ENZYME AND MICROBIAL TECHNOLOGY
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2022
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IF 3.705
Liya Zhou,Yaping Ouyang,Weixi Kong,Teng Ma,Hao Zhao,Yanjun Jiang,Jing Gao,Li Ma
In this study, a novel kind of Ni-NTA modified monodispersed SiO 2 nanoflowers (Ni-NTA@SiO 2 nanoflowers) were successfully synthesized. The obtained Ni-NTA@SiO 2 nanoflowers were used to specifically adsorb and purify His-tagged old yellow enzyme (OYE1) and glucose dehydrogenase (GDH), which allows access to optically pure (3 S)− 3-methyl-cyclohexanone through asymmetric hydrogenation reaction, and forms a cofactor regeneration system. The protein loading amount on Ni-NTA@SiO 2 nanoflowers was 40.17 mg/g support and the activity recoveries of OYE1 and GDH were 81.53% and 79.68%, respectively. The effects of pH and temperature on the activity of free and co-immobilized enzymes were investigated, and the stability as well as reusability were also measured. Compared to free enzymes, the co-immobilized enzymes showed higher thermal and storage stability. The co-immobilized enzymes were applied to asymmetric reduction of C C bonds for the synthesis of a chiral center with excellent enantioselectivity (ee > 99%), and the conversion was 46.02% after 7 cycles. This work introduced a one-pot multi-enzyme purification and co-immobilization strategy to construct efficient cofactor regeneration system with high activity and stability.
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BIOCHEMICAL ENGINEERING JOURNAL
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2022
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IF 4.446
Jiacong Wu,Yi Wang,Juan Han,Lei Wang,Chunmei Li,Yanli Mao,Yun Wang
In this work, a mesoporous Zr-based MOF (MP-UIO-66) was first synthesized by biomineralization method using dextran as template and the resultant particles were applied in the immobilization of cellulase . Compared with conventional UIO-66, MP-UIO-66 has more mesoporous channels (4.6 nm) that allow cellulase (3.4 * 12.4 nm) to be entrapped into the channels, improving loading capacity and stability of immobilized enzyme . Specifically, the results showed that MP-UIO-66 had an excellent loading capacity (265 mg g −1 ) for cellulase, and the residual enzyme activity of PVP-cellulase@MP-UIO-66 (PCMU) was still about 83% after 6 cycles. Moreover, the suitable pore structure exposes the active center of cellulase to the external environment, which facilitates the mass transfer of the substrate. Based on Michaelis-Menten constant analysis, the substrate affinity (13.355 mg mL −1 ) and catalytic efficiency (1.311 mL mg −1 min −1 ) of PCMU were better than those of free cellulase (14.525 mg mL −1 , 0.732 mL mg −1 min −1 ).
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CHEMICAL ENGINEERING JOURNAL
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2022
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IF 16.744
Chen Wang,Mingjie Huang,Wei Lou,Wei Xiang,Tao Zhou,Juan Mao,Feixiang Zan,Xiaohui Wu
In-situ removal of Cr(VI) by metallic (oxides) materials is generally limited by rapid loss of surface active sites, especially in neutral water/wastewater circumstances co-existing organic ligands impurity. This study has firstly demonstrated that synthesized magnetic electron-rich copper-iron oxides composites (Cu 2 O-Fe 3 O 4 ) could successfully achieve amazingly efficient reductive immobilization of Cr(VI) induced by common citric ligand (Cit). As Cr(VI) reduced heterogeneously on the composites, immobilization of the generated Cr(III) was almost synchronous via a “spatially-separated” way and correlated linearly with simultaneous dissolved Cu. DFT calculations indicated more appropriate adsorption energy of Cit in realizing its preferential coordination on Fe 3 O 4component surface and Cr(VI) adsorption on Cu 2 O component , as compared to oxalic, tartaric and EDTA ligands. The complexed Cit (Cit≡Fe 3 O 4component ) would promote internal electron transfer from Fe 3 O 4component to Cu 2 O component then adsorbed Cr(VI), causing a highly improved electron efficiency of 72.25%. Most importantly, acting as a regulator of the continuously synchronous reduction and immobilization, Cit≡Fe 3 O 4component would tendentiously chelate newborn Cu(II) at Cu 2 O component surface to release bulk Cu 2+ -Cit complexes, refreshing the reduction sites as well as favoring the Cr(III) immobilization of great stability at the exposed sites of Fe 3 O 4component . This study has revealed that specific impurity ligands can stimulate and tune effective reductive immobilization of heavy metal oxyanions by electron-rich materials under near-neutral conditions, providing a new method towards the efficient treatment of Cr(VI) contaminated wastewaters.
