BIOPROCESS AND BIOSYSTEMS ENGINEERING
·
2021
·Vol. 45
·期 1
·147-158
·
IF 3.21
Jiaojiao Xia,Yan Yan,Bin Zou,Feng Liu
The cross-linked enzyme aggregates (CLEAs) are one of the technologies that quickly immobilize the enzyme without a carrier. In this study, ionic liquid with amino group (1-aminopropyl-3-methylimidazole bromide, FIL) was used as the novel functional surface molecule to modify CRL ( Candida rugosa lipase, CRL). The enzymatic properties of CRL-FIL-CLEAs were investigated. The activity of CRL-FIL-CLEAs (5.51 U/mg protein) was 1.9 times higher than that of CRL-CLEAs (2.86 U/mg protein) without surface modification. After incubating in a centrifuge tube for 50 min at 60 °C, CRL-FIL-CLEAs still maintained 61% of its initial activity, while the value for CRL-CLEAs was only 22%. After repeated use for five times, compared with the 22% residual activity of CRL-CLEAs, the value of CRL-FIL-CLEAs was 51%. Based on the above results, it was indicated that this method provided a new idea for the effective synthesis of immobilized enzyme.
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高影响因子
CLAYS AND CLAY MINERALS
·
2021
·Vol. 69
·期 4
·434-442
·
IF 1.609
Zhang Mingzhu,Sun Shiyong,Lv Rui,Golubev Yevgeny Aleksandrovich,Wang Ke,Dong Faqin,Kotova Olga Borisovna,Kotova Elena Leonidovna
Lipase is an industrial enzyme, the catalytic efficiency of which is restricted by various environmental factors. To improve this efficiency, immobilization technology has been utilized in the past to improve the stability of lipase in harsh conditions. Immobilization technology can be divided into physical methods and chemical methods. Some unsolved problems remain in current immobilization technology. The interaction between enzyme and immobilization support is weak and reversible during physical adsorption, resulting in poor stability of the immobilized enzyme and the contamination of substrate solution by leached enzymes. In chemical methods, enzyme-active sites might be inactivated due to the chemical reactions between enzyme molecules and support, resulting in a decrease in the enzymes’ catalytic activity (Liu et al., 2018a ). The objective of the current study was to construct a nanostructured lipase via Mg-amino-clay as a carrier and improve the catalytic activity and stability of lipase by immobilization. Lipase produced by Aspergillus oryzae was immobilized on aminopropyl functionalized magnesium phyllosilicate (a 2:1 trioctahedral talc-like silicate Mg-amino-clay) via a 1-(3-Dimethylaminopropyl)-3-ethyl-carbodiimide hydrochloride (EDC) coupling agent. The physical and chemical properties of the Mg-amino-clay and Mg-amino-clay-based nanostructured biocatalyst (Mg-clay-lipase) were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, and scanning electron microscopy. Optimal immobilization conditions were determined by taking into account the following variables: amount of initial lipase, EDC concentration, and reaction time. The results revealed that the optimum temperature, pH, and thermal stability of Mg-clay-lipase were greater than equivalent values for free lipase under optimal conditions (described below – Process for Immobilization of Lipase on Mg-amino-clay ). The Michaelis-Menten constant (K m ) values were 5.25 mM and 7.42 mM while the maximum reaction rates ( v max ) were 30.58 mM/(L·min) and 55.87 mM/(L·min) for free lipase and Mg-clay-lipase, respectively. The present study provided a new nanostructured biocatalyst and demonstrated that the enzyme activity and stability of Mg-clay-lipase were superior to those of free lipase due to the mechanism of 'interface activation'.
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Molecular Catalysis
·
2021
·
IF 5.062
Wei Su,Qingyun Li,Youyan Liu,Yimin Qin,Haibo Liu,Aixing Tang
Taking advantage of the intersolubility of alcohol and water, we developed an efficient single-phase system for chemoenzymatic epoxidation of (-)-α-pinene. Different from traditional methods, it included all substrates, such as (-)-α-pinene, acyl donors and oxidants, into one phase. Isopropanol was eventually selected as the epoxidation medium to optimize three controllable parameters. Under the optimal conditions of 3.35 mol/L ethyl acetate and 1.1 mol/L H 2 O 2 , the conversion and selectivity reached 92.3% and 86.6% in 90 min, respectively, and the initial reaction rate was 13.58×10 −4 mmol·min −1 ·mg −1 with Novozym435 as a catalyst. Trisodium citrate was screened as an acid-trapping reagent to eliminate the negative impact of acetic acid on (-)-α-pinene oxide. The enzyme reusability was at least 6 cycles with a relative activity of 57.5% at the sixth cycle.
