M. Rangel, C. Virgens, F. Mayer, A. Oliveira, M. Carvalho
Catalytic pyrolysis is an attractive alternative for converting biomass into energy and chemicals to replace fossil sources. This has encouraged the search for efficient catalysts that can directly remove oxygenated products during pyrolysis, since they are the main problem in the processing and use of the products obtained. The catalytic and non-catalytic pyrolysis of medium density fiber (MDF) over beta zeolite-supported nickel (3 and 5%) was performed using the biomass/catalyst of 1.0/0.2 ratio. The thermokinetic and thermodynamic parameters were determined using the isoconversional and non-isothermal methods of Flynn-Wall-Ozawa (FWO), Kissinger-Ahakira-Sunose (KAS) and Friedman. In addition, the master plots by the Criado method were used to determine the most suitable theoretical solid-state mechanism. The thermodynamic parameters were also obtained using the Friedman method. The results showed that the addition of the catalyst decreased the activation energy and affected the initial, final and maximum decomposition temperatures, which was related to the superficial acidic sites of beta zeolite that promote cracking and hydrocracking reactions. Nickel further decreased this parameter due to the activity of this metal in hydrodeoxygenation/deoxygenation, oligomerization and dehydration. The Friedman method provided the best correlation coefficient among the methods and was used to determine the thermodynamic parameters. The results showed that Ea increases in the order: MB3Ni < MB5Ni < MB < M.
{"title":"Thermokinetic and Thermodynamic Parameters for Catalytic Pyrolysis of Medium Density Fiber over Ni/Beta Zeolite","authors":"M. Rangel, C. Virgens, F. Mayer, A. Oliveira, M. Carvalho","doi":"10.21926/cr.2204038","DOIUrl":"https://doi.org/10.21926/cr.2204038","url":null,"abstract":"Catalytic pyrolysis is an attractive alternative for converting biomass into energy and chemicals to replace fossil sources. This has encouraged the search for efficient catalysts that can directly remove oxygenated products during pyrolysis, since they are the main problem in the processing and use of the products obtained. The catalytic and non-catalytic pyrolysis of medium density fiber (MDF) over beta zeolite-supported nickel (3 and 5%) was performed using the biomass/catalyst of 1.0/0.2 ratio. The thermokinetic and thermodynamic parameters were determined using the isoconversional and non-isothermal methods of Flynn-Wall-Ozawa (FWO), Kissinger-Ahakira-Sunose (KAS) and Friedman. In addition, the master plots by the Criado method were used to determine the most suitable theoretical solid-state mechanism. The thermodynamic parameters were also obtained using the Friedman method. The results showed that the addition of the catalyst decreased the activation energy and affected the initial, final and maximum decomposition temperatures, which was related to the superficial acidic sites of beta zeolite that promote cracking and hydrocracking reactions. Nickel further decreased this parameter due to the activity of this metal in hydrodeoxygenation/deoxygenation, oligomerization and dehydration. The Friedman method provided the best correlation coefficient among the methods and was used to determine the thermodynamic parameters. The results showed that Ea increases in the order: MB3Ni < MB5Ni < MB < M.","PeriodicalId":178524,"journal":{"name":"Catalysis Research","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134322244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alexandre Pradal, G. Poli, Julie Oble., A. Schallmey, Simona Bassoli
A two-step protocol for the synthesis of aryl-3-hydroxypropanones, which were regarded as lignin degradation products, was proposed herein. This protocol provided a more rapid and easier access to aryl-3-hydroxypropanones, and aryl-3-hydroxypropanones were expected to be ideal platform molecules for the synthesis of more complex value-added targets.