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Frontiers in Bioengineering and Biotechnology
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2022
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IF 6.064
Ni Yun,Lv Zhixiang,Wang Zhou,Kang Shouyu,He Dawei,Liu Ruijiang
Magnetic α-Fe2O3/Fe3O4 heterostructure nanosheets were fabricated via hydrothermal calcination. The activity of penicillin G acylase (PGA), which was covalently immobilized onto silica-decorated heterostructure nanosheets, achieved the highest activity of 387.03 IU/g after 18 h of incubation with 0.1 ml of PGA. In contrast, the activity of free PGA reached the highest level when the temperature was 45°C with a pH of 8.0. However, the activity of free PGA changed more dramatically than immobilized PGA as the relative conditions changed. Moreover, the Michaelis–Menten constant (Km) and reusability of immobilized PGA were also explored. The results showed that free PGA Km and maximum rate (Vmax) were 0.0274 M and 1.167 μl/min, respectively. Km and Vmax values of immobilized PGA were 0.1082 M and 1.294 μl/min, respectively. After 12 cycles of repetitive use, immobilized PGA remained approximately 66% of its initial activity, indicating that the PGA immobilized onto the heterostructure nanosheets showed better stability and reusability than free PGA.
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APPLIED CATALYSIS A-GENERAL
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2021
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IF 5.706
Feng Wang,Lu Yu,Chao Li,Xiaofeng Xia,Fuming Zhang,Robert J. Linhardt
In this paper, a reusable heterogeneous catalyst of papain was prepared and used to catalyze the polymerization for oligo-glutamate. In silico, the 9,9-bis(2,3-epoxypropyl) fluorenyl group (DDI) carried on polystyrene beads (PS-PEG-DDI) showed site-specific binding for sites which are far away the active site of papain. The immobilization of papain on PS-PEG-DDI reached the optimal value of 126 ± 2.5 mg/g beads and 1726.2 ± 34 U/g beads at the papain/beads ratio of 1:5 in phosphate buffer (pH 8.0, 200 mM) at 45 °C for 4 h. The storage stability, pH stability, thermal stability, solvent tolerance and resistance to metal ions of papain were enhanced by the immobilization. The oligomerization of L -glutamic acid diethyl ester hydrochloride via PS-PEG-DDI immobilized papain in phosphate buffer (pH 8, 200 mM) at 45 °C demonstrated the yield of oligo(γ-ethyl-L-glutamate) reached 78.6 ± 1.2% under the conditions of 2 U/ml of papain, 60 mg/ml L -glutamic acid diethyl ester hydrochloride for 4 h. The immobilization increased the yield by about 40%. The analysis by mass spectrometry (MS) and 1 H NMR showed an average degree of polymerization (DP avg ) of product was approximately 7–8, identical to that produced using free papain. The biocatalytic activity of the PS-PEG-DDI immobilized papain remained stable after 5 repeated uses, all giving a yield of over 70%. The reduced activation energy of the reaction catalyzed by the PS-PEG-DDI immobilized papain suggests a more favorable active conformation was probably achieved following immobilization.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2021
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IF 6.953
Neng Xiong,Yan Dong,Dong Xie,Zi-qi Li,Ya-Ping Xue,Yu-Guo Zheng
In the chemical-biological synthesis route of gabapentin, immobilized Escherichia coli cells harboring nitrilase are used to catalyze the biotransformation of intermediate 1-cyanocyclohexaneacetonitile to 1-cyanocyclohexaneacetic acid. Herein, we present a novel cell immobilization method, which is based on cell adsorption using 75 g/L Escherichia coli cells and 6 g/L zeolite, cell crosslinking using 3 g/L polyethylenemine and biomimetic silicification using 18 g/L hydrolyzed tetramethylorthosilicate. The constructed “hybrid biomimetic silica particles (HBSPs)” with core-shell structure showed a specific activity of 147.2 ± 2.3 U/g, 82.6 ± 2.8% recovery of nitrilase activity and a half-life of 19.1 ± 1.9 h at 55 °C. 1-Cyanocyclohexaneacetonitrile (1.0 M) could be completely hydrolyzed by 50 g/L of HBSPs at pH 7.5, 35 °C in 4 h, providing 92.1 ± 3.2% yield of 1-cyanocyclohexaneacetic acid. In batch reactions, the HBSPs could be reused for 13 cycles and maintained 79.9 ± 4.1% residual activity after the 10th batch, providing an average product yield of 92.6% in the first 10 batches with a productivity of 619.3 g/L/day. In addition, multi-layer structures consisting of silica coating and polyethylenemine/glutaraldehyde crosslinking were constructed to enhance the mechanical strength of immobilized cells, and the effects of coating layers on the catalytic properties of immobilized cells was discussed.