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Catalysts
·
2020
·Vol. 10
·期 11
·1266
·
IF 3.52
Ting Zou,You-dan Duan,Qiao-e Wang,Hai-ming Cheng
Biodiesel offers an important alternative to fossil fuel. In this work,Eversa Transform2.0 lipase was immobilized onto 3-aminopropyltriethoxysilane (APTES) modified silica clay (SC) by glutaraldehyde. The characteristics of the functionalized supports and the immobilized lipase were investigated by FTIR, TEM, BET, and XRD. The results show that the optimal conditions of lipase immobilization are as follows: 2% glutaraldehyde concentration, 15 mg/mL lipase concentration and incubating at 25 °C for 60 min. The immobilized lipase showed a high tolerance to temperature and pH variation in comparison to the free lipase. The immobilized lipase on SC was applied as a biocatalyst for the synthesis of biodiesel from methanol and canola oil. A biodiesel yield of 86% was obtained at a temperature of 45 °C via a three-step methanol addition. A conversion yield of 67% was maintained after reusing the immobilized lipase for five cycles. This work provides a strategy for the preparation of an efficient biocatalyst for the synthesis of biodiesel.Keywords:lipase;silica clay;biodiesel;immobilization;APTES;glutaraldehyde
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JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
·
2020
·Vol. 95
·期 5
·1421-1430
·
IF 2.75
Yuanyuan Zhang,Yangjian Sun,Wenjie Ren,Qiuxiang Zhao,Kuiying Lv,Hui Tang,Xin Gao,Fengke Yang,Fanye Wang,Junhong Liu
BACKGROUND Mitomycin C (MMC) is one of the most important members of the mitomycin family that have been widely used as a strong antineoplastic antibiotic for treating various tumors. In this study, enzymatic oxidation/amination reaction of 2-methyl-1,4-hydroquinone with n -butylamine was carried out to synthesize 2-methyl-3- n -butylaminoyl-1,4-benzoquinone mitomycin analogs. RESULTS A kinetic model was developed based on an ordered sequential mechanism for this cascade reaction system catalyzed by two enzymes, which revealed that the limiting step of the system was the laccase-mediated oxidation of 2-methyl-3- n -butylaminoyl-4-hydro-1-quinone and removing the limiting step resulted in a yield increase from 88.3% to 96.7%. CONCLUSION The developed kinetic model fitted the test data very well, indicating that the reactions catalyzed by coupling of laccase with lipase might follow the ordered sequential mechanism with product inhibition. Synthesis of mitomycin analogs catalyzed by coupling of laccase with lipase has great potential for practical application. © 2020 Society of Chemical Industry
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Journal of Oleo Science
·
2020
·
IF 1.304
Zhihao Wang,Ying Chen,Jiahe Zhao,Guoliang Gao,Worawan Panpipat,Ling-Zhi Cheong,Cai Shen
Present study has successfully synthesized melamine-based covalent organic polymers (MCOPs) and applied it as lipase carrier for recyclable esters hydrolysis and transesterification. The synthesized MCOPs are composed of dense nanosheet structures having a thickness of 3.5 nm. Three immobilization methods namely physical adsorption, cross-linking and carrier activation were employed to prepare the MCOPs-immobilized CRL. Cross-linked MCOPs-immobilized CRL (41.30 mg protein/g MCOPs) and carrier activated MCOPs-immobilized CRL (33.20 mg protein/g MCOPs) had higher enzyme loading as compared to physical absorb MCOPs-immobilized CRL (29.30 mg protein/g MCOPs). Nevertheless, physical absorb MCOPs-immobilized CRL demonstrated the highest esters hydrolysis (49.85 U) and transesterification (1.04 U) activities. Despite having the highest enzymatic activity, physical absorb MCOPs-immobilized CRL were not able to maintain its catalytic stability with more than 30% decreased in enzymatic activity during consecutive hydrolysis and transesterification activities. Meanwhile, cross-linked MCOPs-immobilized CRL demonstrated highest catalytic stability with highest enzymatic activities at the end of consecutive reactions. All the MCOPs-immobilized CRL can be easily recovered and reused through centrifugation with more than 85% of recovery rate.
