PROCESS BIOCHEMISTRY
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2020
·
IF 2.952
Jianfeng Mei,Xiaoyun Zhao,Yu Yi,Yanlu Zhang,Xudong Wang,Guoqing Ying
Natural astaxanthin is widely used as a food and cosmetics additive because of its multiple biological activities. However, astaxanthin produced by Haematococcus pluvialis is generally esterified, and its activity is far less than that of free astaxanthin. Hydrolysis of astaxanthin esters to free astaxanthin by enzymes can overcome the drawbacks of chemical saponification methods. In this paper, a slug-flow microchannel reactor was constructed and tested in enzymatic hydrolysis of astaxanthin esters. The reactor consists of a “T” slug-flow generator, a stainless-steel microchannel, two constant-flow pumps, and a temperature controller. The reactor has the advantages of simple configuration and easy scale-up, and is suitable for two-phase biochemical reactions. Using the microchannel reactor, astaxanthin esters in H. pluvialis oil were efficiently hydrolyzed to free astaxanthin by lipase from Aspergillus niger . After hydrolysis, the content of free astaxanthin in H. pluvialis oil was 18.8 mg/L, 7.83-times higher than that before hydrolysis (2.13 mg/L). The hydrolysis rate reached 75.4 %. These results indicate that the microchannel reactor can be useful for the production of free astaxanthin from its esters.
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高影响因子
STARCH-STARKE
·
2021
·
IF 2.741
Hui Yang,Rihui Lin,Yanye Fan,Sai Jiang,Yujiao Lin
The rosin acid starch (RAS) is prepared under the catalysis of lipase, by esterification on the starch particles' surface in a two-phase reaction system, using rosin acid and native cassava starch as starting materials. The effects of reaction time, solvent types, substrate ratio, reaction temperature, and lipase dosage on the degree of substitution (DS) of RAS are investigated. Based on the single factor experiments, the reaction conditions are optimized according to the principle of the combination Box-behnken centered design and response surface methodology analysis. The mathematical model of the influence of reaction temperature, material ratio, and enzyme addition amount on DS is established. The optimum synthesis conditions are determined as follows: solvent, trichloromethane; reaction time, 10 h; reaction temperature, 59 °C; substrate ratio (m Rosin acid :m starch) , 4.1; and lipase dosage, 264 µL. Under these conditions, it is found that the DS is 0.0608. The analysis of variance and verification experiments show that the mathematical model has good fit degree and high credibility. Compared with the native cassava starch, RAS has improved contact angle, emulsion capacity, and emulsion stability.
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ACS Sustainable Chemistry & Engineering
·
2020
·
IF 7.632
Xiaohui Di,Yu Zhang,Junying Fu,Qiang Yu,Zhongming Wang,Zhenhong Yuan
Dimethyl itaconate (DI), a promising biomass-derived intermediate, cannot be synthesized from itaconic acid (IA) in organisms due to the lack of metabolic pathways. It is necessary to develop a green and high-efficiency method to synthesis DI from IA. In this study, DI was, for the first time, produced from IA in an aqueous medium by an ionic liquid-strengthened enzymatic method. We found that when pretreated by the ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]), the pH tolerance range of the lipase shrunk and the hydrolysis activity of it was greatly inhibited, while its esterification activity was not. Moreover, when the [bmim][PF6]-treated immobilized Rhizomucor miehei lipase (RML, 50 mg/mL) was employed in a reaction containing IA/methanol at a molar ratio of 1:30 and methanol/water in a volume ratio of 1:10 at 30 °C after 24 h, a 64.3% yield and 73.2% selectivity of DI was obtained. The results of HPLC and GC–MS revealed that in addition to the main product DI, other side products including acetic acid, propionic acid, and itaconic acid cyclolactone were also generated, which indicates that the RML-catalyzed esterification of IA and methanol has various side reactions, such as lactonization and self-decomposition of IA.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2019
