by enzymatic hydrolysis reaction of p-nitrophenol butyrate in aqueous phase. The effects of reaction parameters such as temperature, pH, embedding and lyophilized time on the reactive behavior were discussed. Reuse cycle experiments for the hydrolysis of p-nitrophenol butyrate demonstrated that activity of the enzyme-alginate composite was maintained without marked deactivation up to 6 repeated cycles.

• Applied Chemistry for Engineering
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• v.16 no.2
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• pp.200-205
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• 2005

We have prepared the porous carrier that has high capacity for immobilization of microorganisms and adsorption capacity for cation using fly ash in the previous work. In this study, we investigated the characteristics of piggery wastewater treatment in comparison with commercial carrier and conventional activated sludge process by continuous-flow fixed biofilm process in laboratory scale at the same experimental conditions to develop the biofilm process using porous fly ash carrier for wastewater treatment. As a result, the prepared fly ash carrier showed that removal efficiency of COD, TN and $NH_4{^+}-N$ items were 80%, 77% and 65%, respectively, which were higher efficiency than the commercial carrier and conventional activated sludge process. And the result of measurement for immobilized microorganisms after treatment showed higher capacity than the commercial carrier, and it was confirmed by SEM observation on fly ash carrier that the colony of microorganisms was stably formed.

• Clean Technology
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• v.8 no.3
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• pp.167-172
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• 2002

The adaptability of earthworm casts produced form the waste sludge of pulp and paper plants for a biocarrier used in the advanced wastewater treatment was investigated. Removal efficiencies of nutrients in the activated sludge technology without carrier were compared with those treated with carrier made of casts under the different conditions such as the composition of the input and kinds of carrier. When the waste water was treated in the activated sludge technology without carriers, removal efficiencies of T-P and T-N were average values of 31% and 52%, respectively. On the contrary, pellet type carrier and pack type carrier increased the removal efficiencies of T-P and T-N by 1.3~1.4 and 1.9~2.0 times, respectively. At the same time, the high removal of T-P and T-N were observed irrespective of the types of carrier in which many kinds of microorganisms were grown. The difference in the removal efficiencies of BOD and COD between the treatment with and without carrier was negligible. According to this research, the carrier made of casts was thought to be highly applicable in the advanced wastewater treatment.

• 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.