• Biotechnology and Bioprocess Engineering:BBE
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• v.1 no.1
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• pp.18-21
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• 1996

A continuous production of fructooligosaccharides from sucrose was investigated by fructosyltransferase immobilized on a high porous resin, Diaion HPA25. The optimum pH(5.5) and temperature(55$^{\circ}C$) of the enzyme for activity was unaltered by immobilization, and the immobilized enzyme became less sensitive to the pH change. The optimal operation conditions of the immobilized enzyme column for maximizing the productivity were as follows: 600g/L of sucrose feed concentration, flow rate of superficial space velocity 2.7h-1. When the enzyme column was run at 50$^{\circ}C$, about 8% loss of the initial activity of immobilized enzyme was observed after 30 days of continuous operation, during which high productivity of 1174g/L$.$h was achieved. The kinds of products obtained using the immobilized enzyme were almost the same as those using soluble enzymes or free cells.

• 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.

• Microbiology and Biotechnology Letters
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• v.6 no.1
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• pp.33-40
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• 1978

Immobilization of alkaline protease was investigated by absorbing the enzyme on adsorbents. Alkaline protease was adsorbed on silica gel selected as a carrier to immobilize the enzyme. In this study, properties of the immobilized enzyme were compared with those of the soluble enzyme. 1) The optimum pH (10.0) of the enzyme was not changed, but the activity was increased at alkaline pH by immobilization. 2) The optimum temperature of the immobilized enzyme was shifted from 50$^{\circ}C$ to 45$^{\circ}C$, while the temperature-activity Profile became broader than those of the soluble enzyme. 3) The pH stability of the immobilized enzyme was significantely increased at pH 4.0, althouth it did not change in the neutral and alkaline pH region. 4) The heat stability of the enzyme was enhanced in the temperature range of 55$^{\circ}C$∼65$^{\circ}C$ by the immobilization. 5) The immobilized enzyme retained 40％ of its original activity after repetitive use for 6 times. 6) The enzyme stability was greately improved for a prolonged storage at 4$^{\circ}C$.

• Archives of Pharmacal Research
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• v.3 no.1
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• pp.7-12
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• 1980

Ampliciline was synthesized from 6-amino-pencillanic acid (6-APA) and D-.alpha. phenylglycine methyl ester by using amplicilin synthesizing enzyme from Peudomonas melanogenum (IAM 1655). The whole cell enzyme was immobilized by entrapping it in the polyacrylamide gel lattices. The polymer used in the enzyme entrapment was made from 150 mg per ml of acrylamide monomer and 8 mg per ml of N, N'-methylenebisacrylamide. About 200 mg/whole cell enzyme was mixed in the polymer for entrapment. The maximal activity retention after immobilization was 56%. The optimal pH values for the whole cell enzyme and the immobilized whole cell enzyme were 6.0 and 5.9, respectively. The optimal temperature for the enzyme activity were the same for both type of preparations. The enzyme stabilities against pH and heat increased for immobilized whole cell enzyme. Immobilized cell was more stable especially in the acidic condition while both type were found to be very suceptible to thermal inactivation at a temperature above 4.deg.C. The kinetic constants obtained from Lineweaver-Burk plot based on two substate reaction mechanism showed somewhat higher value for immobilized whole cell enzyme as compared to the whole cell enzyme : the Km value for 6-APA were 7.0 mM and 12.5 mM while Km values for phenylglycine methyl ester were 4.5 mM and 8.2 mM, respectively. Using the immobilized whole cell enzyme packed in a column reactor, the productivity of ampiciline was studied by varying the flow rate of substrate solution. At the space velocity, SV, 0.14 hr$^{-1}$ the conversion was 45%. Operational stability found in terms of half life was 30 hr at SV = 0.2 hr.

• International Journal of Industrial Entomology and Biomaterials
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• v.27 no.2
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• pp.329-332
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• 2013

In present preliminary report, we showed the possibility of silk sericin (SS) in enzyme immobilization. SS beads were prepared and enzymes were immobilized on it. The specific activity of immobilized a-chymotrypsin retained more than 87% compared to the free enzyme. The immobilized a-chymotrypsin has better stability against ethanol especially those immobilized on SS beads coagulated in methanol. Immobilized trypsin and lipase had also comparable apparent activity compared to free enzyme. Our result indicates that SS could be a good candidate for enzyme immobilization support due to its hydrophilicity.

• Journal of Microbiology
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• v.44 no.3
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• pp.354-359
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• 2006

This study examined the capacity of immobilized bacteria to degrade petroleum hydrocarbons. A mixture of hydrocarbon-degrading bacterial strains was immobilized in alginate and incubated in crude oil-contaminated artificial seawater (ASW). Analysis of hydrocarbon residues following a 30-day incubation period demonstrated that the biodegradation capacity of the microorganisms was not compromised by the immobilization. Removal of n-alkanes was similar in immobilized cells and control cells. To test reusability, the immobilized bacteria were incubated for sequential increments of 30 days. No decline in biodegradation capacity of the immobilized consortium of bacterial cells was noted over its repeated use. We conclude that immobilized hydrocarbon-degrading bacteria represent a promising application in the bioremediation of hydrocarbon-contaminated areas.