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2023
·
IF 4.4
Shiyi Chen,Mengli Ma,Juan Peng,Xiaogang He,Qian Wang,Ganghui Chu
Candida rugosa lipase (CRL, EC3.1.1.3) is one of the main enzymes synthesizing esters, and ZIF-8 was chosen as an immobilization carrier for lipase. Enzyme activity testing often requires expensive reagents as substrates, and the experiment processes are time-consuming and inconvenient. As a result, a novel approach based on near-infrared spectroscopy (NIRs) was developed for predicting CRL/ZIF-8 enzyme activity. The absorbance of the immobilized enzyme catalytic system was evaluated using UV–Vis spectroscopy to investigate the amount of CRL/ZIF-8 enzyme activity. The powdered samples' near-infrared spectra were obtained. The sample’s enzyme activity data were linked with each sample’s original NIR spectra to establish the NIR model. A partial least squares (PLS) model of immobilized enzyme activity was developed by coupling spectral preprocessing with a variable screening technique. The experiments were completed within 48 h to eliminate inaccuracies between the reduction in enzyme activity with increasing laying-aside time throughout the test and the NIRs modeling. The root-mean-square error of cross-validation (RMSECV), the correlation coefficient of validation set (R) value, and the ratio of prediction to deviation (RPD) value were employed as assessment model indicators. The near-infrared spectrum model was developed by merging the best 2nd derivative spectral preprocessing with the Competitive Adaptive Reweighted Sampling (CARS) variable screening method. This model's root-mean-square error of cross-validation (RMSECV) was 0.368 U/g, the correlation coefficient of calibration set (R_cv) value was 0.943, the root-mean-square error of prediction (RMSEP) set was 0.414 U/g, the correlation coefficient of validation set (R) value was 0.952, and the ratio of prediction to deviation (RPD) was 3.0. The model demonstrates that the fitting relationship between the predicted and the reference enzyme activity value of the NIRs is satisfactory. The findings revealed a strong relationship between NIRs and CRL/ZIF-8 enzyme activity. As a result, the established model could be implemented to quantify the enzyme activity of CRL/ZIF-8 quickly by including more variations of natural samples. The prediction method is simple, rapid, and adaptable to be the theoretical and practical basis for further studying other interdisciplinary research work in enzymology and spectroscopy.
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LWT-FOOD SCIENCE AND TECHNOLOGY
·
2023
·
IF 6
Haocheng Liu,Yuqian Tang,Shangwei Zhang,Xiaofei Xu,Jiguo Yang
The present study investigated the physicochemical properties of the newly synthesized polyglycerol fatty acid esters (PGFEs) and their potential application as food emulsifiers. It turned out that the complete removal of glycerol from crude polyglycerol was achieved by optimizing the molecular distillation temperature (120 °C). Moreover, novozym 435 was used to catalyze the synthesis of PGFEs with different aliphatic chain lengths, and the esterification rate of the obtained products was 93%∼98%. The characteristic absorption peak of the ester carbonyl group was displayed at 1738 cm −1 , and that of C–O–C on the ether bond was at 1100 cm −1 and 1048 cm −1 . Therefore, the synthesis can be determined to be PGFEs. Their hydrophilic lipophilic balance (HLB) values are >7, which can be used as oil-in-water emulsifiers. When curcumin nanoemulsions were constructed by PGFEs with various aliphatic chains as emulsifiers, it was found that all PGFEs in C10∼C18 can form stable curcumin nanoemulsions (encapsulation rate was >95%). PGFEs with longer aliphatic chains can stabilize nanoemulsions more efficiently (larger droplet sizes and lower ζ-electric potential), and showed better storage and UV stability. Whereas, medium-chain PGFEs emulsions, especially PGC, showed the best curcumin release efficiency, which theoretically supported the application of PGFEs to functional emulsion products.
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FOOD CHEMISTRY
·
2023
·
IF 8.8
Danyu Lv,Muyun Wang,Wanjun He,Jieli Wu,Xiaoyue Liu,Yongguang Guan
Bixin has desirable bioactivities but poor water solubility, which limits its practical applications. Enzymatic transesterification of methyl to alditol groups in bixin by Candida antarctica lipase B (CALB) improves bixin water solubility. Herein, magnetic CALB nanoreactors with diameter of 11.7 nm and CALB layer thickness of 3.5 nm were developed by covalently linking CALB onto silicon covered Fe 3 O 4 nanoparticles. The CALB loading capacity in nanoreactors achieved 30%. The Michaelis constant ( Km ) and maximum reaction rate of magnetic CALB nanoreactors were 56.1 mmol/L and 0.2 mmol/(L·min). Magnetic CALB nanoreactors could circularly catalyze bixin-maltitol ester synthesis and keep catalytic efficiency of 62.6% after eight repetitive enzymatic reactions. Additionally, the optimal bixin-maltitol ester synthesis procedure was heating bixin-maltitol mixture at molar ratio of 1:7 in anhydrous 2-methyl-2-butanol-dimethylsulfoxide (8:2, v/v) at 50 °C for 24 h. Bixin-maltitol ester showed improved water solubility at pH 5.5 and 7.0.