·
IF 3.571
Xiumei Wang,Xiaoli Qin,Xiuting Li,Zexin Zhao,Bo Yang,Yonghua Wang
n-3 polyunsaturated fatty acid (PUFA)-rich lysophosphatidylcholine (LPC) with many beneficial effects was effectively synthesized by immobilized MAS1 lipase-catalyzed esterification of n-3 PUFA with sn-glycero-3-phosphatidylcholine (GPC) under vacuum in a solvent-free system. Immobilized MAS1 lipase was found to be a more suitable catalyst for the production of n-3 PUFA-rich LPC when compared with Novozym 435. The maximal GPC conversion and LPC content (93.12% and 90.77 mol %) were obtained under the optimized conditions (enzyme loading of 300 U/g substrate, temperature of 55 °C, and n-3 PUFA/GPC molar ratio of 20:1). Moreover, it was observed that 1-acyl-sn-glycero-3-lysophosphatidylcholine (sn-1 acyl LPC) was the main reaction product, as demonstrated by molecular docking. These results showed that immobilized MAS1 lipase had high phospholipase activity with a predominant specificity for the sn-1 hydroxyl position of GPC to efficiently synthesize highly pure n-3 PUFA-rich LPC from GPC for industrial application.
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PubMed
高影响因子
FOOD CHEMISTRY
·
2018
·
IF 4.946
Yongsheng Chen,Jiangwei Liu,Sheng Geng,Yonglan Liu,Hanjun Ma,Jie Zheng,Benguo Liu,Guizhao Liang
Herein, we perform the regioselective acetylation of phloridzin catalyzed by immobilized Candida antarctica lipase B (CALB). We show that the enzyme amount and reaction time can significantly influence the composition of mono-, di- and tri-acetylated phloridzin in the product. The last acetylated derivative of phloridzin is isolated and identified as 4, 3″, 6″-3-O-acetyl-phloridzin by HPLC, UV, IR, MS and NMR. Molecular docking suggests that the first acetylation of phloridzin catalyzed by CALB occurs in 6″-OH, followed by 3″-OH, then 4-OH. During this process, hydrogen bond and hydrophobic forces play an important role in maintaining the binding interaction of CALB with phloridzin or its acetylated derivatives. Although, tri-acetylated phloridzin has moderate to minimal adverse-effects on LO-2, its anti-proliferative activity against human HepG2 cancer cells is superior to that of phloridzin, which attributes to its high capacity of inducing cell apoptosis, retarding cell cycle, lowering mitochondrial membrane potential and scavenging intracellular ROS.
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PubMed
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2015
·
IF 2.587
Xiujuan Li,Chuan Zhang,Shuang Li,He Huang,Yi Hu
Candida rugosa lipase was chemically modified with various polyethylene glycol functional ionic liquids to increase its catalytic performance. All tested polyethylene glycol functional ionic liquids improved lipase catalytic activity, thermostability, organic solvent tolerance, and adaptability to temperature and pH changes in olive oil hydrolysis reaction. In particular, lipase modified by [HOOCEPEG350Im][H2PO4] increased the catalytic activity by 1.7-fold, thermostability by 5.0-fold at 50 °C for 2.5 h, organic solvent tolerance by 13.3-fold in 60% dimethyl sulfoxide and 3.4-fold in 5% methanol compared with the native lipase. Investigations by ultraviolet, fluorescence, and circular dichroism spectroscopy revealed microenvironment changes, the increase in β-sheet and the decrease in α-helix content of secondary structures in the modified lipases. These changes were correlated with enzymatic properties alteration, including improved activity and stability of modified lipases. Compared with the results of previous reports, the novel modification with polyethylene glycol functional ionic liquids was more effective in improving the catalytic performance of lipase.
