RESUMEN
Selectively achieving the photoreduction of carbon dioxide (CO2) to methane (CH4) remains a significant challenge, which primarily arises from the complexity of the protonation process. In this work, we designed metal-vacancy pair sites in defective metal oxide semiconductors, which anchor the reactive intermediates with a bridged linkage for the selective protonation to produce CH4. As an example, oxygen-deficient Nb2O5 nanosheets are synthesized, in which the niobium-oxygen vacancy pair sites are demonstrated by X-ray photoelectron spectroscopy and electron paramagnetic resonance spectra. In situ Fourier transform infrared spectroscopy monitors the *CH3O intermediate, a key intermediate for CH4 production, during the CO2 photoreduction in oxygen-deficient Nb2O5 nanosheets. Importantly, the built metal-vacancy pair sites regulate the *CH3O formation step as a spontaneous process, making the reduction of CO2 to CH4 the preferred method. Therefore, the oxygen-deficient Nb2O5 nanosheets exhibit a CH4 formation rate of 19.14 µmol g-1 h-1, with an electron selectivity of â¼94.1%.
RESUMEN
Nowadays, plastic waste threatens public health and the natural ecosystems of our lives. It is highly beneficial to recycle plastic waste in order to maximize the reuse of its contained carbon sources for the development of other valuable products. Unfortunately, traditional techniques usually require significant energy consumption and result in the generation of hazardous waste. Herein, the up-to-date developments on the "green" strategies under mild conditions including electrocatalysis, photocatalysis, and photoelectrocatalysis of plastic wastes are presented. During the oxidation of plastics in these "green" strategies, corresponding reduction reactions usually exist, which affect the property of catalytic plastics conversion. Particularly, we mainly focus on how to design the corresponding half reactions, such as the water reduction, carbon dioxide reduction, and nitrate reduction. Finally, we provide forward-looking insight into the enhancement of these "green" strategies, the extension of more half reactions into other organic catalysis, a comprehensive exploration of the underlying mechanisms through in situ studies and theoretical analysis and the problems for practical applications that needs to be solved.
RESUMEN
In this work, a trimetallic (Ni/Co/Zn) organic framework (tMOF), synthesized by a solvothermal method, was calcinated at 400 and 600 °C and the final products were used as a support for lipase immobilization. The material annealed at 400 °C (Ni-Co-Zn@400) had an improved surface area (66.01 m2/g) and pore volume (0.194 cm3/g), which showed the highest enzyme loading capacity (301 mg/g) with a specific activity of 0.196 U/mg, and could protect the enzyme against thermal denaturation at 65 °C. The optimal pH and temperature for the lipase were 8.0 and 45 °C but could tolerate pH levels 7.0-8.0 and temperatures 40-60 °C. Moreover, the immobilized enzyme (Ni-Co-Zn@Lipase, Ni-Co-Zn@400@Lipase, or Ni-Co-Zn@600@Lipase) could be recovered and reused for over seven cycles maintaining 80, 90, and 11% of its original activity and maintained a residual activity >90% after 40 storage days. The remarkable thermostability and storage stability of the immobilized lipase suggest that the rigid structure of the support acted as a protective shield against denaturation, while the improved pH tolerance toward the alkaline range indicates a shift in the ionization state attributed to unequal partitioning of hydroxyl and hydrogen ions within the microenvironment of the active site, suggesting that acidic residues may have been involved in forming an enzyme-support bond. The high enzyme loading capacity, specific activity, encouraging stability, and high recoverability of the tMOF@Lipase indicate that a multimetallic MOF could be a better platform for efficient enzyme immobilization.