{"title":"Short Hydroacylation-Based Synthesis of Four Aryl-3-hydroxypropanones, Predictable Biomass-Derived C9 Platform Molecules","authors":"Alexandre Pradal, G. Poli, Julie Oble., A. Schallmey, Simona Bassoli","doi":"10.21926/cr.2204036","DOIUrl":"https://doi.org/10.21926/cr.2204036","url":null,"abstract":"A two-step protocol for the synthesis of aryl-3-hydroxypropanones, which were regarded as lignin degradation products, was proposed herein. This protocol provided a more rapid and easier access to aryl-3-hydroxypropanones, and aryl-3-hydroxypropanones were expected to be ideal platform molecules for the synthesis of more complex value-added targets.","PeriodicalId":178524,"journal":{"name":"Catalysis Research","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115366239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, we found that adding catalytic cracking feedstock, vacuum gas oil, and naphthenic acids in the amount of 0.005–0.0075% vol. increased the liquid target fractions, i.e., gasoline and light gas oil. The decrease in the yield of hydrocarbon gas at a practically constant degree of conversion of the raw material indicated a small proportion of the reactions of re-cracking of the resulting products. This also indicated the resource-saving nature of the process, allowing a larger amount of gasoline fraction and light gas oil to be obtained, as well as, reducing the amount of coke formed on the catalyst at a constant volume of processed feedstock.
{"title":"The Effect of Oxygen-containing Additives in Feedstock on the Performance of the Catalytic Cracking Process","authors":"E. Guseinova, S. Safarova","doi":"10.21926/cr.2204037","DOIUrl":"https://doi.org/10.21926/cr.2204037","url":null,"abstract":"In this study, we found that adding catalytic cracking feedstock, vacuum gas oil, and naphthenic acids in the amount of 0.005–0.0075% vol. increased the liquid target fractions, i.e., gasoline and light gas oil. The decrease in the yield of hydrocarbon gas at a practically constant degree of conversion of the raw material indicated a small proportion of the reactions of re-cracking of the resulting products. This also indicated the resource-saving nature of the process, allowing a larger amount of gasoline fraction and light gas oil to be obtained, as well as, reducing the amount of coke formed on the catalyst at a constant volume of processed feedstock.","PeriodicalId":178524,"journal":{"name":"Catalysis Research","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133295203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Biodiesel is derived from renewable vegetable or animal sources and is either used as a standalone fuel or blended with oil-based diesel. The kinetic mechanism of the esterification of oleic acid was investigated in a conventional batch reactor and a batch reactor coupled to a water adsorption system. The esterification was performed with oleic acid and methanol at different temperatures (70 to 110 °C) and alcohol-to-oleic acid molar ratios (3:1 to 9:1), using sulfuric acid as a catalyst. A kinetic model was constructed and validated. The model was statistically significant at a 95% confidence level, thus proving its effectiveness in predicting oleic acid esterification with methanol using sulfuric acid as a catalyst.
{"title":"Kinetic Modeling of the Esterification of Oleic Acid and Methanol in Conventional and Adsorptive Reaction Systems","authors":"F. Fernandes","doi":"10.21926/cr.2204034","DOIUrl":"https://doi.org/10.21926/cr.2204034","url":null,"abstract":"Biodiesel is derived from renewable vegetable or animal sources and is either used as a standalone fuel or blended with oil-based diesel. The kinetic mechanism of the esterification of oleic acid was investigated in a conventional batch reactor and a batch reactor coupled to a water adsorption system. The esterification was performed with oleic acid and methanol at different temperatures (70 to 110 °C) and alcohol-to-oleic acid molar ratios (3:1 to 9:1), using sulfuric acid as a catalyst. A kinetic model was constructed and validated. The model was statistically significant at a 95% confidence level, thus proving its effectiveness in predicting oleic acid esterification with methanol using sulfuric acid as a catalyst.","PeriodicalId":178524,"journal":{"name":"Catalysis Research","volume":"s3-3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130123456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Manal Al-Eid, Essa I. Alnaimi, A. Alqarawi, Rasha A. Al-Ghamdi, E. Al-Shafei, Donya A. Sewdan, Lianhui Ding
Parent ZSM-5 and Ga-modified ZSM-5 catalysts with different Si/Al ratios and particle sizes were prepared. The physicochemical properties of the prepared catalysts were investigated by performing X-ray powder diffraction analysis, BET surface area analysis, and NH3-TPD analysis. The performance of the aromatization reaction of the prepared catalysts was evaluated with 1-hexane as a model compound. The zeolite catalysts with a low SiO2/Al2O3 ratio possessed better activity than those with a high SiO2/Al2O3 ratio. Ga modification significantly improved the catalyst aromatization selectivity. Through aromatization, the acid sites of Ga-modified nano-sized zeolites promoted the selective conversion of produced olefin to aromatics by removing H-atoms. For the parent ZSM-5 and Ga-modified catalysts, the catalyst stability increased with an increase in the SiO2/Al2O3 molar ratio. The nano-sized ZSM-5 catalyst with a high SiO2/Al2O3 ratio exhibited better catalytic stability than the microscale ZSM-5, and the nano-sized catalyst with a low SiO2/Al2O3 ratio showed very low stability.
