Reactions最新文献_第6页

Immobilization of Cellulolytic Enzymes in Accurel® MP1000 纤维素水解酶在Accurel®MP1000中的固定化

Reactions Pub Date : 2023-06-16 DOI: 10.3390/reactions4020019

Júlia Baruque, Adriano Carniel, J. C. S. Sales, B. Ribeiro, Rodrigo P. do Nascimento, Ivaldo Itabaiana

{"title":"Immobilization of Cellulolytic Enzymes in Accurel® MP1000","authors":"Júlia Baruque, Adriano Carniel, J. C. S. Sales, B. Ribeiro, Rodrigo P. do Nascimento, Ivaldo Itabaiana","doi":"10.3390/reactions4020019","DOIUrl":"https://doi.org/10.3390/reactions4020019","url":null,"abstract":"Cellulases are a class of enzymes of great industrial interest that present several strategic applications. However, the high cost of enzyme production, coupled with the instabilities and complexities of proteins required for hydrolytic processes, still limits their use in several protocols. Therefore, enzyme immobilization may be an essential tool to overcome these issues. The present work aimed to evaluate the immobilization of cellulolytic enzymes of the commercial enzyme cocktail Celluclast® 1.5 L in comparison to the cellulolytic enzyme cocktail produced from the wild strain Trichoderma harzianum I14-12 in Accurel® MP1000. Among the variables studied were temperature at 40 °C, ionic strength of 50 mM, and 72 h of immobilization, with 15 m·L −1 of proteins generated biocatalysts with high immobilization efficiencies (87% for ACC-Celluclast biocatalyst and 95% for ACC-ThI1412 biocatalyst), high retention of activity, and specific activities in the support for CMCase (DNS method), FPase (filter paper method) and β-glucosidase (p-nitrophenyl-β-D-glucopyranoside method). Presenting a lower protein concentration (0.32 m·L−1) than the commercial Celluclast® 1.5 L preparation (45 m·L−1), the ACC-ThI1412-derived immobilized biocatalyst showed thermal stability at temperatures higher than 60 °C, maintaining more than 90% of the residual activities of FPase, CMCase, and β-glucosidase. In contrast, the commercial-free enzyme presented a maximum catalytic activity at only 40 °C. Moreover, the difference in molecular weight between the component enzymes of the extract was responsible for different hydrophobic and lodging interactions of proteins on the support, generating a robust and competitive biocatalyst.","PeriodicalId":20873,"journal":{"name":"Reactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82825361","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}

引用次数: 0

Biofuels from Pyrolysis of Third-Generation Biomass from Household and Garden Waste Composting Bin: Kinetics Analysis 从家庭和花园垃圾堆肥箱中热解第三代生物质制备生物燃料:动力学分析

Reactions Pub Date : 2023-06-12 DOI: 10.3390/reactions4020018

Bruna Rijo, A. P. Soares Dias, Novi Dwi Saksiwi, M. Pereira, R. Zăvoianu, O. Pavel, O. Ferreira, R. G. dos Santos

{"title":"Biofuels from Pyrolysis of Third-Generation Biomass from Household and Garden Waste Composting Bin: Kinetics Analysis","authors":"Bruna Rijo, A. P. Soares Dias, Novi Dwi Saksiwi, M. Pereira, R. Zăvoianu, O. Pavel, O. Ferreira, R. G. dos Santos","doi":"10.3390/reactions4020018","DOIUrl":"https://doi.org/10.3390/reactions4020018","url":null,"abstract":"The modern society produces large amounts of household waste with high organic matter content. The vermicomposting of household waste produces high-value humic substances and is a way to stabilize organic material for later use as raw material (3rd generation biomass) for bioenergy proposes. A 6-month matured compost, combining vegetable and fruit scraps from domestic trash and grass and shrub clippings from yard waste, was evaluated to assess its potential as a raw material in pyrolysis processes. The pyrolysis activation energy (Kissinger) of the composted material showed values in the range of 200–300 kJ/mol, thus confirming its suitability for pyrolysis processes with promising H2 yields. The treatment of the composted material with H2SO4 and NaOH solution (boiling; 1 mol/L) led to the production of solid residues that present higher pyrolysis activation energies, reaching 550 kJ/mol for the most resilient fraction, which makes them suitable to produce carbonaceous materials (biochar) that will have incorporated the inorganics existing in the original compost (ashes 37.6%). The high content of inorganics would play a chief role during pyrolysis since they act as gasification promoters.","PeriodicalId":20873,"journal":{"name":"Reactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88247126","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}