Asunto(s)
Enzimas Inmovilizadas , Lipasa , Nanocompuestos , Zinc , Lipasa/química , Lipasa/metabolismo , Enzimas Inmovilizadas/química , Enzimas Inmovilizadas/metabolismo , Nanocompuestos/química , Concentración de Iones de Hidrógeno , Zinc/química , Estabilidad de Enzimas , Temperatura , Cobalto/química , Níquel/química , Aleaciones/química , Estructuras Metalorgánicas/químicaRESUMEN
In this study, we proposed a method for fabricating Janus sheets using biological "microflowers" as a sacrificial template. The microflower-templated Janus sheets (MF-JNSs) were employed as a foam stabilizer in foam separation of the whey soybean protein (WSP). The MF-JNSs took inorganic hybrid microflowers (BSA@Cu3 (PO4)2-MF) as template, followed by the sequential attachment of protamine and silica to the surface of the BSA@Cu3(PO4)2-MF. Subsequently, the template was removed using ethylenediaminetetraacetic acid after the silicon dioxide was modified by 3-(methacryloyloxy) propyl trimethoxysilane. Upon template dissolution, the modified silica layer, lacking support from the core, fractured to form the MF-JNSs. This method omitted the step of treating the hollow ball by external force and obtained Janus sheets in one step, indicating that it was simple and feasible. The morphology, structure, and composition of the MF-JNSs were analyzed by SEM, TEM, AFM, XRD, and FT-IR. The MF-JNSs were found to delay the breakage time of the Pickering emulsion, demonstrating their emulsion stabilizing capability. Importantly, they significantly enhanced the foam half-life and foam height of soybean whey wastewater (SWW). Moreover, the recovery percentage and enrichment ratio of WSP, separated from SWW by foam separation, were improved to 81 ± 0.28 and 1.20 ± 0.05%, respectively.
RESUMEN
The current study presents a scalable approach for the preparation of temperature-responsive PEG/SiO2/PNIPAM-PEA Janus particles and, for the first time, investigates their potential applications in stabilizing foam and defoaming by adjusting the temperature. The method utilizes a (W1 + O)/W2 emulsion system, which incorporates appropriate surfactants to stabilize the emulsion and prevent rapid dissolution of the hydrophilic triblock polymer PEG-b-PTEPM-b-PNIPAM in water. The PEG/SiO2/PNIPAM-PEA Janus particles with temperature-responsive characteristics were synthesized in a single step that combined the sol-gel reaction and photoinduced free radical polymerization. The contact angle of the hydrophilic PEG/SiO2/PNIPAM surface was measured to be 54.7 ± 0.1°, while the contact angle of the hydrophobic PEA surface was found to be 122.4 ± 0.1°. By incorporating PEG/SiO2/PNIPAM-PEA Janus particles at a temperature of 25 °C, the foam's half-life is significantly prolonged from 42 s to nearly 30 min. However, with an increase in temperature to 50 °C, the foam's half-life rapidly diminished to only 44 s. This innovative application effectively enhances foam stabilization at low temperatures and facilitates the rapid dissipation of foam at high temperatures.
RESUMEN
This paper reports an innovative study that aims to address key issues in the efficient recycling of wastepaper cellulose. The research team utilized the temperature-responsive upper critical solution temperature (UCST) polymer P(NAGA-b-DMA) in combination with the LytA label's affinity for choline analogs. This innovative approach enabled them to successfully develop a novel soluble immobilized enzyme, P(NAGA-b-DMA)-cellulase. This new enzyme has proven highly effective, significantly enhancing the degradation of wastepaper cellulose while demonstrating exceptional stability. Compared with the traditional insoluble immobilized cellulase, the enzyme showed a significant improvement in the pH, temperature stability, recycling ability, and storage stability. A kinetic parameter calculation showed that the enzymatic effectiveness of the soluble immobilized enzyme was much better than that of the traditional insoluble immobilized cellulase. After the immobilization reaction, the Michaelis constant of the immobilized enzyme was only increased by 11.5%. In the actual wastepaper degradation experiment, the immobilized enzyme was effectively used, and it was found that the degradation efficiency of wastepaper cellulose reached 80% of that observed in laboratory conditions. This novel, thermosensitive soluble immobilized cellulase can efficiently catalyze the conversion of wastepaper cellulose into glucose under suitable conditions, so as to further ferment into environmentally friendly biofuel ethanol, which provides a solution to solve the shortage of raw materials and environmental protection problems in the paper products industry.
