Frontiers in catalysis最新文献_第5页

Alcohol Dehydrogenases as Catalysts in Organic Synthesis 醇脱氢酶在有机合成中的催化作用

Frontiers in catalysis Pub Date : 2022-05-10 DOI: 10.3389/fctls.2022.900554

A. S. de Miranda, C. D. Milagre, F. Hollmann

引用次数: 13

Hydrophobic Outer Membrane Pores Boost Testosterone Hydroxylation by Cytochrome P450 BM3 Containing Cells 疏水性外膜孔促进含细胞色素P450 BM3细胞的睾酮羟基化

Frontiers in catalysis Pub Date : 2022-04-26 DOI: 10.3389/fctls.2022.887458

Carolin Bertelmann, M. Mock, R. Koch, A. Schmid, B. Bühler

{"title":"Hydrophobic Outer Membrane Pores Boost Testosterone Hydroxylation by Cytochrome P450 BM3 Containing Cells","authors":"Carolin Bertelmann, M. Mock, R. Koch, A. Schmid, B. Bühler","doi":"10.3389/fctls.2022.887458","DOIUrl":"https://doi.org/10.3389/fctls.2022.887458","url":null,"abstract":"The implementation of biocatalytic steroid hydroxylation processes at an industrial scale still suffers from low conversion rates. In this study, we selected variants of the self-sufficient cytochrome P450 monooxygenase BM3 from Bacillus megaterium (BM3) for the hydroxylation of testosterone either at the 2β- or 15β-position. Recombinant Escherichia coli cells were used as biocatalysts to provide a protective environment for recombinant enzymes and to ensure continuous cofactor recycling via glucose catabolism. However, only low initial whole-cell testosterone conversion rates were observed for resting cells. Results obtained with different biocatalyst formats (permeabilized cells, cell-free extracts, whole cells) indicated a limitation in substrate uptake, most likely due to the hydrophilic character of the outer membrane of E. coli. Thus, we co-expressed nine genes encoding hydrophobic outer membrane proteins potentially facilitating steroid uptake. Indeed, the application of four candidates led to increased initial testosterone hydroxylation rates. Respective whole-cell biocatalysts even exceeded activities obtained with permeabilized cells or cell-free extracts. The highest activity of 34 U gCDW −1 was obtained for a strain containing the hydrophobic outer membrane protein AlkL from Pseudomonas putida GPo1 and the BM3 variant KSA14m. Overall, we show that the straightforward application of hydrophobic outer membrane pores can boost whole-cell steroid conversion rates and thus be game-changing with regard to industrial steroid production efficiency.","PeriodicalId":73071,"journal":{"name":"Frontiers in catalysis","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45188223","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: 1

Colorimetric High-Throughput Screening Assay to Engineer Fungal Peroxygenases for the Degradation of Thermoset Composite Epoxy Resins 工程菌过氧化物酶降解热固性复合环氧树脂的比色高通量筛选

Frontiers in catalysis Pub Date : 2022-04-08 DOI: 10.3389/fctls.2022.883263

M. Dolz, Ivan Mateljak, D. Méndez-Sánchez, Israel Sánchez-Moreno, Patricia Gomez de Santos, Javier Viña‐Gonzalez, M. Alcalde