{"title":"Effect of ZSM-5 Particle Size and Framework Silica-to-Alumina Ratio on Hexane Aromatization","authors":"Manal Al-Eid, Essa I. Alnaimi, A. Alqarawi, Rasha A. Al-Ghamdi, E. Al-Shafei, Donya A. Sewdan, Lianhui Ding","doi":"10.21926/cr.2204035","DOIUrl":"https://doi.org/10.21926/cr.2204035","url":null,"abstract":"Parent ZSM-5 and Ga-modified ZSM-5 catalysts with different Si/Al ratios and particle sizes were prepared. The physicochemical properties of the prepared catalysts were investigated by performing X-ray powder diffraction analysis, BET surface area analysis, and NH<sub>3</sub>-TPD analysis. The performance of the aromatization reaction of the prepared catalysts was evaluated with 1-hexane as a model compound. The zeolite catalysts with a low SiO<sub>2</sub>/Al<sub>2</sub>O<sub>3</sub> ratio possessed better activity than those with a high SiO<sub>2</sub>/Al<sub>2</sub>O<sub>3</sub> ratio. Ga modification significantly improved the catalyst aromatization selectivity. Through aromatization, the acid sites of Ga-modified nano-sized zeolites promoted the selective conversion of produced olefin to aromatics by removing H-atoms. For the parent ZSM-5 and Ga-modified catalysts, the catalyst stability increased with an increase in the SiO<sub>2</sub>/Al<sub>2</sub>O<sub>3</sub> molar ratio. The nano-sized ZSM-5 catalyst with a high SiO<sub>2</sub>/Al<sub>2</sub>O<sub>3</sub> ratio exhibited better catalytic stability than the microscale ZSM-5, and the nano-sized catalyst with a low SiO<sub>2</sub>/Al<sub>2</sub>O<sub>3</sub> ratio showed very low stability.","PeriodicalId":178524,"journal":{"name":"Catalysis Research","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115464876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Singh, A. Chandra, Sakshi Kansal, Subrata Ghosh, S. Mishra, Dinesh Kumar, Shivam Porwal, Binita Boro
Solar cells based on organic-inorganic lead halide perovskites are popular in the photovoltaic community due to their high efficiency, low cost, and solution processability. Understanding the fundamentals of metal halide perovskite and its interfaces is extremely important for achieving high-quality materials and developing efficient devices using these materials with the necessary properties. Various methodologies have been used to evaluate the excellent optoelectronic properties, efficiency, and stability of PSCs. In this article, we reviewed the case studies of characterization techniques to investigate structural, optical, and electrical properties of perovskite material via electron microscopic techniques (SEM and TEM), J-V measurements, AFM, XRD, and spectroscopy techniques (PL, UV-vis, XPS, Raman, FTIR, and EIS). PSCs also need to have long-term stability and large-scale applicability for successful commercialization. In this review, we studied perovskite in detail to understand the key properties of the materials to facilitate the commercialization of PSCs.