Asunto(s)
Celulasa , Enzimas Inmovilizadas , Enzimas Inmovilizadas/metabolismo , Celulosa/metabolismo , Celulasa/metabolismo , Temperatura , Polímeros , HidrólisisRESUMEN
Most ovarian cancer patients are chemosensitive initially, but finally relapse with acquired chemoresistance. Multidrug-resistance is the extremely terrible situation. The mechanism for the acquired chemoresistance of ovarian cancer patients is still not clear. LncRNAs have been recognized as the important regulator of a variety of biological processes, including the multidrug-resistant process. Here, we carried out the lncRNA sequencing of the ovarian cancer cell line A2780 and the paxitaxel resistant cell line A2780/PTX which is also cross resistant to the cisplatin and epirubicin. Through integrating the published data with the cisplatin resistant lncRNAs in ovarian cancer cell line or ovarian cancer patients, 5 up-regulated and 21 down-regulated lncRNAs are considered as the multidrug-resistant lncRNAs. By real-time PCR analysis, we confirmed the 5 up-regulated and 4 down-regulated multidrug resistant lncRNAs were similarly changed in both the multidrug resistant ovarian cancer cell lines and the multidrug resistant colon cancer cell lines. Furthermore, we conducted the lncRNA-mRNA co-expression network to predict the potential multidrug resistant lncRNAs' targets. Interestingly, the multidrug resistant genes ABCB1, ABCB4, ABCC3, and ABCG2 are all co-expressed with lncRNA CTD-2589M5.4. Our results provide the valuable information for the understanding of the lncRNA function in the multidrug resistant process.
Asunto(s)
Antineoplásicos/farmacología , Biomarcadores de Tumor/genética , Resistencia a Múltiples Medicamentos/genética , Resistencia a Antineoplásicos/genética , Neoplasias Ováricas/tratamiento farmacológico , Neoplasias Ováricas/genética , ARN Largo no Codificante/genética , Subfamilia B de Transportador de Casetes de Unión a ATP/genética , Subfamilia B de Transportador de Casetes de Unión a ATP/metabolismo , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 2/genética , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 2/metabolismo , Línea Celular Tumoral , Cisplatino/farmacología , Neoplasias del Colon/tratamiento farmacológico , Neoplasias del Colon/genética , Neoplasias del Colon/metabolismo , Neoplasias del Colon/patología , Biología Computacional , Bases de Datos Genéticas , Epirrubicina/farmacología , Femenino , Perfilación de la Expresión Génica/métodos , Regulación Neoplásica de la Expresión Génica , Redes Reguladoras de Genes , Humanos , Proteínas Asociadas a Resistencia a Múltiples Medicamentos/genética , Proteínas Asociadas a Resistencia a Múltiples Medicamentos/metabolismo , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Neoplasias Ováricas/metabolismo , Neoplasias Ováricas/patología , Paclitaxel/farmacología , ARN Largo no Codificante/metabolismoRESUMEN
The tumor suppressor gene, AT Rich Interactive Domain 1A (ARID1A) mutation has been reported in a variety of cancers, especially the endometrium-related gynecological cancers, including the ovarian clear cell carcinoma, ovarian endometrioid carcinoma, and uterine endometrioid carcinoma. However, the prognostic value of ARID1A in endometrium-related gynecological cancers is still inconclusive. Therefore, we performed this meta-analysis to evaluate the clinical significance of ARID1A in endometrium-related gynecological cancers. By systematically searching all the relevant studies from Pubmed, Cochrane Library, and Web of Science up to September 2016, 11 studies with 1,432 patients were included. All the study characteristics and the prognostic data were extracted. Hazard ratios (HRs) and 95% confidence intervals (CIs) were pooled using the fixed-effect or random-effect model. Our results indicated that negative ARID1A expression predicted shorter Progression free survival (PFS, HR, 1.84; 95%CI, 1.32-2.57, P = 0.000) of patients with endometrium related gynecological cancers, especially the patiently with OCCC and the patients in Japan. Besides, a marginal trend towards the same direction was found in the Overall analysis (OS, HR, 1.34; 95%CI, 0.93-1.93, P = 0.112). Furthermore, the significant correlation was achieved between the negative ARID1A expression and the FIGO stage of endometrium-related gynecological cancers, but not the other characteristics. J. Cell. Biochem. 118: 4517-4525, 2017. © 2017 Wiley Periodicals, Inc.
