232 research outputs found
Transaminase-catalyzed continous synthesis of biogenic aldehydes
No full textThe physiological role of biogenic aldehydes such as DOPAL has been associated with cardiovascular and neurodegenerative disorders. The availability of these substrates is limited and robust synthetic methodologies would greatly facilitate further biological studies. Here we report on transaminase mediated single-step process in continuous mode which leads to excellent product yields (90-95%). Co-immoblization of the PLP cofactor eliminated the need of exogenous addition of this reagent without affecting the longevity of the system, delivering a truly self-sufficient process
Microreattori e biocatalisi: come minimizzare il divario tra ricerca accademica e industria
No full textNegli ultimi due decenni, la tecnologia dei microreattori ha cambiato il paradigma nella sintesi organica sia su scala di laboratorio che di produzione e sta recentemente ricevendo sempre maggiore attenzione anche nel campo della biocatalisi. Grazie ai vantaggi dei microreattori, quali il rapido e accurato trasferimento di massa e di calore, i piccoli volumi di reazione e i brevi percorsi di diffusione, è possibile selezionare in modo più rapido ed economico i substrati e le condizioni di reazione e sviluppare dei metodi di immobilizzazione adeguati per l’uso di biocatalizzatori in continuo. Inoltre, la progettazione di processi biocatalizzati in continuo integrati con sistemi di analisi e purificazione consente anche di scalare le biotrasformazioni in modo più efficiente e riproducibile. Nel complesso, queste caratteristiche possono colmare il divario tra la ricerca accademica e l’uso su larga scala dei biocatalizzatori.In the last two decades, microreactor technology has changed the paradigm in the laboratory and production scale organic synthesis, and is recently receiving increased attention also in the field of biocatalysis. The benefits of microflow devices, such as rapid mass and heat transfer, small reaction volumes and short diffusion pathways, results in faster and cheaper selection of substrates and media, and in the rapid development of suitable immobilization methods for continuous biocatalyst use. Furthermore, the use of highly efficient reactor designs integrated with in-line analysis and purification procedures enables faster and more reliable scale-up of biocatalysed reactions. Overall, these feature can bridge the gap between the academic research and industrial use of biocatalysts
Mycobacterium smegmatis acyltransferase: The big new player in biocatalysis
No full textAfter several decades during which proteases and after lipases took the biotransformation world scene as the predominant biocatalysts, a new, promising enzyme was discovered and characterized. The acyltransferase from Mycobacterium smegmatis (MsAcT) has in fact an extraordinary activity for a wide array of reactions, such as trans-esterification, amidation, trans-amidation and perhydrolysis, both in water and solvent media, giving rise to a series of interesting compounds including APIs (i.e., active pharmaceutical ingredients), natural flavors and fragrances, monomers for polymer synthesis, and peracids employed as disinfectants or antimicrobials. Although the most used acylating agent has been ethyl acetate (EtOAc), depending on the reaction type also acetamide, dimethyl carbonate and a variety of other esters, have been reported. The best yields were reached using very reactive donors such as vinyl or isopropenyl esters (almost complete conversion in rapid reaction times and water media for condensation reactions). In this review article the most innovative scientific advances on MsAcT, its mechanism and engineering are summarized, putting a particular focus on the different kind of processes (batch and flow) that it is possible to carry out using this enzyme as free or immobilized form. In conclusion, the author personal view on the unexplored reaction possibilities using MsAcT is reported as a window on the future of the topic
When biocatalysis meets flow chemistry
No full textThe number of biocatalyzed reactions in the industrial context is growing rapidly together with our understanding on how we can maximize the enzyme productivity increasing catalyst efficiency and stability. Although biocatalysis is nowadays identified as a greener way to operate in chemistry, its incorporation in flow reactors has lately come up as a powerful tool to enhance process productivity, sustainability and selectivity. This opinion article aims at describing the recent advances of this technology and future developments allowing for efficient, smart and environmentally-friendly strategies for process optimization and large scale production
Stereoselective monoreduction of bulky 1,2-dicarbonyls catalyzed by a benzyl reductase from Pichia glucozyma (KRED1-Pglu)
No full textEnantiomerically enriched hydroxyketones are well-established intermediates for the synthesis of several bioactive compounds [1] and can be chemically obtained by stereoselective reduction of one of the carbonyl moieties of the corresponding diketones. However, enzymatic strategies are characterized by higher catalytic efficiency, milder reaction conditions, higher stereo- and regioselectivity, and fewer numbers of synthetic steps. Therefore, they can be chosen as convenient and environmentally friendly alternatives.[2]
A NADPH-dependent benzyl reductase from the non-conventional yeast Pichia glucozyma (KRED1-Pglu [3]) was over-expressed in E. coli, purified and exploited to catalyze the asymmetric monoreduction of bulky aromatic 1,2-dicarbonyl compounds. The cofactor was recycled by an enzyme-coupled system (glucose-glucose dehydrogenase (GDH) from Bacillus megaterium). The recombinant KRED1-Pglu showed a wide range of activity (24-97% conversion) and excellent stereoselectivity (ee ≥ 96% in all but one case). On the contrary, it proved either inactive or very poorly active towards most 1,3- and 1,4-dicarbonyls tested as potential substrates. In order to understand this peculiar behavior, the enzyme was crystallized (1.77 Å resolution) and its active site was investigated to identify the recognition residues involved in the desymmetrization reaction. QM and classical calculations also allowed for a proposal of the catalytic mechanism, along with an in silico reactivity prediction.[4]
[1] G. Aullón; P. Romea; F. Urpí Synthesis, 2017, 49, 484-503.