• Bulletin of the Korean Chemical Society
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• v.1 no.1
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• pp.10-17
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• 1980

Penicillin amidohydrolase was partially purified from the fermented broth of Bacillus megaterium, and was immobilized on nylon fiber. The surface area of nylon fiber was increased by roughening it with fine sand and activated by acid treatment. The free amino groups on the nylon fiber exposed by such treatment were then utilized to immobilize the penicillin amidase. Enzymatic properties of penicillin amidohydrolase immobilized on the nylon fiber by covalent bonding and cross linking with glutaraldehyde were studied and compared with those of soluble enzyme. The optimal pH and temperature profile of immobilized enzyme showed only slightly broader peaks, and the values of kinetic constants, $K_m$, $K_{ia}$, and $K_{ip}$, of the immobilized enzyme are only slightly greater than those of the soluble enzyme. These results suggest that the mass transfer effect on the reaction rate for the penicillin amidase immobilized on nylon fiber is not so significant as the enzyme immobilized on some other support material like bentonite. The experimental results of batch reaction agreed well with the results of computer simulation for both the immobilized and soluble enzyme systems, confirming the validity of the rate equation derived which was based on the combined double inhibition by two reaction products.

• Bulletin of the Korean Chemical Society
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• v.30 no.1
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• pp.57-60
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• 2009

Alcohol oxidase catalyzes the oxidation of short lines alcohol to aldehyde. In this study, alcohol oxidase from Hansenula polymorpha (HpAOD) was induced by addition of 0.5% methanol as the carbon source and purified to electrophoretic homogeneity by column chromatographies. The purified HpAOD was immobilized with DEAE-cellulose particles and its biochemical properties were compared with those of free enzyme. The substrate specificity and the optimum pH of immobilized enzyme were similar to those of free enzyme. On the other hand, the Km values of free and immobilized enzymes for ethanol were 6.66 and 14.65 mM, respectively. The optimum temperature for free enzyme was ${50^{\circ}C}$, whereas that for immobilized enzyme was ${65^{\circ}C}$. Immobilized enzyme showed high stability against long storage. Immobilized enzyme was also tested for the enzymatic determination of ethanol by the colorimetric method. We detected 1 mg/liter ethanol ($1{\times}10^{-4}$% ethanol) by 2,6- dichloroindophenol system. Therefore, the present study demonstrated that immobilized HpAOD has high substrate specificity toward ethanol and storage stability, which may be of considerable interest for alcohol biosensor and industrial application.

• International Journal of Industrial Entomology and Biomaterials
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• v.27 no.2
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• pp.322-325
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• 2013

In the present study, we report that the selection of operation mode is important to take the full advantage of nanofibrous membrane in enzyme immobilization. Silk fibroin nanofibrous membrane has been prepared by electrospinning, and a-chymotrypsin was immobilized as a model enzyme. When the immobilized enzyme was operated in the membrane reactor mode, the Michaelis constant, Km, was lower and the Vmax was higher compared to the batch reactor mode. No concentration gradient was observed in the membrane reactor mode and the immobilized enzyme was stable even after 7 times of re-use. Our results suggests that the enzyme immobilized nanofibrous membrane should be operated in the membrane reactor mode rather than in the bath reactor mode.

• Journal of Microbiology and Biotechnology
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• v.20 no.2
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• pp.332-339
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• 2010

The lipase from Mucor racemosus NRRL 3631 was partially purified by fractional precipitation using 60% ammonium sulfate, which resulted in a 8.33-fold purification. The partially purified lipase was then immobilized using different immobilization techniques: physical adsorption, ionic binding, and entrapment. Entrapment in a 4% agar proved to be the most suitable technique (82% yield), as the immobilized lipase was more stable at acidic and alkaline pHs than the free enzyme, plus 100% of the original activity was retained owing to the thermal stability of the immobilized enzyme after heat treatment for 60 min at $45^{\circ}C$. The calculated half-lives (472.5, 433.12, and 268.5 min at 50, 55, and $60^{\circ}C$, respectively) and the activation energy (9.85 kcal/mol) for the immobilized enzyme were higher than those for the free enzyme. Under the selected conditions, the immobilized enzyme had a higher $K_m$ (11.11 mM) and lower $V_{max}$ (105.26 U/mg protein) when compared with the free enzyme (8.33 mM and 125.0 U/mg protein, respectively). The operational stability of the biocatalyst was tested for both the hydrolysis of triglycerides and esterification of fatty acids with glycerol. After 4 cycles, the immobilized lipase retained approximately 50% and 80% of its original activity in the hydrolysis and esterification reactions, respectively.