{"title":"Colorimetric High-Throughput Screening Assay to Engineer Fungal Peroxygenases for the Degradation of Thermoset Composite Epoxy Resins","authors":"M. Dolz, Ivan Mateljak, D. Méndez-Sánchez, Israel Sánchez-Moreno, Patricia Gomez de Santos, Javier Viña‐Gonzalez, M. Alcalde","doi":"10.3389/fctls.2022.883263","DOIUrl":"https://doi.org/10.3389/fctls.2022.883263","url":null,"abstract":"At present, the end-of-life management of thermoset composite epoxy resins is limited to incineration and landfill storage, highlighting the demand for the development of more sustainable measures. Due to their broad spectrum of C-H oxyfunctionalization reactions, fungal unspecific peroxygenases (UPOs) are becoming important biotechnological tools in organic synthesis while their potential use in biodegradation processes should not be underestimated. Here, we present a colorimetric screening assay aimed at engineering UPOs for the degradation of epoxy resins. We based our study on Hexflow® RTM-6, a commercial epoxy resin used extensively in the aeronautics sector. UPO mutants from the short and long families were initially benchmarked by GC/MS to determine their potential N-dealkylation activity on N,N-bis(2-hydroxypropyl)-p-toluidine (NNBT), the main structural scaffold of Hexflow® RTM-6. A reliable high-throughput colorimetric screening method was developed to quantify the lactaldehyde released by UPO attack on the tertiary amine of NNBT. Based on an evolved UPO from Psathyrella aberdarensis that was expressed by yeast, a small subset of mutant libraries with different mutational loadings was constructed and screened for NNBT N-dealkylation, thereby establishing a directed evolution platform as a vehicle to engineer UPO composite degrading variants.","PeriodicalId":73071,"journal":{"name":"Frontiers in catalysis","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47125898","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

A Review on Bismuth Oxyhalide (BiOX, X=Cl, Br, I) Based Photocatalysts for Wastewater Remediation 卤氧化铋（BiOX，X=Cl，Br，I）基废水修复光催化剂研究进展

Frontiers in catalysis Pub Date : 2022-04-06 DOI: 10.3389/fctls.2022.839072

Xincong Lv, F. L. Lam, Xijun Hu

引用次数: 11

Nonmetallic Mineral as the Carrier of TiO2 Photocatalyst: A Review 非金属矿物作为TiO2光催化剂载体的研究进展

Frontiers in catalysis Pub Date : 2022-03-30 DOI: 10.3389/fctls.2022.806316

Yanlong Xie, Jiao Wang, Fengguo Ren, H. Shuai, G. Du

引用次数: 1

Process Intensification as Game Changer in Enzyme Catalysis 过程强化是酶催化的游戏规则改变者

Frontiers in catalysis Pub Date : 2022-03-21 DOI: 10.3389/fctls.2022.858706

Bastien O. Burek, A. Dawood, F. Hollmann, A. Liese, D. Holtmann

{"title":"Process Intensification as Game Changer in Enzyme Catalysis","authors":"Bastien O. Burek, A. Dawood, F. Hollmann, A. Liese, D. Holtmann","doi":"10.3389/fctls.2022.858706","DOIUrl":"https://doi.org/10.3389/fctls.2022.858706","url":null,"abstract":"Enzyme catalysis, made tremendous progress over the last years in identification of new enzymes and new enzymatic reactivity’s as well as optimization of existing enzymes. However, the performance of the resulting processes is often still limited, e.g., in regard of productivity, realized product concentrations and the stability of the enzymes. Different topics (like limited specific activity, unfavourable kinetics or limited enzyme stability) can be addressed via enzyme engineering. On the other hand, there is also a long list of topics that are not addressable by enzyme engineering. Here typical examples are unfavourable reaction thermodynamics, selectivity in multistep reactions or low water solubility. These challenges can only be addressed through an adaption of the reaction system. The procedures of process intensification (PI) represent a good approach to reach most suitable systems. The general objective of PI is to achieve significant benefits in terms of capital and operating costs as well as product quality, waste, and process safety by applying innovative principles. The aim of the review is to show the current capabilities and future potentials of PI in enzyme catalysis focused on enzymes of the class of oxidoreductases. The focus of the paper is on alternative methods of energy input, innovative reactor concepts and reaction media with improved properties.","PeriodicalId":73071,"journal":{"name":"Frontiers in catalysis","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49006668","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: 17

Photo-Regulation of Enzyme Activity: The Inactivation of a Carboligase with Genetically Encoded Photosensitizer Fusion Tags 酶活性的光调控:用基因编码的光敏剂融合标签使碳糖酶失活