Asunto(s)
Adenocarcinoma de Células Claras , Carcinoma Endometrioide , Neoplasias Endometriales , Proteínas de Neoplasias/metabolismo , Proteínas Nucleares/metabolismo , Neoplasias Ováricas , Factores de Transcripción/metabolismo , Adenocarcinoma de Células Claras/metabolismo , Adenocarcinoma de Células Claras/mortalidad , Adenocarcinoma de Células Claras/patología , Carcinoma Endometrioide/metabolismo , Carcinoma Endometrioide/mortalidad , Carcinoma Endometrioide/patología , Proteínas de Unión al ADN , Supervivencia sin Enfermedad , Neoplasias Endometriales/metabolismo , Neoplasias Endometriales/mortalidad , Neoplasias Endometriales/patología , Femenino , Humanos , Neoplasias Ováricas/metabolismo , Neoplasias Ováricas/mortalidad , Neoplasias Ováricas/patología , Tasa de SupervivenciaRESUMEN
PURPOSE: To explore the optimal treatment for cesarean scar pregnancy. METHOD: In total, 86 women diagnosed with a cesarean scar pregnancy were divided into three groups according to treatment. The human chorionic gonadotrophin (hCG) decline percentage, intraoperative blood loss and success rate were analyzed in Group A [combination of uterine arterial embolization (UAE), local methotrexate (MTX) injection and dilation & curettage (D&C)], Group B (combination of UAE and local MTX injection) and Group C (D&C). Then, the best treatment was carefully analyzed, and recommendations were provided. RESULTS: The success rate was highest in Group A (97.5%) compared with Group B (76%) and Group C (63.15%). The reduction in hCG was greatest in Group A (86.62%, 44.0-99.97%) compared with group B (67.83%, 18.0-98.03%) and Group C (68.21%, 27.0-93.24%). The intraoperative blood loss was lowest in Group A (44.881, 5-200 ml) compared with Group C (224.737, 10-1000 ml). Additionally, we found that the best time to perform D&C in group A depended on the hCG reduction percentage, and a 35% reduction after UAE and local MTX injection could be used as the indicator to perform D&C. CONCLUSIONS: The combination of UAE, local MTX injection and D&C for CSP patients is the optimal treatment strategy. A 35% reduction in hCG after UAE and local MTX injection can be recommended as the indicator to perform D&C.
Asunto(s)
Aborto Inducido/métodos , Cicatriz/patología , Embarazo Ectópico/cirugía , Adulto , Pérdida de Sangre Quirúrgica , Cesárea , Bases de Datos Factuales , Dilatación y Legrado Uterino , Femenino , Humanos , Metotrexato/administración & dosificación , Metotrexato/uso terapéutico , Embarazo , Embarazo Ectópico/patología , Estudios Retrospectivos , Útero/cirugíaRESUMEN
Background: Timely diagnosis is the key factor to improve the prognosis of endometrial carcinoma (EC). To date, no particularly good markers could significantly improve the detection rate of EC. This study aimed to assess the utility of serum markers homocysteine (Hcy), human epididymal protein 4 (HE4), cancer antigen 199 (CA199), cancer antigen 125 (CA125), fibrinogen (Fib), and D-dimer (D-D) for EC diagnosis, especially Hcy of which its role in EC has not been noticed. Methods: Pre-test and verification tests were performed. In Pre-test, the diagnostic value of the included markers was evaluated and the right marker was chosen to establish an efficient new risk index for screening EC. In verification tests, the applicability of the new risk index was tested. Several evaluation indices including receiver operating characteristic (ROC) curve, Youden Index, sensitivity (SN), and specificity (SP), were adopted to assess the diagnostic value of the included markers for EC. Results: Hcy may be useful in the diagnosis of EC. Its diagnostic value was not significantly lower than that of HE4. Based on the diagnostic value of Hcy and HE4, a new risk index was established, which demonstrated high value in EC diagnosis (ROC, 0.801), especially among young female patients (age ≤50 years, ROC, 0.871). Furthermore, the level of Hcy, but not HE4, was notably different in normal or benign endometrial lesions, atypical endometrial hyperplasia (AEH), and EC. Conclusions: The change of Hcy levels could be used to diagnose EC and when taken into consideration together with the detection of HE4, the diagnostic accuracy of EC is further improved.
