• Journal of Life Science
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• v.23 no.11
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• pp.1365-1370
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• 2013

Immobilized cellulase on weak ion exchange resin showed a typical Langmuir adsorption isotherm. Immobilized cellulase had better stability with respect to pH and temperature than free cellulase. Kinetics of thermal inactivation on free and immobilized cellulase followed first order rate, and immobilized cellulase had a longer half-life than free cellulase. The initial rate method was used to characterize the kinetic parameters of free and immobilized enzyme. The Michaelis-Menten constant $K_m$ was higher for the immobilized enzyme than it was for the free enzyme. The effect of the recirculation rate on cellulose degradation was studied in a recycling packed-bed reactor. In a continuous packed-bed reactor, the increasing flow rate of cellulose decreased the conversion efficiency of cellulose at different input lactose concentrations. Continuous operation for five days was conducted to investigate the stability of long term operation. The retained activity of the immobilized enzymes was 48% after seven days of operation.

• KSBB Journal
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• v.29 no.4
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• pp.239-243
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• 2014

Recently, there is a growing interest in efficient biomass pretreatment and saccharification processes to produce biofuels and biochemicals from renewable non-food biomass resources. In this study, glucose was produced from cellulose by immobilizing cellulase enzyme on chitosan beads which was reported to have high pH and temperature stability. The immobilized amounts of cellulase on chitosan beads linearly increased with increasing the concentrations of cellulase solution. The glucose production increased to 7.2 g/L from 1% carboxymethyl cellulose (CMC) substrate when immobilized at 20% cellulase solution. The maximum specific activity was 0.37 unit/mg protein when immobilized at 8% cellulase solution. At pH 7 and $37^{\circ}C$, the optimum reaction composition was 0.5 g beads/L from 1% CMC substrate. At this condition, the conversion to glucose completed at ca. 20 min.

• Preventive Nutrition and Food Science
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• v.1 no.1
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• pp.117-120
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• 1996

To enhance cellulose hydrolysis f Humicola insolens cellulase (HIC) was empolyed with immobilized glucose isomerase(IGI). Optimun pH and temperature for HIC were 6.5 and 55$^{\circ}C$, respectively, whereas those for IGI were 7.0 and 60$^{\circ}C$, respectively. Optimun loading size of IGI was 200mg(130 untis) with 15units of HIC. Reaction conditions were determined to be as follows: 55$^{\circ}C$,pH 6.5, HIC 15 units and IGI 130 units. After 24h hydrolysis, more than 65% of avicel was converted to glucose and fructose; in contrast, the conversion ratio of control was 40%.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.4
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• pp.329-333
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• 2005

This study was designed to investigate the stability of a lipase fused with a cellulose­binding domain (CBD) to cellulase. The fusion protein was derived from a gene cluster of a CBD fragment of a cellulase gene in Trichoderma hazianum and a lipase gene in Bacillus stearother­mophilus L1. Due to the CBD, this lipase can be immobilized to a cellulose material. Factors affecting the lipase stability were divided into the reaction-independent factors (RIF), and the re­action-dependent factors (RDF). RIF includes the reaction conditions such as pH and tempera­ture, whereas substrate limitation and product inhibition are examples of RDF. As pH 10 and $50^{\circ}C$ were found to be optimum reaction conditions for oil hydrolysis by this lipase, the stability of the free and the immobilized lipase was studied under these conditions. Avicel (microcrystal­line cellulose) was used as a support for lipase immobilization. The effects of both RIF and RDF on the enzyme activity were less for the immobilized lipase than for the free lipase. Due to the irreversible binding of CBD to Avicel and the high stability of the immobilized lipase, the enzyme activity after five times of use was over $70\%$ of the initial activity.