Frontiers in catalysis Pub Date : 2022-03-16 DOI: 10.3389/fctls.2022.835919

T. Gerlach, Jendrik Schain, Simone Söltl, Morten M. C. H. van Schie, F. Hilgers, N. Bitzenhofer, T. Drepper, D. Rother

{"title":"Photo-Regulation of Enzyme Activity: The Inactivation of a Carboligase with Genetically Encoded Photosensitizer Fusion Tags","authors":"T. Gerlach, Jendrik Schain, Simone Söltl, Morten M. C. H. van Schie, F. Hilgers, N. Bitzenhofer, T. Drepper, D. Rother","doi":"10.3389/fctls.2022.835919","DOIUrl":"https://doi.org/10.3389/fctls.2022.835919","url":null,"abstract":"Genetically encoded photosensitizers are able to produce reactive oxygen species upon illumination and are exploited in a wide range of applications, especially in the medical field. In this work, we envisioned to further apply these genetically encoded photosensitizers for the light-dependent control of single enzymes in multi-step biocatalysis. One of the challenges in the application of several enzymes in a cascade is the unwanted cross-reactivity of these biocatalysts on reaction intermediates when all enzymes are simultaneously present in the reaction. As one strategy to address this issue, we investigated whether the introduction of genetically encoded photosensitizers as fusion tags would allow the selective inactivation of enzymes after successful transformation by simply turning on light. We tested five different photosensitizers as molecular biological fusion tags to inactivate the pyruvate decarboxylase variant E469G/W543H from Acetobacter pasteurianus. Dimeric photosensitizer tags, like the flavin-binding fluorescent proteins from Bacillus subtilis and Pseudomonas putida showed the tendency to form insoluble protein aggregates in combination with the tetrameric carboligase. Enzyme activity was, to some extent, retained in these aggregates, but the handling of the insoluble aggregates proved to be unfeasible. Monomeric photosensitizer tags appeared to be much more suitable when fused to the tetrameric enzyme. In the dark, the singlet oxygen photosensitizing protein (SOPP3)-tagged carboligase retained 79% of its activity as compared to the unfused enzyme. Upon blue light exposure, the SOPP3 tag showed the best specific inactivation and enabled complete inactivation of the carboligase within 30 min. SOPP3 is thus seen as a promising photosensitizer tag to be applied in future multi-step enzyme cascades to overcome the challenge of cross-reactivity.","PeriodicalId":73071,"journal":{"name":"Frontiers in catalysis","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47633291","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

Challenges and Opportunities for the Large-Scale Chemoenzymatic Glycoengineering of Therapeutic N-Glycosylated Monoclonal Antibodies 治疗性N-糖基化单克隆抗体大规模化酶糖工程的挑战与机遇

Frontiers in catalysis Pub Date : 2022-02-03 DOI: 10.3389/fctls.2021.810779

A. Ivanova, F. Falcioni

引用次数: 0

Effect of Graphite Oxide on the Catalytic Behavior of (S)-Selective Amine Transaminases 氧化石墨对（S）-选择性胺转氨酶催化行为的影响

Frontiers in catalysis Pub Date : 2022-02-01 DOI: 10.3389/fctls.2021.803850

Nikolaos Kaloudis, P. Zygouri, Nikolaos Chalmpes, Konstantinos Spyrou, D. Gournis, Ioannis V. Pavlidis