RESUMEN
A nonmetallic composite photocatalyst with 2D/2D structure was prepared by hydrothermal in-situ polymerization and used for the immobilization of cytochrome C (Cyt c). The photo-enzyme coupling system has a very high enzyme load, which can reach 528.29 mg g-1 after optimization. Compared with free Cyt c, Cytc/PEDOT/CN showed better enzymatic activity, stability and catalytic efficiency. Even after being stored at 100 °C for 60 min, the enzyme activity remained at 49.42 % and remained at 57.89 % after 8 cycles. Moreover, Cytc0.5/PEDOT3/CN showed excellent photocatalytic degradation performance in the degradation experiment of bisphenol A (BPA), reaching 68.22 % degradation rate within 60 min, which was 3.9 times higher than that of pure g-C3N4 and 1.61 times higher than that of pure PEDOT3/CN. This study shows that the introduction of conductive polymers is of great significance to the photo-enzyme coupling system and provides a new strategy for the treatment of phenol-containing wastewater.
Asunto(s)
Compuestos de Bencidrilo , Fenoles , Agua , Fenoles/química , Nitrilos , CatálisisRESUMEN
This work describes the synthesis of fibrous nickel-based metal organic framework (Ni-ZIF) via simple solvothermal method. The material formed was calcinated at 400, 600, 800 °C to improve its surface area, porosity and enzyme binding capacity. Changes in X-ray diffraction pattern after calcination revealed the Ni-ZIF transitioned from amorphous to crystalline structure. The surface area, pore volume and pore size for Ni-ZIF@600 were found to be 312.15 m2/g, 0.88 cm3/g and 10.28 nm, with an enzyme loading capacity of 593.85 mg/g after 30 h The free (ß-Gal-LEH) and immobilized ß-Galactosidase were stable at pH 7.5, temperature 50 °C, and yielded 70.70 and 63.95 mM glucose after milk lactose hydrolysis, respectively. The Ni-ZIF@600@ß-Gal-LEH exhibited high enzyme retention capacity, maintaining 59.44 % of its original activity after 6-cycles. The enhanced magnetic property, enzyme binding capacity and easy recoverability of the calcinated Ni-ZIF could guarantee its industrial significance as immobilization module for enzyme-mediated catalysis.
Asunto(s)
Enzimas Inmovilizadas , Níquel , Níquel/química , Enzimas Inmovilizadas/química , Temperatura , beta-Galactosidasa/química , Fenómenos MagnéticosRESUMEN
Solar-driven plastics conversion into valuable fuels has attracted broad attention in recent years, which has enormous potential for plastics recycling in the future. However, it usually encounters low conversion efficiency, where one of the reasons is attributed to the poor carrier dynamics in the photocatalytic process. In this Perspective, we critically review the developed strategies, involving defect engineering, doping engineering, heterojunction engineering, and composite construction, for boosted carrier separation efficiency. In addition, we provide an outlook for more potential strategies to engineer catalysts for promoted carrier dynamics. Finally, we also propose prospects for the future research direction of plastics photoconversion into fuels.
RESUMEN
Background: Ovarian cancer (OC) is often diagnosed at an advanced stage due to the absence of specific symptoms in its early stages. And the prognosis greatly depends on when the disease is diagnosed. Thus, we conducted to evaluate the value of preoperative fibrinogen (Fib) levels for the diagnosis of OC in the hope of improving its diagnostic efficiency. Methods: A total of 126 ovarian tumor patients were retrospectively included in this study. Four candidate OC markers, including cancer antigen 125 (CA125), Fib, platelet (PLT) and homocysteine (Hcy) were employed to establish a diagnosis model for OC. The diagnostic performance of the model was evaluated using the area under the receiver operating characteristic curve (AUC) and Youden index. Results: All included markers could be used for the diagnosis of OC. The AUCs of CA125, Fib, PLT and Hcy were 0.881, 0.825, 0.676 and 0.647, respectively. The new diagnosis model combining CA125 and Fib (CA125-Fib) had a higher AUC (0.924), Youden index (0.730), and best sensitivity (SN) (74.6%) and specificity (SP) (98.41%). CA125-Fib also had a high value in the diagnosis of stage I-II OC (AUC, Youden index, SN and SP: 0.853, 0.624, 81.48% and 80.95%). Conclusions: Fib could be used for OC diagnosis. In particular, the combination of Fib and CA125 could further improve the diagnostic efficiency. And the diagnostic value of PLT and Hcy was found to be poor.