[2] P. Hoyos; J.-V. Sinisterra; F. Molinari; A.R. Alántara; P. Domínguez de María Acc. Chem. Res., 2010, 43, 288-299.
[3] M.L. Contente; I. Serra; M. Brambilla; I. Eberini; E. Giannazza; V. De Vitis; F. Molinari; P. Zambelli; D. Romano Appl. Microbiol. Biotechnol., 2016, 100, 193-201.
[4] M. Rabuffetti; P. Cannazza; M.L. Contente; A. Pinto; D. Romano; P. Hoyos; A.R. Alcántara; I. Eberini; T. Laurenzi; L. Gourlay; F. Di Pisa; F. Molinari Bioorg. Chem., 2021, 108, 104644
Aromas flow: eco-friendly, continuous, and scalable preparation of flavour esters
No full textFlow-based biocatalysis offers advantages to perform multiphase reactions, including liquid–liquid reactions, due to intensified mass transfer, compartmentalization and high local concentration of the catalyst. Enzymatic immobilization leads to stable biocatalysts, with the possibility to incorporate them in continuous reactors. The combination between the two technologies allows for intensified process with high substrate concentration and high product recovery. The present paper is an excellent example of automated continuous biocatalytic process where a transferase from Mycobacterium smegmatis (MsAcT) was immobilized onto agarose beads and exploited for the preparation of a variety of flavour-esters, utilizing exclusively natural substrates, with excellent yields in 5-min reaction times. The corresponding products can be labelled and commercialized as natural too, thus increasing their market value
Advances on whole-cell biocatalysis in flow
No full textThe combination of enabling technologies, such as biocatalysis and flow chemistry, represents an important opportunity to expand the chemical toolbox for the preparation of fine chemicals and pharmaceuticals under ambient and environmentally benign conditions. Whole cells are considered as the cheapest form of catalyst for bioconversion for many reasons, among which the ready and cheap preparation, no need of expensive cofactor, and the increased enzyme stability because of protective barriers offered by cell compartments. This review highlights some of the most recent advances in the field of biotransformations under flow conditions using whole cells. Different examples are provided where the use of continuous flow techniques enables the development of very efficient processes and multiple reaction steps to be combined into a single continuous operation
What’s new in flow biocatalysis? A snapshot of 2020–2022
No full textFlow biocatalysis is a key enabling technology that is increasingly being applied to a wide array of reactions with the aim of achieving process intensification, better control of biotransformations, and minimization of waste stream. In this minireview, selected applications of flow biocatalysis to the preparation of food ingredients, APIs and fat- and oil-derived commodity chemicals, covering the period 2020-2022, are described
Re-Make/Re-Model: Recent breakthroughs on the road to practicable and diversified biocatalytical processes
No full textBiocatalysis has been traditionally used when high chemo-, regio- and stereoselectivity under mild conditions (pH, pressure, temperature). Contrariwise, low productivity and low catalyst stability generally represent major constraints for obtaining intense preparative processes. Moreover, the diversity of reactions obtainable by biocatalysis is still limited. Indeed, over the last 12 months we have witnessed a large effort to obtain new biocatalysts and intensified transformation processes. Improvement and diversification involve engineering of the different components of that characterize (overall) a biocatalytic process: substrate, medium, protein, biocatalyst and bioreactor engineering. Therefore, we have selected papers of 2017 that meaningfully contributed to the advance of biocatalysis either by improving existing concepts or by suggesting new directions (new reactions, new techniques. Most of these papers are strongly multidisciplinary, entailing techniques and notions from different fields (chemistry, chemical engineering, biochemistry, molecular biology, bioinformatics, microbiology) for engineering and intensifying biocatalytic processes, while a strong effort has been devoted to the design of the catalytic repertoire of natural enzymes to functions new to biological systems
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