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BIORESOURCE TECHNOLOGY
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2023
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IF 11.4
Jing-jing Guo,Yi-tong Wang,Zhen Fang
Magnetic biochar was synthesized via chelation of Fe 3+ with carboxymethyl cellulose and pyrolysis for covalently immobilizing Eversa® Transform lipase. The magnetic biochar had 75.8 mg/g lipase loading that was 54.1 % higher than that without magnetism. The immobilized lipase achieved 91.3 mg/g lipase loading with 19.2 U/mg lipase activity after optimization. It showed good thermal and acid stability with 82.5 % and 98.2 % relative activity at 45 °C and pH 4, respectively. Its relative activity was 90.8 % after stored for 30 d at 4 °C. After magnetically separated for 10 cycles, it still kept 70.1 % activity due to the strong covalent bonding. The lipase further catalyzed one-pot esterification and transesterification of high acid value oil (38 mg KOH/g) with 95.7 % biodiesel yield and cycled for 10 times at 85.7 % yield. Kinetic study gave the activation energy of 28.7 kJ/mol. The covalently immobilized lipase could find practical applications.
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COLLOIDS AND SURFACES B-BIOINTERFACES
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2021
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IF 5.268
Yao Zhang,Ling Zhu,Gangcheng Wu,Xingguo Wang,Qingzhe Jin,Xiguang Qi,Hui Zhang
In this study, hollow mesoporous silica cube (HMSC) modified with amino (-NH 2 ) were synthesized and applied in the immobilization of phospholipase D (PLD) via physical adsorption and chemical cross-linking strategy. The amino-functionalized nano carrier HMSC represented excellent immobilization ability and achieved 87.15 % immobilization rate. The immobilized PLD has wider pH application range and thermal stability, and maintained over 90% of the initial activity after incubation at 50 °C for 2 h. After 50 days of storage at 4 ℃, immobilized PLD retained 40.12 % of its initial activity while free PLD lost 88.28% of its initial activity. The modified HMSC with immobilized PLD (HMSC-NH 2 -PLD) retained 50.73% activities after 9 consecutive reuses. Using the HMSC-NH 2 -PLD, a high-efficient method for the conversion of phosphatidylserine (PS) from phosphatidylcholine (PC) and L-serine was proposed. The HMSC-NH 2 -PLD exhibited prominent enzymatic activity for PS synthesis, the maximal conversion of PS was 90.40% with a catalytic efficiency (CE) of 31.95 μmol / (g h under the optimal conditions. The research in this paper provides a sustainable and efficient biocatalysis application for PS synthesis.
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JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
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2026
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IF 1.7
Wang Xinyu,Qin Yilin,Gong Junyuan,Zhang Guohao,Peng Yinyin,Sun Gen,Ji Yanhao,Huang Yaling,Li Yahui,Nie Xiaoqin
This study aimed to enhance U(VI) removal from water by constructing a ternary system of Shewanella putrefaciens ( S. putrefaciens ), chlorite, and humic acid (HA). The ternary system achieved significantly higher U(VI) immobilization than single or binary systems, owing to synergistic effects of adsorption enrichment, electron shuttling, and bioreduction. Under optimal conditions, the U(VI) removal efficiency reached 91.6%. Importantly, pre-forming the ternary composite before U(VI) addition avoided false removal caused by HA-U(VI) complexation, ensuring accurate assessment of reductive immobilization. This work provides a reliable strategy for uranium-contaminated water remediation. Graphical abstract
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2023
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IF 9.9
Yangjie Li,Yirong Tian,Yu Fu,Liang Pang,Yang Li,Peng Xiao,Zhuan Li
Smart surface coatings have been proven to be an effective strategy to significantly enhance the electronic conductivity and cycling stability of silicon-based anode materials. However, the single/conventional coatings face critical challenges, including low initial Coulomb efficiency (ICE), poor cyclability, and kinetics failure, etc. Hence, we proposed a dual immobilization strategy to synthesize graphene supported anatase TiO 2 /carbon-coated porous silicon composite (denoted as PSi@TiO 2 @C/Graphene) using industrial-grade ferrosilicon as lithium storage raw materials through the simple etching, combined with sol–gel and hydrothermal coating processes. In this work, the dual immobilization from the “confinement effect” of the inner TiO 2 shell and the “synergistic effect” of the outer carbon shell, improves the kinetics of the electrochemical reaction and ensures the integrity of the electrode material structure during lithiation. Furthermore, the introduction of the graphene substrate offers ample space for dispersing and anchoring the Si-based granules, which in turn provides a stable 3D conductive network between the particles. As a result, the PSi@TiO 2 @C/Graphene electrode delivers high reversible capacity of 1605.4 mAh g −1 with 93.65% retention at 0.5 A g −1 after 100 cycles (vs. 4th discharge), high initial Coulomb efficiency (82.30%), and superior cyclability of 1159.9 mAh g −1 after 250 cycles. The above results suggest that the particle structure has great potential for applications in Si-based anode and may provide some inspiration for the design of other energy storage materials.
