• Applied Science and Convergence Technology
• /
• v.26 no.6
• /
• pp.157-163
• /
• 2017

Immobilized enzymes have become the subject of considerable interest due to their excellent functional properties such as reusability, cost-effectiveness, and optimality during the past decades. Enzyme immobilization technology is not only used in industrial processes, but also a component technology of products for medical diagnostics, therapy, food industry, bio energy, and biomaterial detection. In this review, new methods for enzyme immobilization are introduced, and the advantages and disadvantages of a variety of techniques in enzyme immobilization will be also discussed.

• The Korean Journal of Food And Nutrition
• /
• v.9 no.1
• /
• pp.85-91
• /
• 1996

B-amylase(EC 3.2.1.2) was isolated from the root of arrowroot(Peuria thunbergiana Bentham) with distilled water and then fractionated with ammonium sulfate. Crude extract was partially purified by ion exchange chromatography and gel filtration. The enzymatic properties of partially purified $\beta$-amylase were as follows, the enzyme was fractionated with ammonium sulfate between 0.2 and 0.4 saturation, and showed the typical reaction properties of B-amylase producing only maltose from starch. Optinum pH and temperature were pH 6.5, $50^{\circ}C$ respectively. The activity of the enzyme had proportional relations with enzyme protein concentration below 4mg, and had Michaelis constant of 66.7mg% for soluble starch. The enzyme was inhibited by some metal louts such as silver, cadmium, mercury, aluminum, iron and copper.

• Journal of Microbiology and Biotechnology
• /
• v.4 no.2
• /
• pp.134-140
• /
• 1994

An antagonistic bacterium Pseudomonas stutzeri YPL-1 liberated extracellular chitinase and $\beta$-1,3-glucanase which are key enzymes in the decomposition of fungal hyphal walls. The lytic enzymes caused abnormal swelling and retreating at the hyphal tips of plant pathogenic fungus Fusarium solani in a dual culture. Scanning electron microscopy revealed the hyphal degradation of F. solani in the regions interacting with P. stutzeri YPL-1. The production of chitinase and properties of a crude preparation of the enzyme from P. stutzeri YPL-1 were investigated. Peak of the chitinase activity was detected after 4 hr of cultivation. The enzyme had optimum temperature and pH of 50$^{\circ}C$ and pH 5.3, respectively. The enzyme was stable in the pH range of 3.5 to 6.0 up to 50$^{\circ}C$. The enzyme was significantly inhibited by metal compounds such as $HgCl_2$, but was stimulated by $CoCl_2$. P. stutzeri YPL-1 produced high levels of the enzyme after 84 hr of incubation. Among the tested carbon sources, chitin was the most effective for the enzyme production, at the concentration level of 3%. As a source of nitrogen, peptone was the best for the enzyme production, at the concentration level of 4%. The maximum amount of enzyme was produced by cultivating the bacterium at a medium of initial pH 6.8.

• Microbiology and Biotechnology Letters
• /
• v.23 no.1
• /
• pp.60-67
• /
• 1995

Methanol assimilating yeast, Hansenula sp. MS-364 that has high productivity with methanol as carbon and energy source has been preserved at dept. of Microbiological engineering. Purification and properties of alcohol oxidase (E.C.1.1.3.13: oxygen oxidoreductase) were investigated in the methanol assimilating yeast, Hansenula sp. MS-364. Alcohol oxidase is related to the catalytic reaction that degrades alcohol to aldehyde and peroxide. The methanol oxidizing enzyme was purified by ammonium sulfate precipitation, DEAE-Sephadex A-50 chromatography and gel filtration on Sepharose 6B from cell-free extract. The purified enzyme preparation gave a single band in the sodium dodesyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The molecular weight of the enzyme was calculated to be about 576,000 and molecular weight of subunit was also calculated to be 72,000. The optimal pH and temperature of the enzyme reaction were pH 7.5 and 37$\circ$C, respectively. The enzyme was unstable in acidic pH and higher temperature. The enzyme was not specific for methanol and also oxidized lower primary alcohols. The Km value for methanol was 2.5 mM and that for ethanol was 1.66 mM. The enzyme was heavily inhibited by metal ions such as Hg$^{2+}$, Ag$^{2+}$, Cu$^{2+}$. The high concentration of EDTA and sulfhydryl reagents strongly inhibited the enzyme activity. The component of coenzyme was determined to flavin adenine dinucleotide.

• Microbiology and Biotechnology Letters
• /
• v.28 no.5
• /
• pp.251-257
• /
• 2000

Serratia marcescens purine nucleoside phosphorylase (PNP) was purfied to homogeneity by streptomycin sulfate treatment, Sephacry HR S-200 gel filtration chromatography and AMP-agarose affinity chromatography. The specific activity of the enzyme was increased 49-fold during purification with an overall yield of 7.0%. The molecular weight was 168kD as estimated by Sephadex G-150 gel filtration chromatography. The S. marcescens enzyme was composed of six identical subunits with subunit molecular weight of 28kD, as estimated by SDS-PAGE. The Km values of S. marcescens enzyme for inosine and deoxyinsoine were 0.38 and 1.20 mM, respectively. The ph optimum was near 8.0, and the enzyme was relatively heat-stable protein. The enzyme was inactivated com-pletely by 0.5 mM of $Cu^{ 2+}$.