{"title":"Effect of Graphite Oxide on the Catalytic Behavior of (S)-Selective Amine Transaminases","authors":"Nikolaos Kaloudis, P. Zygouri, Nikolaos Chalmpes, Konstantinos Spyrou, D. Gournis, Ioannis V. Pavlidis","doi":"10.3389/fctls.2021.803850","DOIUrl":"https://doi.org/10.3389/fctls.2021.803850","url":null,"abstract":"Graphite oxide (GO) has been used for the immobilization of several classes of enzymes, exhibiting very interesting properties as an immobilization matrix. However, the effect the nanomaterial has on the enzyme cannot be predicted. Herein, the effect GO has on the catalytic behavior of several (S)-selective amine transaminases [(S)-ATAs] has been investigated. These enzymes were the focus of this work as they are homodimers with pyridoxal 5′-phosphate in their active site, significantly more complex systems than other enzymes previously studied. Addition of GO (up to 0.1 mg/ml) in the reaction medium leads to activation (up to 50% improved activity) for most enzymes studied, while they maintain their temperature profile (they perform better between 40 and 45°C) and their stability. However, the effect is not universal and there are enzymes that are negatively influenced by the presence of the nanomaterial. More profound is the effect on the (S)-ATA from Chromobacterium violaceum which loses almost 50% of its activity in the presence of 0.1 mg/ml GO, while the stability was significantly decreased, losing its activity after 2 h incubation at 40°C, in the presence of 25 μg/ml GO. This negative effect seems to rise from minor secondary structure alterations; namely, a loss of α-helices and subsequent increase in random coil (∼3% in the presence of 25 μg/ml GO). We hypothesize that the effect the GO has on (S)-ATAs is correlated to the surface chemistry of the enzymes; the less negatively-charged enzymes are deactivated from the interaction with GO. This insight will aid the rationalization of ATA immobilization onto carbon-based nanomaterials.","PeriodicalId":73071,"journal":{"name":"Frontiers in catalysis","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42929644","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

Maximizing Photosynthesis-Driven Baeyer–Villiger Oxidation Efficiency in Recombinant Synechocystis sp. PCC6803 重组胞囊藻PCC6803光合作用驱动Baeyer-Villiger氧化效率的最大化

Frontiers in catalysis Pub Date : 2022-01-21 DOI: 10.3389/fctls.2021.780474

A. Tüllinghoff, Magdalena B. Uhl, Friederike E H Nintzel, A. Schmid, B. Bühler, J. Toepel

{"title":"Maximizing Photosynthesis-Driven Baeyer–Villiger Oxidation Efficiency in Recombinant Synechocystis sp. PCC6803","authors":"A. Tüllinghoff, Magdalena B. Uhl, Friederike E H Nintzel, A. Schmid, B. Bühler, J. Toepel","doi":"10.3389/fctls.2021.780474","DOIUrl":"https://doi.org/10.3389/fctls.2021.780474","url":null,"abstract":"Photosynthesis-driven whole-cell biocatalysis has great potential to contribute to a sustainable bio-economy since phototrophic cells use light as the only energy source. It has yet to be shown that phototrophic microorganisms, such as cyanobacteria, can combine the supply of high heterologous enzyme levels with allocation of sufficient reduction equivalents to enable efficient light-driven redox biocatalysis. Here, we demonstrated that the heterologous expression of an NADPH-dependent Baeyer–Villiger monooxygenase (BVMO) gene from Acidovorax sp. CHX100 turns Synechocystis sp. PCC6803 into an efficient oxyfunctionalization biocatalyst, deriving electrons and O2 from photosynthetic water oxidation. Several expression systems were systematically tested, and a PnrsB-(Ni2+)–controlled expression based on a replicative plasmid yielded the highest intracellular enzyme concentration and activities of up to 60.9 ± 1.0 U gCDW −1. Detailed analysis of reaction parameters, side reactions, and biocatalyst durability revealed—on the one hand—a high in vivo BVMO activity in the range of 6 ± 2 U mgBVMO −1 and—on the other hand—an impairment of biocatalyst performance by product toxicity and by-product inhibition. Scale-up of the reaction to 2-L fed-batch photo-bioreactors resulted in the stabilization of the bioconversion over several hours with a maximal specific activity of 30.0 ± 0.3 U g CDW −1, a maximal volumetric productivity of 0.21 ± 0.1 gL−1 h−1, and the formation of 1.3 ± 0.1 gL−1 of ε-caprolactone. Process simulations based on determined kinetic data revealed that photosynthesis-driven cyclohexanone oxidation on a 2-L scale under high-light conditions was kinetically controlled and not subject to a limitation by photosynthesis.","PeriodicalId":73071,"journal":{"name":"Frontiers in catalysis","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42914862","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: 11