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RSC Advances
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2015
·Vol. 5
·期 126
·103943-103955
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IF 3.84
Yongbo Shao,Tao Jing,Jingzhi Tian,Yongjie Zheng
Nano- and hybrid materials have recently emerged as a new approach for improving enzyme activity and stability, and are suitable for commercial applications. In this paper, graphene oxide-based magnetic hybrids were prepared successfully. A chloropropyl-functionalized graphene oxide decorated with Fe3O4 nanoparticles was made, denoted as CPS/GO-Fe3O4@MCM-41. This was characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, vibrating sample magnetometry, thermogravimetry and N2 adsorption/desorption. Then, porcine pancreas lipase (PPL) was immobilized onto the graphene oxide-based magnetic nanoparticles via covalent bonding. The results show that the novel supporting material CPS/GO-Fe3O4@MCM-41 was the best for PPL immobilization compared to two other nanomaterials (GO-Fe3O4@MCM-41 and GO-Fe3O4). The supporting material CPS/GO-Fe3O4@MCM-41 exhibited enhanced immobilization efficiency (up to 98%), maximum relative activity (up to 97.9%), high stability and reusability (85% after 56 d and 87% after 10 cycles respectively, both at 30 °C). Additionally, it offered some other advantages, such as easy recycling and reuse, complying with the requirements of green chemistry. Therefore, it is proposed that CPS/GO-Fe3O4@MCM-41 provides a new approach for commercial applications.
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JOURNAL OF MOLECULAR CATALYSIS B-ENZYMATIC
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2015
·
IF 2.128
Wei-Wei Zhang,Xian-Ling Yang,Jun-Qi Jia,Na Wang,Cheng-Li Hu,Xiao-Qi Yu
Novel surfactant-activated magnetic cross-linked enzyme aggregates of Thermomyces lanuginosus lipase (TLL-magnetic-CLEAs) were developed and provided an efficient approach to improve the activity and stability of lipase for biodiesel production. In the methanolysis of Jatropha oil for biodiesel synthesis, the maximum yield in isopropyl ether was 88% after 48 h at 40 °C, representing 3.5-fold and 2.5-fold higher activity than that exhibited by free TLL and TLL CLEAs, respectively. Moreover, Tween 80-activated TLL-magnetic-CLEAs retained their activity during storage at 4 °C for 11 weeks and 10 cycles of repeated 48 h biodiesel reactions at 40 °C (over 30 days). Additionally, the surface morphology, particle size and loading of lipase aggregates were confirmed by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The combination of interfacial activation, high specific enzyme activity, improved stability and easy recovery of magnetic CLEAs presents an attractive process for lipase immobilization and provides a promising catalyst for biodiesel production.
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CHINESE JOURNAL OF CATALYSIS
·
2013
·
IF 1.304
Yi Hu,Xiangjun Jiang,Suwen Wu,Ling Jiang,He Huang
Vitamin E succinate was synthesized by interfacial activated Candida rugosa lipase (CRL) encapsulated in sol-gel materials. The effects of various immobilization parameters were investigated. The optimum conditions were found to consist of n -propyltrimethoxysilane/tetraethoxysilane molar ratio = 1/1, water/silane molar ratio ( R value) = 20, lipase loading = 0.5 mg/ml sol, and PEG400 loading = 12 μl/ml sol. Compared with free enzymes, sol-gel encapsulated enzymes kept its activity of 70.58% and achieved 2.6-fold increased stability after 18 h incubation in phosphate buffer (0.025 mol/L, pH = 7.0) at 50 °C. Based on the interfacial characteristics of CRL, five kinds of surfactants were used for activation. The results demonstrate that olive oil was the most effective in activating CRL. The esterification activity of vitamin E succinate synthesis by interfacial activated CRL encapsulated in sol-gel materials reached up to 6.7-fold and 1.43-fold that of free enzyme and non-interfacial activated enzyme, respectively.
