• Analytical Science and Technology
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• v.29 no.3
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• pp.105-113
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• 2016

The present study investigated the immobilization of lipases on silica nanoparticles and silica-coated magnetite nanoparticles as supports with a functional group to enhance the stability of lipase. The influence of functional groups, such as the epoxy group and the amine group, on the activity and stability of immobilized lipase was also studied. The epoxy group and the amino group were introduced onto the surface of nanoparticles by glycidyl methacrylate and aminopropyl triethoxysilane, respectively. Immobilized Candida rugosa lipase on silica nanoparticles and silica-coated magnetite nanoparticles with a functional group showed slightly lower initial enzyme activities than free enzyme; however, the immobilized Candida rugosa lipase retained over 92 % of the initial activity, even after 3 times reuse. Lipase was also immobilized on the silica-coated magnetite nanoparticles by cross-linked enzyme aggregate (CLEA) using glutaraldehyde and covalent binding, respectively, were also studied. Immobilized Candida rugosa lipase on silica nanoparticles and silica-coated magnetite nanoparticles by CLEA and covalent binding showed higher enzyme activities than free enzyme, while immobilized Candida rugosa lipase retained over 73 % of the initial activity after 5 times reuse.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.2
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• pp.192-197
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• 2017

Objective: The study was conducted to evaluate the stability of commercial coated lipase (CT-LIP) in vitro. Methods: The capsules were tested under different conditions with a range of temperature, pH, dry heat treatment and steaming treatment, simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) in this work, respectively. Free lipase (uncoated lipase, UC-LIP) was the control group. Lipase relative activities measured in various treatments were used as a reference frame to characterize the stability. Results: The lipase activities were decreased with increasing temperatures (p<0.05), and there was a markedly decline (p<0.01) in lipase comparative activities of UC-LIP at $80^{\circ}C$ compared with CT-LIP group. Higher relative activities of lipase were observed in CT-LIP group compared with the free one under acidic ambient (pH 3 to 7) and an alkaline medium (pH 8 to 12). Residual lipase activities of CT-LIP group were increased (p<0.05) by 5.67% and 35.60% in dry heat and hydrothermal treatments, respectively. The lipase relative activity profile of CT-LIP was raised at first and dropped subsequently (p<0.05) compared with constantly reduced tendency of UC-LIP exposed to both SGF and SIF. Conclusion: The results suggest that the CT-LIP possesses relatively higher stability in comparison with the UC-LIP in vitro. The CT-LIP could retain the potential property to provide sustained release of lipase and thus improved its bioavailability in the gastrointestinal tract.

• Journal of Microbiology and Biotechnology
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• v.18 no.4
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• pp.735-741
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• 2008

In our previous study, a surfactant-coated Candida rugosa lipase immobilized in microemulsion-based organogels was exploited for the synthesis of ethyl isovalerate. In the present study, we are focusing on the effective reuse of lipase immobilized in microemulsion-based organogels (MBGs) in terms of retainment of the catalytic activity. As water is one of the co-products in esterification reactions, the removal of water becomes a priority to allow the reaction to work in the forward direction and to prevent back hydrolysis. Taking this fact into consideration, the lipase-containing microemulsion-based organogels were given pretreatment and/or several intermittent treatments with dry reverse micellar solution of AOT in organic solvent during repeated cycles of ester synthesis. The pretreated MBGs with dry reverse micellar solution exhibited lower water content and higher initial rates of esterification in comparison with untreated freshly prepared MBGs. The esterification efficiency of untreated MBGs started decreasing after 5 cycles of reuse and was almost completely lost by the end of the $8^{th}$ cycle. In contrast, pretreated MBGs exhibited a gradual decrease in esterification efficiency after 5 cycles and retained about 80% of the initial activity at the end of the $8^{th}$ cycle. The intermittent treatment of MBGs after every 3 cycles resulted in enhanced reusability of immobilized lipase for up to 9 cycles without significant loss in esterification activity, after which it resulted in a slow decrease in activity with about 27% lower activity at the end of the $12^{th}$ cycle. Furthermore, the treatment conditions such as concentration of AOT in liquid dessicant and time of treatment were optimized with respect to our system. The granulated MBGs proved to be better in terms of initial esterification rates (1.2-fold) as compared with the pelleted MBGs.

• Journal of Microbiology and Biotechnology
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• v.18 no.3
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• pp.465-471
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• 2008

Highly active, stable, and magnetically separable immobilized enzymes were developed using carboxymethyl cellulose (CMC) and diethylaminoethyl cellulose DEAE-C; hereafter designated "DEAE" as supporting materials. Iron oxide nanoparticles penetrated the micropores of the supporting materials, rendering them magnetically separable. Lipase (LP) was immobilized on the surface of the supporting materials by using cross-linked enzyme aggregation (CLEA) by glutaraldehyde. The activity of enzyme aggregates coated on DEAE was approximately 2 times higher than that of enzyme aggregates coated on CMC. This is explained by the fact that enzyme aggregates with amine residues are more efficient than those with carboxyl residues. After a 96-h enantioselective ibuprofen esterification reaction, 6% ibuprofen propyl ester was produced from the racemic mixture of ibuprofen by using DEAE-LP, and 2.8% using CMC-LP.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.7
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• pp.1025-1035
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• 2014