• Journal of Plant Biotechnology
• /
• v.4 no.1
• /
• pp.39-44
• /
• 2002

The fast-migrating cationic peroxidase isozyme, named RC3, was purified from rice (Oryza sativa cv. Nak-Dong) callus. Purification of the enzyme was accomplished by ammonium sulfate fractionation, CM-cellulose ionexchange chromatography, and Sephacryl S-100 gel filtration. The molecular mass of the enzyme was about 34 KDa as determined by SDS-PACE and 38 KDa by Sephacryl-100 gel filtration. The pI value of the enzyme was 8.9. Antiserum against RC3 was raised in rabbits, and anti RC3 antiserum reacted with RC3 isozyme by Ouchterlony double immunodiffusion. The optimum pHs and Km values of the enzyme for various substrates were determined. Kinetic studies with various substrates showed that RC3 had very low Km value of 0.01 mM for ferulic acid and ascorbic acid. However, the enzyme did not use esculetin as a substrate.

• KSBB Journal
• /
• v.6 no.2
• /
• pp.157-166
• /
• 1991

The structural properties of cellulose are significantly changed with the progress of hydrolysis reaction. The effects of changes on such properties of cellulosic substrate as crystallinity, amicessibility of enzyme to the active site of cellulose surface, and particle size on the kinetics of enzymatic hydrolysis have been studied. Among those physical studies, the apparent surface active site of cellulose particle was found to have the most significant effect on the hydrolysis kinetics. Based on the experimental results, the adsorption affinity of enzyme and hydrolysis rate were mainly influenced by the surface roughness of cellulose particle. The extent of accesssible active site may be expressed as the change of particle diameter. The Langmuir isotherm was proposed in terms of enzyme activity to explain the actual action of enzyme protein.

• Preventive Nutrition and Food Science
• /
• v.1 no.1
• /
• pp.53-58
• /
• 1996

The characterstics of the soy protein curd(eczyme-, HCI- and Ca-surd) were shown by scanning electron micrographs and gel electrophoreis. The emulsion stability of enzyme-curd showed high value in the range of pH 2~10and wide range of temperature(20~8$0^{\circ}C$). While at the isoelectric point(pH5.0), the emulsion stability of the HCI-and Ca-curd was decreased remarkably, and the emulsion stability of temperature was reduced quickly to the 60% and 40% at the 4$0^{\circ}C$. The foam stability of enzyme-curd was slightly higher than that HCI-and CA-curd in all ranges of pH and temperature. The feature of SEM of enzyme-cured produced degradation products faster than that of the HCI- and Ca-curd.

• BMB Reports
• /
• v.44 no.2
• /
• pp.87-95
• /
• 2011

Enzymatic catalysis has been pursued extensively in a wide range of important chemical processes for their unparalleled selectivity and mild reaction conditions. However, enzymes are usually costly and easy to inactivate in their free forms. Immobilization is the key to optimizing the in-service performance of an enzyme in industrial processes, particularly in the field of non-aqueous phase catalysis. Since the immobilization process for enzymes will inevitably result in some loss of activity, improving the activity retention of the immobilized enzyme is critical. To some extent, the performance of an immobilized enzyme is mainly governed by the supports used for immobilization, thus it is important to fully understand the properties of supporting materials and immobilization processes. In recent years, there has been growing concern in using polymeric materials as supports for their good mechanical and easily adjustable properties. Furthermore, a great many work has been done in order to improve the activity retention and stabilities of immobilized enzymes. Some introduce a spacer arm onto the support surface to improve the enzyme mobility. The support surface is also modified towards biocompatibility to reduce non-biospecific interactions between the enzyme and support. Besides, natural materials can be used directly as supporting materials owning to their inert and biocompatible properties. This review is focused on recent advances in using polymeric materials as hosts for lipase immobilization by two different methods, surface attachment and encapsulation. Polymeric materials of different forms, such as particles, membranes and nanofibers, are discussed in detail. The prospective applications of immobilized enzymes, especially the enzyme-immobilized membrane bioreactors (EMBR) are also discussed.

• Journal of the Korea Fashion and Costume Design Association
• /
• v.10 no.3
• /
• pp.173-180
• /
• 2008

Cotton, wool, cotton/wool blended (80:20) and tencel fabrics were treated with low temperature oxygen plasma, enzymes (cellulase or protease), or oxygen plasma-enzyme and they were examined for dyeing and handling properties for environment friendly finishing. The appropriate conditions for cellulase treatment were enzyme concentration of 3g/l, pH of 5, and $60^{\circ}C$ for one hour, and for protease treatment were enzyme concentration of 4g/l, pH of 8, and $60^{\circ}C$ for one hour. The equilibrium uptake of a direct dye on cotton changed with plasma treatment and plasma-cellulase treatment, and the rate of dyeing slightly decreased. When wool was dyed with acid dye, the equilibrium dye uptake did not change with plasma, protease treatment nor plasma-protease treatment, however, the rate of dyeing had increased with plasma-protease treatment. From these results, it is assumed that plasma attacks the surface of the fiber, and enzyme mainly affects the inner part of the fiber. Plasma treatment did not affect mechanical properties related to the handling of fabrics. The handling test showed increased extension at maxmum load(EM), tensile energy(WT) with decreased tensile resilience (RT), and the fabrics became softer but resilience decreased slightly with enzyme treatment. The bending recidity(B), hysteresis of bending moment(2HB), and hysteresis of shear force at five degrees(2HG5) decreased, however, shear stiffness(G) increased. I knew the plasma pre-treatment made fabrics softer with lower koshi(stiffness). The handling of plasma pre-treated fabrics was better than that of enzyme-treated fabrics. When we pre-treated fabrics, the handling test showed decreased coefficient of friction(MIU), geometrical roughness(SMD), while the surface of fabrics became smoother and numeri increased. Even though compression resilience(RC) increased, fukurami(bulky property) and compressive elasticity, decreased due to the linearity of compression-thickness curve(LC) and compression energy(WC).