引用次数: 0

Amoxicillin/clavulanic acid 阿莫西林/克拉维酸

Reactions Pub Date : 2023-06-01 DOI: 10.1007/s40278-023-40234-2

引用次数: 0

N-Aryl Amino Acids as Potential Antibacterial Agents n -芳基氨基酸作为潜在的抗菌剂

Reactions Pub Date : 2023-05-31 DOI: 10.3390/reactions4020017

A. Osinubi, O. Asekun, OLUWOLE Babafemi Familoni

{"title":"N-Aryl Amino Acids as Potential Antibacterial Agents","authors":"A. Osinubi, O. Asekun, OLUWOLE Babafemi Familoni","doi":"10.3390/reactions4020017","DOIUrl":"https://doi.org/10.3390/reactions4020017","url":null,"abstract":"The resistance of bacteria to current antibiotic drugs and the re-occurrence of different ailments after several therapeutic protocols continue to be a cause for concern. Arylated amino acids are vital synthons to many compounds; they serve as essential building blocks in the synthesis of nitrogen heterocycles with various biological activities. This research reports on the synthesis of some N-aryl amino acids and evaluates their antibacterial activities. The N-aryl amino acids 3a–3j were obtained by reacting different 4-substituted fluorobenzene 1a–1d with different amino acids 2a–2g via a metal-free base-induced aryl amination reaction of aryl halides. The antibacterial activities of the synthesized compounds were evaluated against eight bacterial strains (Four Gram-positive, Bacillus subtilis (ATCC 6633), Streptococcus pneumonia (ATCC 33400), Staphylococcus aureus (ATCC 25923), and Staphylococcus epidermidis (ATCC 14990), and four Gram-negative, Enterobacter cloacae (ATCC 43560), Escherichia coli (ATCC 25922), Proteus mirabilis (ATCC 43071), and Klebsiella oxytoca (ATCC 13182) using the agar well diffusion method with streptomycin as a reference drug. The biological screening indicates that the synthesized compounds 3a, 3e, and 3j have promising broad-spectrum antibacterial potential, as the N-aryl amino acid displayed activity that was comparable to the standard drug against Streptococcus pneumonia, Escherichia coli, and Proteus mirabilis.","PeriodicalId":20873,"journal":{"name":"Reactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91170710","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}

引用次数: 0

The First Step and the Cob(II)alamin Cofactor Inactive Particles Reactivation in the Updated Mechanism of the Methionine Synthase Process 蛋氨酸合酶过程的第一步和Cob(II)alamin辅因子失活颗粒再激活的最新机制

Reactions Pub Date : 2023-05-22 DOI: 10.3390/reactions4020016

T. Spataru

{"title":"The First Step and the Cob(II)alamin Cofactor Inactive Particles Reactivation in the Updated Mechanism of the Methionine Synthase Process","authors":"T. Spataru","doi":"10.3390/reactions4020016","DOIUrl":"https://doi.org/10.3390/reactions4020016","url":null,"abstract":"The Methionine Synthase process, in principle, can take an unlimited number of turnovers in the presence of the AdoMet substrate. In the absence of this substrate, the Methionine Synthase process lasts only about 2000 turnovers. During 2000 turnovers, the entire amount of methylcob(II)alamin cofactor is converted into inactive cob(II)alamin particles. Nevertheless, the mechanism of the Methionine Synthase process determined previously lacks the presence of the AdoMet substrate. On the other hand, the first step of this mechanism was only mentioned earlier without its analysis. The CASSCF geometry optimization of the inactive cob(II)alamin cofactor particle plus the AdoMet ion substrate and of the methylcob(II)alamin cofactor particle plus homocysteine ion and histidine molecule joint models have been performed. CASSCF calculations show that the AdoMet particle transfers the methyl radical to the biologically inactive cob(II)alamin particle during their interaction, transforming it into the biologically active particle of methylcob(II)alamin. CASSCF geometry optimization of the second model leads to the Co-N bond’s full cleavage. The two processes take place in the absence of the total energy barrier. The fully updated mechanism of the Methionine Synthase process has been drawn.","PeriodicalId":20873,"journal":{"name":"Reactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79066638","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}