This study assessed the effect of immobilized lipase on weak base styrene resin using polyethyleneimine (PEI) with cross-linking. Two procedures were used in this study. The first one, "mono-layer" lipase immobilization, involves washing PEI after adsorption. The second procedure, "multi-layer" lipase immobilization, has no washing before the cross-linking step. Treverlite XS-100200 (weak base styrene resin) was immersed with PEI solution (2.2 mg/mL). Lipase AH (from Burkholderia cepacia) was adsorbed onto the support coated with PEI before cross-linking with glutaraldehyde. Structured lipid was synthesized by immobilized lipase-catalyzed interesterification using canola oil, palmitic ethyl ester (PEE), and stearic ethyl ester (StEE). Total fatty acid contents of triacylglycerol (TAG) in structured lipids were analyzed to investigate activity, properties, and reusability of immobilized lipases. Activities of immobilized lipases on the multi-layer and mono-layer increased at a high concentration (8 mg/mL) of lipase solution used for immobilization. The results show that immobilized lipase with the mono-layer method at pH 8.0 on resin had the highest total saturated fatty acid content (26.17 area%). Activity of immobilized lipase with the multi-layer method at pH 7.5 on support was lower than that of the mono-layer, but total saturated fatty acid content was 16.79 area% higher than that of lipase AH (15.01 area%).

• Korean Journal of Food Science and Technology
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• v.36 no.3
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• pp.490-500
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• 2004

Brown rice grains were coated by spraying aqueous protein solution extracted from rice bran using 10% ethanol, and dried at room temperature. Coating procedure was repeated 1-5 times to determine effect of repeated coating, Quality changes in coated brown rice grains were observed during 8 weeks storage. Most coated rice grains gave lower peroxide and acid values, which indicate antioxidative effects of coating. Lipase and lipoxygenase activities generally decreased in grains coated more than three times. Microscopic images of whole kernel and longitudinal section revealed cracking on all brown rice grains including control, and hydration rate constants were not significantly different among treated grains. Compared to non-coated brown rice grains, those coated more than three times, after 8 week storage, showed better quality retention observed in (meaning not clear) higher water-binding capacity, lower gel consistency decrease, less browning, and better textural properties in cooked rice, resulting in better sensory quality.

• Journal of Dairy Science and Biotechnology
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• v.15 no.1
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• pp.27-32
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• 1997

Most lipids in milk are dispetsed as the form of fat globules. Apical portion of plasma membrane is coated with fat globules, which are synthesized from mammary epithelial cells and then secreted into the lumen. The unique phenomenon in separation of the plasma membrane from the cell is observed only in mammary system. It has been suggested that milk fat globule membrane(MFGM) is formed from endoplasmic reticulum, Golgi apparatus, secretory granule to plasma membrane. For this reason MFGM is important for nuderstanding the structure and function of biological membrane. Because MFGM also plays an important role in inhibition of lipase action, stimulation of nutrient digestion and absorption, emulsion or function as natural liposome, study of the major components in MFGM will provide the opportunity for more broad industrial uses of MFGM in the future.

• Journal of the Korean Ceramic Society
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• v.59
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• pp.527-535
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• 2020

This study reports the preparation of the Candida antarctica lipase B (CalB) enzyme immobilization on silica-coated magnetic nanoparticles (Si-MNPs@CalB) using various cross-linkers and demonstration of rapid catalytic hydrolysis of p-nitrophenyl alkyl esters. CalB enzymes were coupled with different cross-linker silanes on the Si-MNPs surface. Among these cross-linkers, Cl-functionalized silane was better at immobilization of CalB than the others. Catalytic hydrolysis of p -nitrophenyl alkyl esters was demonstrated against Si-MNPs@CalB as a function of the length of alkyl chain (C₄, C₈, C₁₂, and C₁₆). From the Michaelis-Menten equation and Lineweaver-Burk plots, various enzyme kinetic parameters (i.e., K_m, V_max, and K_cat) were calculated. Catalytic hydrolysis was faster in shorter alkyl chain of p-nitrophenyl alkyl esters with Si-MNPs@CalB in the order C₄>>C₈>C₁₂>>C₁₆. Furthermore, the reusability and optimum catalytic activity of Si-MNPs@ CalB were evaluated as a function of the number of reuses and with different pH values.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.9
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• pp.1184-1189
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• 2010

This work was conducted to examine the variation of immunoglobulins (Igs) in serum, immune milk, normal milk and colostrum upon implantation of a new Antigen Releasing Device (ARD). The core of each ARD housed an immunostimulating complex (ISCOM) that was made of adjuvant Quil A and type XIII lipase from a Pseudomonas sp. Each ARD was coated with polylactic acid, known as polylactide, that controls antigen release. Twenty lactating Chinese Holstein cows were divided into 2 groups (n = 10): test group and control group. All cows in the test group were implanted with a single injection in the right iliac lymph node with 3 types of ARDs, which were designed to release the antigens at d 0, 14 and 28 post-implantation. Blood and milk samples were collected from both groups, and colostrum samples were also collected from other post-partum cows in the same farm. Concentrations of $IgG_1$, IgA and IgM in whey and serum were measured by sandwich ELISA. The results showed that the $IgG_1$, IgA and IgM concentrations in serum and whey from the test group were higher than from the control group. Among the three Igs measured, the $IgG_1$ concentration in serum was significantly higher at d 40 after ARD implantation, and the $IgG_1$ concentration in whey peaked at d 9, 17 and 30, which corresponded with release of the antigen. Based on Pearson's correlation between Ig concentration and production parameters, IgA concentration in normal milk was positively correlated with lactation period, which reflected IgA changes during the lactation period in immune milk. In colostrum, $IgG_1$, IgA and IgM decreased abruptly from d 0 to 3, and then decreased slightly. In conclusion, serum $IgG_1$ concentration can be affected by controlled release of the ARD, while whey IgA levels are primarily affected by lactation period. These results may be useful in future studies designed to regulate concentrations of Igs in immune milk.