Publications by authors named "Knaus T"

The fabrication of stable perovskite nanofilm patterns is important for the development of functional optical devices. However, current production approaches are limited by the requirement for strict inert gas protection and long processing times. Here, a confined flash printing synthesis method is presented to generate perovskite nanofilms under ambient conditions, combining precursor transfer, perovskite synthesis, crystallization, and polymer protection in a single step within milliseconds.

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Asymmetric hydrogenation of alkene moieties is important for the synthesis of chiral molecules, but achieving high stereoselectivity remains a challenge. Biocatalysis using ene-reductases (EReds) offers a viable solution. However, the need for NAD(P)H cofactors limits large-scale applications.

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The styrene monooxygenase, a two-component enzymatic system for styrene epoxidation, was characterised through the study of Fus-SMO - a chimera resulting from the fusion of StyA and StyB using a flexible linker. Notably, it remains debated whether the transfer of FADH from StyB to StyA occurs through diffusion, channeling, or a combination of both. Fus-SMO was identified as a trimer with one bound FAD molecule.

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Recyclable fluorescence assays that can be stored at room temperature would greatly benefit biomedical diagnostics by bringing sustainability and cost-efficiency, especially for point-of-care serodiagnostics in developing regions. Here, a general strategy is proposed to generate recyclable fluorescent probes by using engineered enzymes with enhanced thermo-/chemo-stability, which maintains an outstanding serodiagnostic performance (accuracy >95%) after 10 times of recycling as well as after storage at elevated temperatures (37 °C for 10 days). With these three outstanding properties, recyclable fluorescent probes can be designed to detect various biomarkers of clinical importance by using different enzymes.

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Article Synopsis
  • - Developed a biosensor for uric acid detection using engineered urate oxidase on gold nanoparticles integrated with a carbon-glass electrode
  • - Achieved a low detection limit of 9.16 nM and high sensitivity of 14 μA/μM
  • - The biosensor demonstrated a linear response across a wide range (50 nM to 1 mM) and maintained effectiveness for over 28 days
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The mirror neuron system consists of fronto-parietal regions and responds to both goal-directed action execution and observation. The broader action observation network is specifically involved in observation of actions and is thought to play a role in understanding the goals of the motor act, the intention of others, empathy, and language. Many, but not all, studies have found mirror neuron system or action observation network dysfunction in autism spectrum disorder.

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The efficient asymmetric catalytic synthesis of amines containing more than one stereogenic center is a current challenge. Here, we present a biocatalytic cascade that combines ene-reductases (EReds) with imine reductases/reductive aminases (IReds/RedAms) to enable the conversion of α,β-unsaturated ketones into primary, secondary, and tertiary amines containing two stereogenic centers in very high chemical purity (up to >99%), a diastereomeric ratio, and an enantiomeric ratio (up to >99.8:<0.

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Herein, we show how the merge of biocatalysis with flow chemistry aided by 3D-printing technologies can facilitate organic synthesis. This concept was exemplified for the reductive amination of benzaldehyde catalysed by co-immobilised amine dehydrogenase and formate dehydrogenase in a continuous flow micro-reactor. For this purpose, we investigated enzyme co-immobilisation by covalent binding, or ion-affinity binding, or entrapment.

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Children with chromosome 22q11.2 deletion syndrome (22q11.2DS) exhibit impaired ability to process and understand emotions in others.

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Enantiomerically pure 1,2-amino alcohols are important compounds due to their biological activities and wide applications in chemical synthesis. In this work, we present two multienzyme pathways for the conversion of l-phenylalanine into either 2-phenylglycinol or phenylethanolamine in the enantiomerically pure form. Both pathways start with the two-pot sequential four-step conversion of l-phenylalanine into styrene via subsequent deamination, decarboxylation, enantioselective epoxidation, and enantioselective hydrolysis.

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Peroxidase enzymes enable the construction of electrochemical sensors for highly sensitive and selective quantitative detection of various molecules, pathogens and diseases. Herein, we describe the immobilization of a peroxidase from Bacillus s. (BsDyP) on electrochemically reduced graphene oxide (ERGO) deposited on indium tin oxide (ITO) and polyethylene terephthalate (PET) layers.

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We present a one-pot cascade for the synthesis of phenylpropanolamines (PPAs) in high optical purities (er and dr up to >99.5 %) and analytical yields (up to 95 %) by using 1-phenylpropane-1,2-diols as key intermediates. This bioamination entails the combination of an alcohol dehydrogenase (ADH), an ω-transaminase (ωTA) and an alanine dehydrogenase to create a redox-neutral network, which harnesses the exquisite and complementary regio- and stereo-selectivities of the selected ADHs and ωTAs.