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JOURNAL OF MOLECULAR STRUCTURE
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2023
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IF 3.8
Di-Ming Chen,Xue-Jing Zhang
Acetylene is an important industrial material for the production of acetaldehyde, acetic acid, benzene, synthetic rubber, synthetic fiber, etc., and its separation from the gas mixtures of C 2 H 2 /CO 2 is of great importance but a challenging task due to their similar physical properties and molecular sizes. In this study, taking the advantage of open-donor sites on the pore surface as the nano-traps for C 2 H 2 molecules, a new microporous metal-organic framework (MOF) formulated as {[C o 3 (OH) 2 (HCOO) 2 (CPT) 2 ](NMF) 2 (MeOH) 3 (H 2 O)} n ( 1 , NMF = N - methylformamide) has been prepared by virtue of a bifunctional organic ligand 4-(4H-1,2,4-triazol-4-yl)benzoic acid (HCPT), which showed discriminating sorption performance toward C 2 H 2 (113 cm 3 /g at 298 K and 1 bar) over CO 2 (33 cm 3 /g) under the same conditions. The different sorption behavior of {[C o 3 (OH) 2 (HCOO) 2 (CPT) 2 ]} n between C 2 H 2 and CO 2 results in a high uptake ration (3.4:1) and IAST selectivity (13) at 298 K and 1 bar. Furthermore, the force-field based grand canonical Monte Carlo (GCMC) simulation results demonstrate that the large electronegativity and polarizability of open O donor sites on the pore surface contribute to its high C 2 H 2 /CO 2 separation performance, leading to its more favorable C 2 H 2 uptakes than CO 2 .
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Environmental Technology & Innovation
·
2021
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IF 5.263
Yansong Zhang,Zehai Yu,Yunshuang Hu,Caifeng Song,Fuwei Li,Wen He,Xiaofeng Wang,Zhixia Li,Hongfei Lin
Magnetic polyvinyl alcohol–sodium alginate–diatomite (PVA–SA-diatomite) composite carriers for immobilized microorganisms were prepared for removal of NH 4 + -N from effluents. The mass transfer efficiency, chemical stability, and NH 4 + -N removal efficiency of the carriers were investigated. The amount of each ingredient added significantly affected the performance of the carriers. The optimal concentrations of PVA, SA, diatomite , and Fe 3 O 4 were 10%, 1%, 1%, and 2%, respectively. The obtained carrier achieved a NH 4 + -N removal efficiency of 72.5% after reaction for 12 h, which was 31.8% higher than that with the non-magnetic carrier. The removal of NH 4 + -N was attributed to the cooperative action among non-magnetic ingredients, magnetic ingredients, and microorganisms. The adsorptions of NH 4 + -N by non-magnetic ingredients and Fe 3 O 4 contributed 21.2% and 25.5%, respectively, and microorganism metabolism contributed 53.2% to NH 4 + -N removal. The novel texture structure of the carrier leads to improved mass transfer of nutrients and stable activity of microorganisms. Nitrification followed the first-order reaction for low concentration of effluents and zero-order reaction for high concentration of effluents. The reaction rate increased with increasing initial NH 4 + -N concentration. The magnetic carrier was applicable for a long time. These results show the great potential of the developed carrier for industrial applications.
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