biocatalysis and enzyme

A bimetallic organic gel was prepared by mixing the bridging ligand 2,4,6-tri(4-carboxyphenyl)-1,3,5-triazine with Cu(II) and Co(II) ions at room temperature. The resulting metal-organic gel (MOG) shows enhanced peroxidase-like activity, most likely due to the synergetic redox cycling between Co(III)/Co(II) and Cu(II)/Cu(I) pairs. These accelerate interfacial electron transfer and generation of hydroxy radicals. The MOG can catalyze the reaction of H2 O2 with terephthalic acid (TPA), producing a blue fluorescence product with the maximum excitation/emission at 315/446 nm...

BACKGROUND: Immobilization is an appropriate tool to ease the handling and recycling of enzymes in biocatalytic processes and to increase their stability. Most of the established immobilization methods require case-to-case optimization, which is laborious and time-consuming. Often, (chromatographic) enzyme purification is required and stable immobilization usually includes additional cross-linking or adsorption steps. We have previously shown in a few case studies that the molecular biological fusion of an aggregation-inducing tag to a target protein induces the intracellular formation of protein aggregates, so called inclusion bodies (IBs), which to a certain degree retain their (catalytic) function...

To achieve efficient one-step production of gluconic acid, cascade reactions of glucose oxidase (GOD) and catalase (CAT) have been advocated in the biocatalysis system. In this work, the methodology of co-immobilization of GOD and CAT was investigated in details for obtaining improved enzyme loading and activity. The maximum adsorption capability of GOD and CAT was 24.18 and 14.33 mg·g-1 , respectively. The matching between dimensions of enzymes and hierarchical pore sizes of carriers are critical to the success of immobilization process...

The biocatalytic activity of transglutaminases (TGs) leads to the synthesis of new covalent isopeptide bonds (crosslinks) between peptide-bound glutamine and lysine residues, but also the transamidation of primary amines to glutamine residues, which ultimately can result into protein polymerisation. Operating with a cysteine/histidine/aspartic acid (Cys/His/Asp) catalytic triad, TGs induce the post-translational modification of proteins at both physiological and pathological conditions (e.g., accumulation of matrices in tissue fibrosis)...

Coenzymes are ubiquitous in Nature, assisting in enzyme-catalysed reactions. Several coenzymes, nicotinamides and flavins, have been known for close to a century, whereas variations of those organic molecules have more recently come to light. In general, the requirement of these coenzymes imposes certain constraints for in vitro enzyme use in biocatalytic processes. Alternative coenzymes have risen to circumvent the cost factor, tune reaction rates or obtain different chemical reactivity. This review will focus on these alternatives and their role and applications in biocatalysis...

Deep eutectic solvents (DES) are a class of neoteric solvents used in multiple applications amongst which biocatalytic processes. Due to its simple preparation, low cost and inherent biodegradable properties, its use as a non-volatile biocompatible co-solvent with both whole cells and isolated enzymes has displayed increased enzyme activity and stability translating to higher product conversions and a surprising higher enantioselectivity in a range of biotransformations. This review lays out the latest updates on the use of DES in redox biocatalytic reactions...

A bioinspired strategy for the synthesis of supramolecular and biocatalytical materials was developed base on protein-protein supramolecular interaction and genetic engineering. Formate dehydrogenase (FDH) and its functional fragments were separately fused to form a multi-function domain. The fusion proteins and functional fragments self-assembled into the expanded and controllable supramolecular interaction networks. Morphology characterization by scanning-electron microscopy showed that the assembled functional fragments and fusion proteins formed multi-dimensional (3D) and two-dimensional (2D) layer-like structures...

Reactions that were once the exclusive province of synthetic catalysts can increasingly be addressed using biocatalysis. Through discovery of non-natural enzyme reactions, biochemists have significantly expanded the reach of enzymatic catalysis to include carbene transfer chemistries including olefin cyclopropanation. Here we describe hemoprotein cyclopropanation catalysts derived from thermophilic bacterial globins that react with diazoacetone and an unactivated olefin substrate to furnish a cyclopropyl ketone, a previously unreported reaction for enzyme catalysts...

Biocatalysis has developed enormously in the last decade and now offers solutions for the sustainable production of chiral and highly functionalised asset molecules. Products generated by enzymatic transformations are already being used in the food, feed, chemical, pharmaceutical and cosmetic industry, and the accessible compound panoply is expected to expand even further. In particular, the combination of stereo-selective enzymes in linear cascade reactions is an elegant strategy toward enantiomeric pure compounds, as it reduces the number of isolation and purification steps and avoids accumulation of potentially unstable intermediates...

Biocatalysis is attracting interest in the chemical industry as a sustainable alternative in large-scale chemical transformations. However, low operational stability of naturally evolved enzymes is a challenge and major efforts are required to engineer protein stability, usually by directed evolution. The development of methods for protein stabilization based on rational design is of great interest, as it would minimize the efforts needed to generate stable enzymes. We hereby present a rational design strategy based on proline substitutions in flexible areas of the protein identified by analyzing B-factors...