{"title":"Perovskite Solar Cells: Assessment of the Materials, Efficiency, and Stability","authors":"T. Singh, A. Chandra, Sakshi Kansal, Subrata Ghosh, S. Mishra, Dinesh Kumar, Shivam Porwal, Binita Boro","doi":"10.21926/cr.2204033","DOIUrl":"https://doi.org/10.21926/cr.2204033","url":null,"abstract":"Solar cells based on organic-inorganic lead halide perovskites are popular in the photovoltaic community due to their high efficiency, low cost, and solution processability. Understanding the fundamentals of metal halide perovskite and its interfaces is extremely important for achieving high-quality materials and developing efficient devices using these materials with the necessary properties. Various methodologies have been used to evaluate the excellent optoelectronic properties, efficiency, and stability of PSCs. In this article, we reviewed the case studies of characterization techniques to investigate structural, optical, and electrical properties of perovskite material via electron microscopic techniques (SEM and TEM), J-V measurements, AFM, XRD, and spectroscopy techniques (PL, UV-vis, XPS, Raman, FTIR, and EIS). PSCs also need to have long-term stability and large-scale applicability for successful commercialization. In this review, we studied perovskite in detail to understand the key properties of the materials to facilitate the commercialization of PSCs.","PeriodicalId":178524,"journal":{"name":"Catalysis Research","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127991880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. Stamatis, D. Gournis, A. Polydera, Stamatia Spyrou, Konstantinos Spyrou, Elena Gkantzou, Anastasia Skonta
3D printed PLA has already been demonstrated for several biotechnological applications, including enzymes immobilization. The prerequisites for an efficient screening assay include using small volumes of reagents, low cost, and rapid screening of large numbers of compounds and extracts. Hence, assays based on microtiter plates are predominant. Thus, designing and fabricating scaffolds on a similar scale, which could serve as immobilization carriers, and their recruitment in inhibitors screening studies is of great significance, adding both enzyme stability and reuse potentiality of the biocatalytic system in assay merits. In this work, pancreatic lipase was immobilized on 3D-printed PLA microwells for enzyme inhibitor screening. XPS analysis demonstrated the successful modification of the PLA scaffolds. The immobilized enzyme displayed high levels of operational, thermal, and storage stability under the tested conditions. The IC50 values for PPL inhibition were calculated for Orlistat, a model lipase inhibitor, and olive leaf extract, a promising natural compound. This is the first study reporting the use of 3D-printed PLA wells with an immobilized enzyme for inhibitor screening assay.
{"title":"3D Printed Polylactic Acid (PLA) Well Plates for Enzyme Inhibition Studies: The Case of Pancreatic Lipase","authors":"H. Stamatis, D. Gournis, A. Polydera, Stamatia Spyrou, Konstantinos Spyrou, Elena Gkantzou, Anastasia Skonta","doi":"10.21926/cr.2203032","DOIUrl":"https://doi.org/10.21926/cr.2203032","url":null,"abstract":"3D printed PLA has already been demonstrated for several biotechnological applications, including enzymes immobilization. The prerequisites for an efficient screening assay include using small volumes of reagents, low cost, and rapid screening of large numbers of compounds and extracts. Hence, assays based on microtiter plates are predominant. Thus, designing and fabricating scaffolds on a similar scale, which could serve as immobilization carriers, and their recruitment in inhibitors screening studies is of great significance, adding both enzyme stability and reuse potentiality of the biocatalytic system in assay merits. In this work, pancreatic lipase was immobilized on 3D-printed PLA microwells for enzyme inhibitor screening. XPS analysis demonstrated the successful modification of the PLA scaffolds. The immobilized enzyme displayed high levels of operational, thermal, and storage stability under the tested conditions. The IC50 values for PPL inhibition were calculated for Orlistat, a model lipase inhibitor, and olive leaf extract, a promising natural compound. This is the first study reporting the use of 3D-printed PLA wells with an immobilized enzyme for inhibitor screening assay.","PeriodicalId":178524,"journal":{"name":"Catalysis Research","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115374758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The present study investigated the co-gasification of two different lignites blended with the forest residue collected from the land restoration activity sites of open-pit mines located in the region of the Ptolemais basin in North Greece performed under the carbon dioxide stream. All samples were devolatilized in a fixed bed unit prior to the gasification evaluations. The gasification evaluations were performed using a thermal analysis system (TG/DTG) operated at temperatures of up to 1000 °C. The reactivity, conversion, cold gas efficiency, and influence of the external catalysts CaO and K2CO3 were assessed in the evaluations. The reaction rate of the forest residue was 2–3 folds higher than that of the lignites, with the conversion of the former reaching a value of 96.4% (dry basis), while the conversion of the lignites varied between 43.4% and 51.6%. The peak inflection temperature was in the range of 859–939 °C. The reactivity of the lignite/biomass blends was higher than that of the lignites, and the final conversion was increased by approximately 30%. When individual biochars were impregnated with 30% CaO or K2CO3, the process occurred at lower temperatures, and the conversion of the lignites increased by 35%–40% while that of the forest residue reached a value of 100%. The CaO catalyst performed better. Finally, a blend of equal amounts of Kardia lignite or Ahlada lignite and the forest residue with 30% CaO was formulated, which resulted in an 89.6% or 71.7% conversion to carbon monoxide gas, respectively.