引用次数: 0

Hemetsberger–Knittel and Ketcham Synthesis of Heteropentalenes with Two (1:1), Three (1:2)/(2:1) and Four (2:2) Heteroatoms 二(1:1)、三(1:2)/(2:1)和四(2:2)杂原子杂戊烯的Hemetsberger-Knittel和Ketcham合成

Reactions Pub Date : 2023-05-08 DOI: 10.3390/reactions4020015

Z. Tokárová, R. Gašparová, Natalia M. Kabanova, Marcela Gašparová, R. Balogh

{"title":"Hemetsberger–Knittel and Ketcham Synthesis of Heteropentalenes with Two (1:1), Three (1:2)/(2:1) and Four (2:2) Heteroatoms","authors":"Z. Tokárová, R. Gašparová, Natalia M. Kabanova, Marcela Gašparová, R. Balogh","doi":"10.3390/reactions4020015","DOIUrl":"https://doi.org/10.3390/reactions4020015","url":null,"abstract":"The synthetic methods leading to furo[3,2-b]pyrroles and thiazolo [5,4-d]thiazoles are reviewed herein. Furo-, thieno- and seleno [3,2-b]pyrroles are related to heteropentalenes, containing two heteroatoms in the entire structure, one each per core. The synthetic approach follows the Hemetsberger–Knittel protocol covering three reaction steps—the nucleophilic substitution of halogen-containing aliphatic carboxylic acid esters, Knoevenagel condensation and, finally, thermolysis promoting the intramolecular cyclocondensation to O,N-heteropentalene. The Hemetsberger–Knittel reaction sequence is also known for the preparation of O,N-heteropentalenes with three heteroatoms (2:1) and their sulphur and selen heteroatoms containing structural analogues and bispyrroles. The synthetic approach towards thiazolo [5,4-d] thiazoles represents a more straightforward route, according to the Ketcham cyclocondensation. Proceeding with the Ketcham process is more challenging since it occurs stepwise and the formation of by-products is obvious. Thiazolo [5,4-d]thiazole is a representative of the aromatic heteropentalene with four heteroatoms in the structure—twinned N and S, two for each of the five-membered rings. The synthetic approaches towards those particular heteropentalnes have been chosen as a consequence of our ongoing research dealing with the design, synthesis and applications of substituted furo [3,2-b]pyrroles and thiazolo [5,4-d]thiazole-based derivatives. While the furopyrroles are known for their pharmacological activity, thiazolothiazoles have become of interest to materials science. We are aware that from a “bank” of existing compounds/procedures not all are presented in this review, and we apologise to respective groups whose research have not been objectively included.","PeriodicalId":20873,"journal":{"name":"Reactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85586427","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}

引用次数: 0

Enhancing Photon Transfer Efficiency in Photocatalysis Using Suspended LED Lights for Water Treatment 利用悬浮式LED灯提高光催化中的光子传递效率