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The l-lysine-ϵ-dehydrogenase (LysEDH) from Geobacillus stearothermophilus naturally catalyzes the oxidative deamination of the ϵ-amino group of l-lysine. We previously engineered this enzyme to create amine dehydrogenase (AmDH) variants that possess a new hydrophobic cavity in their active site such that aromatic ketones can bind and be converted into α-chiral amines with excellent enantioselectivity. We also recently observed that LysEDH was capable of reducing aromatic aldehydes into primary alcohols.

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A NADH-dependent engineered amine dehydrogenase from (LE-AmDH-v1) was applied together with a NADH-oxidase from (NOx) for the kinetic resolution of pharmaceutically relevant racemic α-chiral primary amines. The reaction conditions (e. g.

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We report an enzymatic route for the formal regio- and stereoselective aminohydroxylation of β-methylstyrene that consumes only dioxygen, ammonia and formate; carbonate is the by-product. The biocascade entails highly selective epoxidation, hydrolysis and hydrogen-borrowing alcohol amination. Thus, β-methylstyrene was converted into 1,2 and 1,2-phenylpropanolamine in 59-63% isolated yields, and up to >99.

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Amine dehydrogenases (AmDHs) catalyse the conversion of ketones into enantiomerically pure amines at the sole expense of ammonia and hydride source. Guided by structural information from computational models, we create AmDHs that can convert pharmaceutically relevant aromatic ketones with conversions up to quantitative and perfect chemical and optical purities. These AmDHs are created from an unconventional enzyme scaffold that apparently does not operate any asymmetric transformation in its natural reaction.

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-Chiral amines are pivotal building blocks for chemical manufacturing. Stereoselective amination of alcohols is receiving increased interest due to its higher atom-efficiency and overall improved environmental footprint compared with other chemocatalytic and biocatalytic methods. We previously developed a hydrogen-borrowing amination by combining an alcohol dehydrogenase (ADH) with an amine dehydrogenase (AmDH) .

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In this study, two stereocomplementary ω-transaminases from Arthrobacter sp. (AsR-ωTA) and Chromobacterium violaceum (Cv-ωTA) were immobilized via iron cation affinity binding onto polymer-coated controlled porosity glass beads (EziG). The immobilization procedure was studied with different types of carrier materials and immobilization buffers of varying compositions, concentrations, pHs and cofactor (PLP) concentrations.

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Phenolic compounds present in extra virgin olive oil have recently attracted considerable attention due to their pharmacological activities. Among them oleacein (3,4-DHPEA-EDA), structurally related to oleochantal (4-HPEA-EDA), is one of the most studied. 3,4-DHPEA-EDA has been synthesized through decarboxylation of demethyloleuropein catalyzed by Er(OTf).

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Biocatalytic asymmetric amination of ketones, by using amine dehydrogenases (AmDHs) or transaminases, is an efficient method for the synthesis of α-chiral primary amines. A major challenge is to extend amination to the synthesis of secondary and tertiary amines. Herein, for the first time, it is shown that AmDHs are capable of accepting other amine donors, thus giving access to enantioenriched secondary amines with conversions up to 43 %.

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Herein, we present a study on the oxidation of aldehydes to carboxylic acids using three recombinant aldehyde dehydrogenases (ALDHs). The ALDHs were used in purified form with a nicotinamide oxidase (NOx), which recycles the catalytic NAD at the expense of dioxygen (air at atmospheric pressure). The reaction was studied also with lyophilised whole cell as well as resting cell biocatalysts for more convenient practical application.

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We report an unprecedented catalytically promiscuous activity of the copper-dependent enzyme galactose oxidase. The enzyme catalyses the one-pot conversion of alcohols into the related nitriles under mild reaction conditions in ammonium buffer, consuming ammonia as the source of nitrogen and dioxygen (from air at atmospheric pressure) as the only oxidant. Thus, this green method does not require either cyanide salts, toxic metals, or undesired oxidants in stoichiometric amounts.

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The amination of alcohols is an important transformation in chemistry. The redox-neutral (i.e.

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The exquisite chemoselectivity and the intrinsic compatibility of enzymes have been widely exploited during the past decade for the development of multi-step biocatalytic reactions in one-pot. In this context, hydrogen-borrowing cascades permit to maximise the atom-efficiency through the internal recycling of redox equivalents, which avoids the use of additional oxidants or reductants. Here, we describe the state-of-the-art in the field of biocatalytic hydrogen-borrowing cascades and provide a future perspective for a wider implementation in organic synthesis.

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The styrene monooxygenase (SMO) system from Pseudomonas sp. consists of two enzymes (StyA and StyB). StyB catalyses the reduction of FAD at the expense of NADH.

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