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CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Zhaoxin Wang,Jinlan Wen,Jihang Zhang,Jiawei Deng,Wei Zhuang,Jinle Liu,Zhi Wang,Yuan Rao,Yudan Zhu,Hanjie Ying
Lipase catalysis plays an important role in bioengineering and food science and is widely used in the organic solvent environment. The addition of trace water to organic media can significantly change lipase activity, and the reason is essential to understand. In this study, by combining experiments and molecular dynamics simulations, we studied solvent-free acidolysis of the tripalmitin (PPP) with different water contents and revealed the mechanism of the water effect on lipase activity from atomic insight. Enzyme activity experimentally exhibited an increasing but subsequently decreasing trend with the rise of water content. Through molecular dynamics (MD) simulations, we found that the reaction activity was affected by three aspects: lipase flexibility, substrate diffusion and substrate spatial distribution. Lipase flexibility, as the structural basis of catalytic activity, increased with water content. At lower water content, the diffusion ability of the substrate around the lipase was dominant. With water content increasing, water molecules on the protein surface gradually shielded hydrogen bonds (HBs) between the oleic acids (OA) and the lipase, which improved the diffusion ability of the substrate near the enzyme surface and thus beneficial to the reaction occurring. At higher water content, the spatial distribution dominated the reaction, where the thicker water layer on the lipase surface acted as a spatial barrier hindering the access of substrate OA to the enzyme and thus harmful to the reaction. Our work helps to provide guidance on controlling enzyme activities in organic solvent systems.
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CLAY MINERALS
·
2019
·Vol. 54
·期 3
·293-298
·
IF 1.787
Dong Li,Min Shen,Guofan Sun,Huiran Jin,Peng Cai,Zhihui Wang,Yeling Jin,Jing Chen,Shijie Ding
A Pickering emulsion was prepared via synergistic stabilization of a lipase and palygorskite particles. The optimum conditions for the stabilization of the Pickering emulsion, such as the concentrations of the palygorskite particles and lipase, were explored. The morphology of emulsion droplets was examined using digital optical microscopy and polarizing optical microscopy. The palygorskite–lipase co-stabilized Pickering emulsions were investigated by determination of the adsorption rate, pH and zeta potential of the aqueous dispersion, as well as by determining the contact angle values of the lipase solution on a palygorskite disc that was immersed in toluene. The catalytic performance of the immobilized lipase in the Pickering emulsion was studied via the investigation of its thermal stability, storage stability and reusability. The immobilized lipase showed greater stability than the free lipase. The lipase immobilized by Pickering emulsion retained a high level of activity even after seven periods of recycling.
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BIOPROCESS AND BIOSYSTEMS ENGINEERING
·
2018
·Vol. 41
·期 5
·739-748
·
IF 2.139
Jiaojiao Xia,Bin Zou,Gangbin Zhu,Ping Wei,Zhenjiang Liu
To promote the activity and stability of immobilized porcine pancreatic lipase (PPL), novel carrier was combined with special immobilization method. Enzymatic activity was enhanced after immobilized onto ionic liquid modified magnetic Fe 3 O 4 by electrostatic adsorption. Activity of immobilized enzyme (PPL-IM/BF 4 -Fe 3 O 4 @CA) reached 596 U/g PPL. Through the combination of electrostatic adsorption and embedding immobilization methods, we improve binding force between the carrier and enzyme, and further enhance the efficiency and stability of immobilized enzyme. The activity of PPL-IM/BF 4 -Fe 3 O 4 @CA after repeated third use was 78%. After storage at room temperature for 5 days, the residual activity was 89%. Enzymatic properties and catalytic kinetics of immobilized enzymes were studied, and the effect mechanism of ionic liquid modified Fe 3 O 4 on PPL was revealed. The effect of ionic liquid on the carrier structure was investigated by characterization of XRD, FT-IR, SEM and TG. The mechanism and enzymatic properties of immobilized PPL via electrostatic adsorption and embedding were analyzed. A novel and efficient immobilized PPL was developed.
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