{"title":"Catalytic Co-gasification of Lignites Blended with a Forest Residue under the Carbon Dioxide Stream","authors":"D. Vamvuka, Christia Loulashi","doi":"10.21926/cr.2203031","DOIUrl":"https://doi.org/10.21926/cr.2203031","url":null,"abstract":"The present study investigated the co-gasification of two different lignites blended with the forest residue collected from the land restoration activity sites of open-pit mines located in the region of the Ptolemais basin in North Greece performed under the carbon dioxide stream. All samples were devolatilized in a fixed bed unit prior to the gasification evaluations. The gasification evaluations were performed using a thermal analysis system (TG/DTG) operated at temperatures of up to 1000 °C. The reactivity, conversion, cold gas efficiency, and influence of the external catalysts CaO and K2CO3 were assessed in the evaluations. The reaction rate of the forest residue was 2–3 folds higher than that of the lignites, with the conversion of the former reaching a value of 96.4% (dry basis), while the conversion of the lignites varied between 43.4% and 51.6%. The peak inflection temperature was in the range of 859–939 °C. The reactivity of the lignite/biomass blends was higher than that of the lignites, and the final conversion was increased by approximately 30%. When individual biochars were impregnated with 30% CaO or K2CO3, the process occurred at lower temperatures, and the conversion of the lignites increased by 35%–40% while that of the forest residue reached a value of 100%. The CaO catalyst performed better. Finally, a blend of equal amounts of Kardia lignite or Ahlada lignite and the forest residue with 30% CaO was formulated, which resulted in an 89.6% or 71.7% conversion to carbon monoxide gas, respectively.","PeriodicalId":178524,"journal":{"name":"Catalysis Research","volume":"280 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125735171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, we prepared a fine-grained, aluminum-reinforced alumina support matrix of the active mass of catalysts, which showed activity in heterogeneous catalytic reactions stimulated by electromagnetic radiation in the microwave range. The support absorbed microwave radiation of 2.45 GHz. We compared the textural characteristics of samples of Аl/Аl2О3 supports obtained by conventional heat treatment to those synthesized by heat treatment in a microwave field. We found several advantages of heat treating potential supports of the active mass by using microwave radiation. Using the examples of joint deep oxidation of n-butane and carbon monoxide, dealkylation of toluene with water vapor into benzene, and acidylation of diethyl amine with m-toluic acid, we found that after exposure to microwave radiation, the fine-grained aluminum powder-reinforced Аl/Аl2О3 support can be used for preparing catalysts that can be used in reactions stimulated by a microwave electromagnetic field.