• Journal of the Korean Wood Science and Technology
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• v.38 no.3
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• pp.251-261
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• 2010

Cellulase from Formiptosis pinicola KMJ812 is an efficient cellulose degradation enzyme complex, especially with a high ${\beta}$-glucosidase activity. In this study, the change in enzymatic characteristics by immobilization and the reduction of immobilized enzyme activity by repeated usages were evaluated using cellulases from F. pinicola KMJ812. Among tested four resins, Duolite A568 resin had the best enzyme activity yield with 61.7% cellulase activity and 64.4% ${\beta}$- glucosidase activity during the cellulase immobilization. The best reaction temperature was $55^{\circ}C$ for both cellulase and ${\beta}$-glucosidase activities which were higher than the unimmobilized soluble cellulases. The best reaction pH was 4.0 for cellulase activity which was a little more basic than a soluble form and 4.5 for ${\beta}$-glucosidase activity. The immobilized cellulase activity was remained 98% of the beginning activity after 72 h incubation at $50^{\circ}C$ and 50% of the beginning activity after eight times usage at $50^{\circ}C$.

• Applied Biological Chemistry
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• v.38 no.1
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• pp.26-30
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• 1995

To produce ethanol from Jerusalem artichoke powder efficiently, Kluyveromyces marxianus FO43 cells were encapsulated in 2% sodium alginate and were cultured in batch reactor to investigate the fermentation properties. Batch culture of immobilized cells left for 4 days in 15% Jerusalem artichoke medium showed ethanol concentration of 3.38%(w/v) and ethanol yield to theoretical value of 54.20%, lower than 3.76%(w/v) and 71.13% for the culture of free cells. Addition of cellulase to $15{\sim}20%$ Jerusalem artichoke media increased the production of ethanol, owing to remarkable reduction in consistency of the suspension. So it was possible to achieve an ethanol concentration of 5.57%(w/v) arid an ethanol yield to theoretical value of 68.86% in even 20% Jerusalem artichoke medium by cultivation of immobilized cells for 4 days. The alginate beads showed constant ethanol productivity after recycling 11 times (22 days) in repeated batch fermentation.

• Microbiology and Biotechnology Letters
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• v.23 no.3
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• pp.346-351
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• 1995

To produce ethanol from Jerusalem artichoke powder efficiently, Kluyveromyces marxianus F043 cells were encapsulated in 2% sodium alginate and were cultured in a countinuous reactor to investigate the fermentation properties. Immobilized K. marxianus F043 cells were activated for 48 hours in a fermentor for continuous ethanol production. The culture in a CSTR using a Jerusalem artichoke substrate treated with 2% cellulase showed a decrease in ethanol concentration and an increase in residual saccharide concentration with a increasing dilution rate. Optimum conditions for high ethanol productivity and low residual saccharide output were clarified to be given at a dilution rate of 0.2 h$^{-1}$ and a Jerusalem artichoke medium concentration of 75 g/l. Ethanol productivity of 3.1 g/l-h and saccharide utilization of 62.6% were obtained under the optimum condition. When the fermentation was performed for 3 weeks under these conditions, the effluent medium showed stable ethanol concentrations of 16.3 - 17.9 g/l and viable cells of 6.60-7.16 log cells/ml without contamination. Trace amounts of methyl, n-propyl, iso-butyl, isoamyl alcohols besides ethanol were detected.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.10
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• pp.1417-1422
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• 2012

Alkyl glucosides were synthesized using the transglycosylation reaction of Celluclast, the cellulase from Trichoderma reesei, with cellobiose and various alcohols. Glucose as a by-product of the reaction was removed using the immobilized yeast system. Among the alkyl glucoside products, the acceptor products of methanol and ethanol were confirmed as methyl ${\beta}$-D-glucopyranoside and ethyl ${\beta}$-D-glucopyranoside via MALDI-TOF MS and enzymatic analysis. Optimal yields of methyl ${\beta}$-glucoside and ethyl ${\beta}$-glucoside were 65.3% (mol/mol) and 59.0% (mol/mol), respectively, based on cellobiose consumed.