RESUMEN
The aim of this study was to separate and purify recombinant ß-glucosidase (GLEGB) with elastin-like polypeptide (ELP) and graphene-binding peptide (GB) from cell lysis solution by foam separation and further purification. The study of foam property of GLEGB cell lysis solution indicated that it had excellent foaming property and foam stability, which was suitable for foam separation. This could be due to the GB tag with hydrophobicity, which made the recombinant ß-glucosidase with GB preferentially adsorb on the surface of bubbles. At optimum operating conditions of foam separation, the enzyme activity recovery of GLEGB could reach 95.63 ± 1.0%. The foam solution of GLEGB was further purified based on the thermally responsive property of the ELP tag, and the purification fold of GLEGB could reach 29.6 ± 0.5 at the optimum operating conditions. The prominent purification effect indicates that this technique is a simple and efficient technique for the separation and purification of recombinant enzymes.
RESUMEN
A novel immobilized enzyme driven by visible light was prepared and used for complete mineralization of antibiotics in water bodies. The immobilized enzyme was composed of carbon nitride modified by biochar (C/CN) and horseradish peroxidase (HRP), establishing the photo-enzyme coupling system with synergistic effect. Among them, the introduction of biochar not only improves the stability and loading capacity of the enzyme, but also improves the light absorption capacity and carrier separation efficiency of the photocatalyst. After the optimization of immobilization process, the solid load of HRP could reach 251.03 mg/g, and 85.03 % enzyme activity was retained after 18 days of storage at 4 °C. In the sulfadiazine (SDZ) degradation experiment, the degradation rate of HRP/C3/CN reached 71.21 % within 60 min, which was much higher than that of HRP (2.33 %), CN (49.78 %) and C3/CN (58.85 %). In addition, under the degradation of HRP/C/CN, the total organic carbon (TOC) removal rate of SDZ reached 53.14 %, which was 6.47 and 1.74 times that of CN and C3/CN, respectively. This study shows that the introduction of biochar is of great significance to the photo-enzyme cascade coupling system and provides a new strategy for the application of HRP&g-C3N4 system in wastewater treatment.
Asunto(s)
Enzimas Inmovilizadas , Agua , Enzimas Inmovilizadas/metabolismo , Sulfadiazina , Peroxidasa de Rábano Silvestre/metabolismo , LuzRESUMEN
Objective: To investigate the incidence of pelvic floor dysfunction (PFD) and electrophysiological indicators in postpartum women at 6-8 weeks and explore the influence of demographic characteristics and obstetric factors. Methods: A survey questionnaire collected information about the conditions of women during their pregnancy and puerperal period and their demographic characteristics; pelvic organ prolapse quantitation (POP-Q) and pelvic floor muscle electrophysiology (EP) examination were conducted in postpartum women at 6-8 weeks. Results: Vaginal delivery was a risk factor for anterior pelvic organ prolapse (POP) (OR 7.850, 95% confidence interval (CI) 5.804-10.617), posterior POP (OR 5.990, 95% CI 3.953-9.077), anterior and posterior stage II POP (OR 6.636, 95% CI 3.662-15.919), and postpartum urinary incontinence (UI) (OR 6.046, 95% CI 3.894-9.387); parity was a risk factor for anterior POP (OR 1.397,95% CI 0.889-2.198) and anterior and posterior stage II POP (OR 4.162, 95% CI 2.125-8.152); age was a risk factor for anterior POP (OR 1.056, 95% CI 1.007-1.108) and postpartum UI (OR 1.066, 95% CI 1.014-1.120); body mass index (BMI) was a risk factor for postpartum UI (OR 1.117, 95% CI 1.060-1.177); fetal birth weight was a risk factor for posterior POP (OR 1.465, 95% CI 1.041-2.062); and the frequency of pregnancy loss was a risk factor for apical POP (OR 1.853, 95% CI 1.060-3.237). Conclusion: Pelvic floor muscle EP is a sensitive index of early pelvic floor injury. The changes in muscle strength and fatigue degree coexist in different types of postpartum PFD, and each has its own characteristics.