{"title":"Effect of Microwave Radiation on the Development of a Porous Aluminum Carrier of the Active Mass of Catalysts in Heterogeneous Catalytic Reactions","authors":"P. Muradova","doi":"10.21926/cr.2203030","DOIUrl":"https://doi.org/10.21926/cr.2203030","url":null,"abstract":"In this study, we prepared a fine-grained, aluminum-reinforced alumina support matrix of the active mass of catalysts, which showed activity in heterogeneous catalytic reactions stimulated by electromagnetic radiation in the microwave range. The support absorbed microwave radiation of 2.45 GHz. We compared the textural characteristics of samples of Аl/Аl2О3 supports obtained by conventional heat treatment to those synthesized by heat treatment in a microwave field. We found several advantages of heat treating potential supports of the active mass by using microwave radiation. Using the examples of joint deep oxidation of n-butane and carbon monoxide, dealkylation of toluene with water vapor into benzene, and acidylation of diethyl amine with m-toluic acid, we found that after exposure to microwave radiation, the fine-grained aluminum powder-reinforced Аl/Аl2О3 support can be used for preparing catalysts that can be used in reactions stimulated by a microwave electromagnetic field.","PeriodicalId":178524,"journal":{"name":"Catalysis Research","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126609974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cyclodextrin glycosyltransferase (CGTase) is a multifunctional enzyme that hydrolyzes the α-glycosidic bond between two sugar molecules and synthesizes cyclodextrins (CDs) and other transglycosylation products. It is a ubiquitously present extracellular enzyme that offers the CGTase-producing organism the sole right onto starch substrates over other microbes. The present review provides a brief account of diversity among CGTase-producing microbes, CGTase production in different heterologous hosts (wherein extracellular secretion is highly desired), and different physicochemical properties of CGTases. Overall, 52 crystal structures that highlight the five domain tertiary structure of CGTases have been discovered so far. On the basis of these structures, the catalytic mechanism of CGTase reactions has been discussed, and three catalytic residues, namely Glu257, Asp229, and Asp328, have been identified at the active site in all CGTases. Moreover, the active site is constituted by at least nine sugar-binding sites, denoted as -7 to +2. Furthermore, a sequence alignment of selected CGTases highlighted the conserved regions and the sequential differences among α-CGTases, β-CGTases, and γ-CGTases. Various biotechnological applications of CGTases and CGTase immobilization on a variety of support matrices are briefly discussed. This review also encompasses a detailed account of CDs, their enzymatic production, extraction, and applications in different industrial sectors.
{"title":"Microbial Cyclodextrin Glycosyltransferases: Sources, Production, and Application in Cyclodextrin Synthesis","authors":"Rani Gupta, Arpit Tyagi, V. Pathak, K. Saini","doi":"10.21926/cr.2203029","DOIUrl":"https://doi.org/10.21926/cr.2203029","url":null,"abstract":"Cyclodextrin glycosyltransferase (CGTase) is a multifunctional enzyme that hydrolyzes the α-glycosidic bond between two sugar molecules and synthesizes cyclodextrins (CDs) and other transglycosylation products. It is a ubiquitously present extracellular enzyme that offers the CGTase-producing organism the sole right onto starch substrates over other microbes. The present review provides a brief account of diversity among CGTase-producing microbes, CGTase production in different heterologous hosts (wherein extracellular secretion is highly desired), and different physicochemical properties of CGTases. Overall, 52 crystal structures that highlight the five domain tertiary structure of CGTases have been discovered so far. On the basis of these structures, the catalytic mechanism of CGTase reactions has been discussed, and three catalytic residues, namely Glu257, Asp229, and Asp328, have been identified at the active site in all CGTases. Moreover, the active site is constituted by at least nine sugar-binding sites, denoted as -7 to +2. Furthermore, a sequence alignment of selected CGTases highlighted the conserved regions and the sequential differences among α-CGTases, β-CGTases, and γ-CGTases. Various biotechnological applications of CGTases and CGTase immobilization on a variety of support matrices are briefly discussed. This review also encompasses a detailed account of CDs, their enzymatic production, extraction, and applications in different industrial sectors.","PeriodicalId":178524,"journal":{"name":"Catalysis Research","volume":"251 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133786703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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