Reactions Pub Date : 2023-04-18 DOI: 10.3390/reactions4020014

Samira Mosalaei Rad, A. Ray, S. Barghi

{"title":"Enhancing Photon Transfer Efficiency in Photocatalysis Using Suspended LED Lights for Water Treatment","authors":"Samira Mosalaei Rad, A. Ray, S. Barghi","doi":"10.3390/reactions4020014","DOIUrl":"https://doi.org/10.3390/reactions4020014","url":null,"abstract":"Photocatalysis application in water treatment has been the object of many researchers worldwide in recent decades. However, there are limited commercial applications due to low photon transfer efficiency, which create barriers leading to challenges in making the process efficient and economically feasible. Fixed UV/visible light sources, which are generally located outside the reactor or encapsulated in quartz tube inside the reactor are the source of energy to activate photocatalyst generating powerful oxidants such as electrons and holes. Suspended waterproof LED visible lights were employed to enhance photon transfer efficiency. Consequently, the required energy was lower resulting in negligible temperature increase and eliminated the need for an external cooler, no need for quartz (UV transparent) or treated glass reactors, enhanced mixing due to continuous movement of light bulbs by convective currents, and minimum/no attenuation. Direct Blue 15 (DB15) dye was used as model compound and the photocatalyst was P25 TiO2 (Average particle: 30 nm, Surface area: 50 m2 g−1). The samples taken at different time intervals were analyzed by UV-Vis. spectrophotometer (UV-3600), and TOC-V CPN total organic carbon analyzer (both from Shimadzu). It was found that for the same level of degradation, the degradation rate increased by about 50% compared to conventional fixed light photoreactor. Overall, the cost of the operation can be reduced substantially, paving the road for feasible commercialization of the process.","PeriodicalId":20873,"journal":{"name":"Reactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76548294","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}

引用次数: 0

Biocatalytic Profiling of Free and Immobilized Partially Purified Alkaline Protease from an Autochthonous Bacillus aryabhattai Ab15-ES 原生芽孢杆菌Ab15-ES游离和固定化部分纯化碱性蛋白酶的生物催化分析

Reactions Pub Date : 2023-04-03 DOI: 10.3390/reactions4020013

Adegoke Isiaka Adetunji, A. Olaniran

{"title":"Biocatalytic Profiling of Free and Immobilized Partially Purified Alkaline Protease from an Autochthonous Bacillus aryabhattai Ab15-ES","authors":"Adegoke Isiaka Adetunji, A. Olaniran","doi":"10.3390/reactions4020013","DOIUrl":"https://doi.org/10.3390/reactions4020013","url":null,"abstract":"Partially purified alkaline protease produced by an indigenous bacterial strain, Bacillus aryabhattai Ab15-ES, was insolubilized in alginate beads using an entrapment technique. Maximum entrapped enzyme activities of 68.76% and 71.06% were recorded at optimum conditions of 2% (w/v) sodium alginate and 0.3 M calcium chloride. Biochemical profiling of free and immobilized proteases was investigated by determining their activity and stability as well as kinetic properties. Both enzyme preparations exhibited maximum activity at the optimum pH and temperature of 8.0 and 50 °C, respectively. However, in comparison to the free enzyme, the immobilized protease showed improved pH stability at 8.0–9.0 and thermal stability at 40–50 °C. In addition, the entrapped protease exhibited a higher Vmax and increased affinity to the substrate (1.65-fold) than the soluble enzyme. The immobilized protease was found to be more stable than the free enzyme, retaining 80.88% and 38.37% of its initial activity when stored at 4 °C and 25 °C, respectively, for 30 d. After repeated use seven times, the protease entrapped in alginate beads maintained 32.93% of its original activity. These findings suggest the efficacy and sustainability of the developed immobilized catalytic system for various biotechnological applications.","PeriodicalId":20873,"journal":{"name":"Reactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78865798","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}

引用次数: 2

BCG vaccine 卡介苗

Reactions Pub Date : 2023-04-01 DOI: 10.1007/s40278-023-37930-x

引用次数: 0

Visible Light Induced C-H/N-H and C-X Bonds Reactions 可见光诱导的C-H/N-H和C-X键反应

Reactions Pub Date : 2023-03-02 DOI: 10.3390/reactions4010012

M. Ahmad, Po-han Lin, Qing Zhang, Bing Zeng, Qifeng Wang, K. Meguellati

引用次数: 0