RESUMEN
This work was developed to solve the problems of the restriction of non-specific adsorption and time-dependent denaturation in the purification of recombinant proteins by multistage chromatographic procedures. A novel purification method (ATPF-ITC) which combining aqueous two-phase flotation (ATPF) with inverse transition cycling (ITC) was established and used to efficiently purify recombinant ß-glucosidase (GLEGB) from cell lysis solution. First, GLEGB would preferentially adsorb on the nitrogen bubble interface relied on the hydrophobic property of the graphene-binding (GB) tag and enter into the top phase of ATPF. Second, GLEGB was achieved further purification by one-round ITC method based on the thermosensitive of the elastin-like polypeptide (ELP) tag. Consequently, the enzymatic activity recovery of GLEGB was 124.92% ± 0.83%, and the purification factor reached 24.26 ± 0.22. The purification results remained stable after six polymer cycles, and the process of ATPF-ITC had no negative effect on the structure of recombinant protein.
Asunto(s)
Escherichia coli , beta-Glucosidasa , Péptidos , Proteínas Recombinantes de FusiónRESUMEN
The development of a suitable immobilization strategy to improve the performance of immobilized glucose isomerase for the isomerization of glucose to fructose is crucial to promoting the industrial production of high-fructose syrup. In this work, a novel recyclable upper critical solution temperature (UCST)-type mVBA-b-P(AAm-co-AN)@glucose isomerase biocatalyst (PVAA@GI) was prepared, and the immobilized glucose isomerase could capture the glucose substrate through the affinity of 4-vinylbenzeneboronic acid (4-VBA) and the glucose substrate, which led to the enhanced substrate affinity and catalytic efficiency of the PVAA@GI. The biocatalyst exhibited excellent stability in pH, thermal, storage, and recycling compared to the free enzyme. The mVBA-b-P(AAm-co-AN)@glucose isomerase biocatalyst displayed reversibly soluble-insoluble characteristics with temperature change, which was in the soluble state during the enzyme reaction process but could be recovered in an insoluble form by lowering the temperature after the reaction. The highest fructose production rate reached 62.79%, which would have potential application in the industrial production of high-fructose syrup.
Asunto(s)
Isomerasas Aldosa-Cetosa , Fructosa , Glucosa , Temperatura , Isomerismo , Enzimas Inmovilizadas/metabolismo , Isomerasas Aldosa-Cetosa/metabolismoRESUMEN
In this study, the upper critical solution temperature (UCST)-responsive polymers poly (ethylene oxide) monomethyl ether-block-poly(acrylamide-co-acrylonitrile) (PEG-b-p(AAM-co-AN) were synthesized and successfully utilized to immobilize ß-glucosidase in crude enzyme solution. These UCST-responsive ß-glucosidase biocatalysts (PEG-b-p(AAM-co-AN@LytA-Glu) have specific UCST with tunable transition temperature, which could be tuned the separation temperature to the desired temperature range. The P2 @ LytA-Glu with an UCST of about 42.9 â was exploited by one-step covalent immobilization of ß-glucosidase in crude enzyme solution. The prepared P2 @ LytA-Glu exhibited significantly improved temperature, pH, storage, and operation stabilities compared with that of free enzyme. The catalytic rate of P2 @ Glu-LytA was 14.5% higher than that of P2-Glu (immobilized pure ß-glucosidase), which indicated that one-step immobilization of crude enzyme directly from crude enzyme solution was feasible, and it can greatly save the purification step and reduce the experimental cost. The engineered UCST-responsive immobilized enzymes are potentially useful for the practical green biocatalysis.