Hydroxynitrile lyases covalently immobilized in continuous flow microreactors

Helm, Michelle P. van der; Bracco, Paula A.; Busch, Hanna; Szymańska, Katarzyna; Jarzębski, Andrzej B.; Hanefeld, Ulf

doi:10.1039/c8cy02192a

Cited by 43 publications

(73 citation statements)

References 67 publications

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“…These results are circa six and seven-fold lower as compared to the best specific rate in flow (0.1 mL) and batch respectively reported in this study. In another study [17], the continuous flow synthesis of (S)-mandelonitrile with immobilized HbHNL on a siliceous monolith microreactor was 8 times faster as compared to the batch system and displayed a specific rate of 0.50 mmol min −1 g enzyme −1 at circa 95% conversion and 0.2 mL min −1 .…”

Section: Comparison Between Batch and Continuous Flow Systemsmentioning

confidence: 99%

“…Indeed, the ability of MeHNL to form tetramers in solution whereas AtHNL forms dimers, explained the superior stability to higher temperatures and lower pH-values observed for MeHNL as compared to AtHNL [31]. Similarly, MeHNL proved to be more stable than dimeric Hevea brasiliensis HNL (HbHNL) for the synthesis of (S)-mandelonitrile in a monolith microreactor [17]. The formation of MeHNL tetrameric structures was attributed as the most likely reason for its higher stability.…”

Section: Batch Reactionsmentioning

confidence: 99%

“…Silica carriers, such as EziG Opal, are known to catalyze the chemical racemic background reaction [15][16][17][18][19]33,34] ( Figures S2 and S3). However, the enantioselectivities achieved here in batch reactions under the optimized immobilization condition demonstrated the efficient suppression of this undesired reaction.…”

Section: Batch Reactionsmentioning

confidence: 99%

“…Given the hydrophilic surface of His 6 -tagged AtHNL [13], its immobilization was performed on EziG Opal. Moreover, EziG Opal has been found to be suitable for reactions in organic solvents [14], a crucial property to enable the synthesis of enantiopure cyanohydrins together with low pH required in the reaction medium [5,[15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

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Immobilization of Arabidopsis thaliana Hydroxynitrile Lyase (AtHNL) on EziG Opal

et al. 2020

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Arabidopsis thaliana hydroxynitrile lyase (AtHNL) catalyzes the selective synthesis of (R)-cyanohydrins. This enzyme is unstable under acidic conditions, therefore its immobilization is necessary for the synthesis of enantiopure cyanohydrins. EziG Opal is a controlled porosity glass material for the immobilization of His-tagged enzymes. The immobilization of His6-tagged AtHNL on EziG Opal was optimized for higher enzyme stability and tested for the synthesis of (R)-mandelonitrile in batch and continuous flow systems. AtHNL-EziG Opal achieved 95% of conversion after 30 min of reaction time in batch and it was recycled up to eight times with a final conversion of 80% and excellent enantioselectivity. The EziG Opal carrier catalyzed the racemic background reaction; however, the high enantioselectivity observed in the recycling study demonstrated that this was efficiently suppressed by using citrate/phosphate buffer saturated methyl-tert-butylether (MTBE) pH 5 as reaction medium. The continuous flow system achieved 96% of conversion and excellent enantioselectivity at 0.1 mL min−1. Lower conversion and enantioselectivity were observed at higher flow rates. The specific rate of AtHNL-EziG Opal in flow was 0.26 mol h−1 genzyme−1 at 0.1 mL min−1 and 96% of conversion whereas in batch, the immobilized enzyme displayed a specific rate of 0.51 mol h−1 genzyme−1 after 30 min of reaction time at a similar level of conversion. However, in terms of productivity the continuous flow system proved to be almost four times more productive than the batch approach, displaying a space-time-yield (STY) of 690 molproduct h−1 L−1 genzyme−1 compared to 187 molproduct h−1 L−1 genzyme−1 achieved with the batch system.

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Section: Comparison Between Batch and Continuous Flow Systemsmentioning

confidence: 99%

Section: Batch Reactionsmentioning

confidence: 99%

Section: Batch Reactionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Immobilization of Arabidopsis thaliana Hydroxynitrile Lyase (AtHNL) on EziG Opal

et al. 2020

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“…Our attention is focused on finding a more efficient and green synthesis method of β-amino acid esters based on aromatic amines. In recent years, more and more reports have been published on enzymatic reactions in continuous-flow microreactors due to their advantages of improving process efficiency and material transfer [26][27][28]. The small size of the continuous-flow microreactors facilitates control of the reaction parameters, which can reduce waste generation and increase productivities [29][30][31].…”

Section: Introductionmentioning

confidence: 99%

Continuous-Flow Synthesis of β-Amino Acid Esters by Lipase-Catalyzed Michael Addition of Aromatic Amines

Long

Xue

et al. 2020

Catalysts

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A continuous-flow procedure for the synthesis of β-amino acid esters has been developed via lipase-catalyzed Michael reaction of various aromatic amines with acrylates. Lipase TL IM from Thermomyces lanuginosus was first used to catalyze Michael addition reaction of aromatic amines. Compared with other methods, the salient features of this work include green reaction conditions (methanol as reaction medium), short residence time (30 min), readily available catalyst and a reaction process that is easy to control. This enzymatic synthesis of β-amino acid esters performed in continuous-flow microreactors is an innovation that provides a new strategy for the fast biotransformation of β-amino acid esters.

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Hydroxynitrile Lyase Discovery, Engineering, and Promiscuity towards Asymmetric Synthesis: Recent Progress

Priya,

Padhi

2023

Eur J Org Chem

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Hydroxynitrile lyases (HNLs) primarily catalyze the stereoselective synthesis of cyanohydrins, but some of them also carry out asymmetric nitroaldol synthesis (Henry reaction). By virtue of the importance of asymmetric C‐C bond formation, and the wide application of chiral cyanohydrins and β‐nitroalcohols, HNLs have gained significance in organic synthesis. Over the years new HNLs have been discovered and their synthetic scope are evaluated. Engineering of HNLs has contributed towards increasing not only the catalytic toolbox but also broad substrate selectivity, stereoselectivity, enzyme stability and application of the enzymes for different transformations other than the conventional ones. This review describes the recent discoveries of diverse hydroxynitrile lyases, and the developments to date since 2016, with respect to their biocatalytic applications in the asymmetric synthesis using both natural and promiscuous reactions.

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Hydroxynitrile lyases covalently immobilized in continuous flow microreactors

Abstract: Enzymes are supreme catalysts when it comes to high enantiopurities and their immobilization will pave the way for continuous operation.

Cited by 43 publications

References 67 publications

Immobilization of Arabidopsis thaliana Hydroxynitrile Lyase (AtHNL) on EziG Opal

Immobilization of Arabidopsis thaliana Hydroxynitrile Lyase (AtHNL) on EziG Opal

Continuous-Flow Synthesis of β-Amino Acid Esters by Lipase-Catalyzed Michael Addition of Aromatic Amines

Hydroxynitrile Lyase Discovery, Engineering, and Promiscuity towards Asymmetric Synthesis: Recent Progress

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