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BIOPROCESS AND BIOSYSTEMS ENGINEERING
·
2015
·Vol. 38
·期 5
·939-946
·
IF 1.997
Zeng Chaoxi,Qi Suijian,Li Zhigang,Luo Riming,Yang Bo,Wang Yonghua
A water-in-ionic liquid microemulsion ([Bmim]PF 6 /Tween20/H 2 O) was applied as reusable reaction medium to esterify phytosterols with fatty acid by Candida rugosa lipase (CRL) successfully. Two kinds of commercial CRLs, AY30 and AYS which cannot effectively catalyze esterification in conventional reaction system were found effective in the microemulsion system. Effects of reaction parameters on esterification were investigated; results showed that the conversion rate of 87.9 and 95.1 % was obtained in 24 and 48 h of reaction, respectively, under the optimized condition: the molar ratio of water to Tween 20 ( w
0 value) at 5.4, Tween 20 at a concentration of 305 mM, 50 °C,pH 7.4, 10 % of enzyme loading (w/w, with respect to total reactants), and phytosterols/lauric acid molar ratio of 1:2. Moreover, by using n-hexane as the extraction agent, the lipase-encapsulated microemulsion could be reused at least seven times (>168 h) without significant changes in the conversion rate, while achieving a purpose of simple separation and purification.
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PubMed
高影响因子
JOURNAL OF MOLECULAR CATALYSIS B-ENZYMATIC
·
2015
·
IF 2.128
Chuan-Yang Shang,Wei-Xun Li,Feng Jiang,Rui-Feng Zhang
ZnO nanowires/macroporous SiO 2 composites were used as a new type of microwave absorbing support to immobilize Candida rugosa lipase (CRL). Under microwave irradiation the immobilized lipase was used to catalyze esterification of phytosterol and oleic acid for the synthesis of phytosterol esters. A great improvement of the catalytic activity was found in the systems in which composited ZnO nanowires were present. The microwave absorbing properties of ZnO nanowires have been proved to be helpful for the synergistic effect between microwave irradiation and enzyme catalysis. The immobilized CRL showed higher thermal stability at 55 °C under microwave irradiation than conventional heating. A maximum molar conversion of 95.4% under microwave irradiation was achieved under the optimal condition: 0.1 M phytosterol, 0.2 M oleic acid, water activity ( a w ) of 0.11, reaction temperature at 50 °C and reaction time of 1 h.
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CLINICAL NUTRITION
·
2014
·
IF 3.94
Lulu Xia,Chaonan Fan,Hua Dong,Cui Wang,Yuanyuan Lu,Richard J. Deckelbaum,Kemin Qi
Summary Background & aims The catabolic pathways of n-3 triglyceride (TG) rich particles (n-3 TGRP) have not been clearly elucidated. In this study, we investigated the effects of lipoprotein lipase (LPL) on the catabolism of n-3 TGRP compared to n-6 TGRP in vivo and in vitro, and we determined whether particle size affects the biological functions of LPL in n-3 TGRP catabolism. Methods Four types of lipid emulsions , chylomicron (CM)-sized n-3 TG and n-6 TG emulsions, and very low density lipoprotein (VLDL)-sized n-3 TG and n-6 TG emulsions, were labeled with 1,1′-dioctadecy1-3,3,3′,3′-tetramethylindo-carbocyanine perchlorate (DiI) and administered via a bolus injection to LPL gene knockout (LPL+/−) mice in vivo and were added to cultured LPL miRNA-transfected 3T3-L1 adipocytes in vitro. Results With CM-sized emulsions, a reduction in LPL expression in LPL+/− mice had almost no effect on tissue uptake of n-3 TG emulsions with smaller changes in their initial blood clearance ; however, greater effects were observed for VLDL-sized n-3 TG emulsions with respect to tissue uptake with greater changes in their initial blood clearance, compared to n-6 TG emulsions with the same size. In vitro, LPL miRNA transfection had smaller effects on CM-sized and greater effects on VLDL-sized n-3 TG emulsions, with respect to particle uptake, cell TG mass, particle-cell binding and particle lipolysis . Conclusion These results suggested that LPL is more important for catabolism of n-3 TGRP of smaller size; whereas it is essential for catabolism of all sizes of n-6 TGRP.
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高影响因子
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