Solvent-tolerant bacteria represent an interesting option to deal with substrate and product toxicity in bioprocesses. Recently, constitutive solvent tolerance was achieved for Pseudomonas taiwanensis VLB120 via knockout of the regulator TtgV, making tedious adaptation unnecessary. Remarkably, ttgV knockout increased styrene epoxidation activities of P. taiwanensis VLB120ΔC. With the aim to characterize and exploit the biocatalytic potential of P. taiwanensis VLB120ΔC and VLB120ΔCΔttgV, we investigated and correlated growth physiology, native styrene monooxygenase (StyAB) gene expression, whole-cell bioconversion kinetics, and epoxidation performance...

Redox biocatalysis has come to the forefront because of its excellent catalytic efficiency, stereoselectivity, and environmental benignity. The green and sustainable biotransformation can be driven by photoelectrochemical (PEC) platforms where redox biocatalysis is coupled with photoelectrocatalysis. The main challenge is how to transfer photoexcited electrons to (or from) the enzyme redox centers for effective biotransformation using solar energy. This review commences with a conceptual discussion of biocatalytic PEC platforms and highlights recent advances in PEC-based biotransformation through cofactor regeneration or direct transfer of charge carriers to (or from) oxidoreductases on enzyme-conjugated electrodes...

Lignocellulosic biomass is a feedstock with the potential to be converted into value-added bioproducts. The use of enzymatic hydrolysis allows the cleavage of lignocellulose into their monomeric units, but there are some drawbacks that make its use in industrial biocatalysis unfeasible. In the present study, we describe the hydrolysis of brewer's spent grain (BSG) with an enzymatic cocktail produced by Aspergillus niger CECT 2700 and its comparison with commercial enzymes. In addition, it was determined whether pretreating the BSG (non-pressurized alkaline hydrolysis or treatment with cholinium glycinate ionic liquid) is necessary...

The high catalytic efficiency of enzymes under reaction conditions is one of the main goals in biocatalysis. Despite the dramatic progress in the development of more efficient biocatalysts by protein design, the search for natural enzymes with useful properties remains a promising strategy. The PLP-dependent transaminases represent a group of industrially important enzymes due to their ability to stereoselectively transfer amino groups between diverse substrates; however, the complex mechanism of substrate recognition and conversion makes the design of transaminases a challenging task...

Nitrilase enzymes (EC 3.5.5.1) are responsible for the direct hydration of nitriles to their corresponding carboxylic acids and ammonia. The utilization of nitrilase enzymes in biocatalysis toward bio-pharmaceuticals and industrial applications facilitates the move towards green chemistry. The body of research presented describes a novel clade-specific touchdown PCR protocol for the detection of novel nitrilase genes. The presented study identified partial sequences of 15 novel nitrilase genes across 7 genera, with partial DNA sequence homology (%) displayed across an additional 16 genera...

One of the major challenges in chemical synthesis is the selective oxyfunctionalization of non-activated C-H bonds, which can be enabled by biocatalysis using cytochrome P450 monooxygenases. In this study, we report on the characterization of the versatile CYP109Q5 from Chondromyces apiculatus DSM436, which is able to functionalize a wide range of substrates (terpenes, steroids and drugs), including the ring of β-ionone in non-allylic positions. The crystal structure of CYP109Q5 revealed flexibility within the active site pocket that permitted the accommodation of bulky substrates, and enabled a structure-guided approach to engineering the enzyme...

In this research we report the biological synthesis of electrically conducting polymer - Polypyrrole (Ppy). Cell-assisted enzymatic polymerization/oligomerization of Ppy was achieved using whole cell culture and cell-free crude enzyme extract from two white-rot fungal cultures. The selected fungal strains belong to Trametes spp., known laccase producers, commonly applied in bioremediation and bioelectrochemical fields. The biocatalytic reaction was initiated in situ through the copper-containing enzymes biosynthesized within the cell cultures under submerged aerobe cultivation conditions...

As industrial biocatalysis is maturing, access to enzymatic activities beyond chiral resolutions, asymmetric ketone reductions and reductive aminations is gradually becoming reality. Especially the utilization of carbon-hydrogen bond (C-H) activating enzymes is very attractive as they catalyze a variety of chemically extremely challenging transformations. Because of their intrinsic complexity, the use of these enzymes in manufacturing has been limited. However, recent advances in enzyme engineering and bioinformatics have led to activity improvements for native and non-native substrates, the introduction of new-to-nature chemistries and the identification of promising novel enzyme families...

In 2014, the first fungal pyrroloquinoline-quinone (PQQ)-dependent enzyme was discovered as a pyranose dehydrogenase from the basidiomycete Coprinopsis cinerea (CcPDH). This discovery laid the foundation for a new Auxiliary Activities (AA) family, AA12, in the Carbohydrate-Active enZymes (CAZy) database and revealed a novel enzymatic activity potentially involved in biomass conversion. This review summarizes recent progress made in research on this fungal oxidoreductase and related enzymes. CcPDH consists of the catalytic PQQ-binding AA12 domain, an N-terminal cytochrome b AA8 domain, and a C-terminal family 1 carbohydrate-binding module (CBM1)...

In the course of their development, industrial biocatalysis processes have to be optimized in small-scale, e. g., within microfluidic bioreactors. Recently, we introduced a novel microfluidic reactor device, which can handle defined reaction compartments of up to 250 μL in combination with magnetic micro carriers. By transferring the magnetic carriers between subsequent compartments of differing compositions, small scale synthesis, and bioanalytical assays can be conducted. In the current work, this device is modified and extended to broaden its application range to the screening and optimization of bioprocesses applying immobilized enzymes...