Journal of Molecular Catalysis B: Enzymatic Journal of Molecular Catalysis B: Enzymatic RSS feedThis is an RSS file. You can use it to subscribe to this data in your favourite RSS reader or to display this data on your own website or blog.

Chemoenzymatic Total Synthesis of (+)- & amp; ( −)-cis-Osmundalactone
Publication date: Available online 12 November 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Fabian Blume, Yu-Chang Liu, Daniel Thiel, Jan Deska Both optical antipodes of the cis-isomers of osmundalactone, a hydroxypyranone natural product and core structure of the angiopterlactones, have been synthesized from acetylfuran in only three steps through a redox cascade utilizing oxidoreductases and transition metal catalysis in a concerted fashion. The key step in this fully catalytic strategy is the enzyme-mediated Achmatowicz reaction via selective furan oxygenation to furnish the pyran core struct...
Source: Journal of Molecular Catalysis B: Enzymatic - November 11, 2016 Category: Biochemistry Source Type: research

An engineered outer membrane pore enables an efficient oxygenation of aromatics and terpenes
In this study we employed an engineered FhuA Δ1-160 variant in which the “cork domain” was removed (first 160 residues are deleted); FhuA Δ1-160 has a cross-section of 39–46Å with a “free” inner diameter of about 14 Å that serves as passive diffusion channel. FhuA WT and Δ1-160 were coexpressed on a bicistronic system with two P450 BM3 variants for regiospecific hydroxylation of aromatic compounds toluene and anisole as well as for oxidation of two terpenes (α)-pinene and (R)-(+)-limonene. The presence of FhuA Δ1‐160 resulted in a doubled product concentration for toluene (35μ to 50μM), anisole (25μM ...
Source: Journal of Molecular Catalysis B: Enzymatic - November 10, 2016 Category: Biochemistry Source Type: research

Determination of optimum conditions for glucose-6-phosphate dehydrogenase immobilization on chitosan-coated magnetic nanoparticles and its characterization
Publication date: Available online 10 November 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Selmihan Sahin, Ismail Ozmen Chitosan-coated magnetic nanoparticles (CMNPs) were synthesized by co-precipitating Fe2+ and Fe3+ with ammonia in chitosan solution. After activation of CMNPs with glutaraldehyde (GA), G6PD enzyme was immobilized on these nanoparticles. The structure of CMNP was characterized by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), vibrating sample magnetometer VSM, and TEM techniques. The influences of immobilization time, a...
Source: Journal of Molecular Catalysis B: Enzymatic - November 9, 2016 Category: Biochemistry Source Type: research

An unusual feruloyl esterase from Aspergillus oryzae: two tryptophan residues play a crucial role for the activity
In this study, we cloned the AofaeD coding sequence into Pichia pastoris and demonstrated heterologous expression and secretion of active recombinant enzyme (rAoFaeD) as a 30-kDa protein in the culture medium. Purified rAoFaeD exhibited optimal activity at pH 7.0 and at 45°C, but was stable at a pH range of 7.0–10.0 and a temperature of 40°C. While wild-type rAoFaeD failed to cleave the methyl esters of ferulic acid (MFA), p-coumaric acid (MpCA), caffeic acid (MCA), and sinapic acid (MSA) and ethyl ester of ferulic acid (EFA), enzyme exhibited esterase activity when wheat arabinoxylan was used as a substrate, and this ...
Source: Journal of Molecular Catalysis B: Enzymatic - November 9, 2016 Category: Biochemistry Source Type: research

Wickerhamomyces subpelliculosus as whole-cell biocatalyst for stereoselective bioreduction of ketones
Publication date: Available online 9 November 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Viktória Bódai, László Nagy-Győr, Róbert Örkényi, Zsófia Molnár, Szabolcs Kohári, Balázs Erdélyi, Zsuzsanna Nagymáté, Csaba Romsics, Csaba Paizs, László Poppe, Gábor Hornyánszky Newly isolated strains of Wickerhamomyces subpelliculosus were recognized as excellent whole-cell biocatalyst for bioreduction of various ketones. The biocatalytic properties of the new strains were demonstrated in this study by stereoselective bioreduction of acetophenone 1a, 2-heptanone 1b, phenylacetone...
Source: Journal of Molecular Catalysis B: Enzymatic - November 8, 2016 Category: Biochemistry Source Type: research

Characterization of the monolignol oxidoreductase AtBBE-like protein 15 L182V for biocatalytic applications
In this report, we explore the potential of a monolignol oxidoreductase from Arabidopsis thaliana (AtBBE-like protein 15) as biocatalyst for oxidative reactions. For this study we employed a variant with enhanced reactivity towards oxygen, which was obtained by a single amino acid exchange (L182V). The pH and temperature optima of the purified AtBBE-like protein 15 L182V were determined as well as the tolerance toward organic co-solvents; furthermore the substrate scope was characterized. The enzyme has a temperature optimum of 50°C and retains more than 50% activity between pH 5 and pH 10 within 5minutes. The enzyme show...
Source: Journal of Molecular Catalysis B: Enzymatic - November 8, 2016 Category: Biochemistry Source Type: research

Detoxification of furanic and phenolic lignocellulose derived inhibitors of yeast using laccase immobilized on bacterial cellulosic nanofibers
Publication date: Available online 9 November 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Thiyagarajan Saravanakumar, Han-Sung Park, Ae-Young Mo, Myoung-Suk Choi, Dae-Hyuk Kim, Seung-Moon Park Biotransformation of lignocellulose by microbial fermentation is usually preceded by thermo-chemical pretreatments followed by enzymatic hydrolysis of cellulose. Derivatives formed during the pretreatment of the lignocellulosic biomass inhibit enzymatic hydrolysis as well as microbial fermentation. Pretreated lignocellulose hydrolysate contains many derivatives of either furanic or phenolic inhibitory d...
Source: Journal of Molecular Catalysis B: Enzymatic - November 8, 2016 Category: Biochemistry Source Type: research

Thermostability enhancement of xylanase Aspergillus fumigatus RT-1
This study aimed to improve the thermostability of endo-1,4-β-xylanase (afxynG1) from Aspergillus fumigatus RT-1 using error-prone PCR. Since the wild type enzyme has an optimum temperature stability at 50°C, the improvement of its stability will widen its application in industries with operating processes at higher temperatures. A library containing approximately 5,000 afxynG1 mutants was generated and thermally screened at 60°C for 30min. Four mutants (T16A/T39I/L176Q, S68R, A60D and Q47P/S159R) were selected for enzymatic characterization because of their higher catalytic activity compared to the wild type. Among the...
Source: Journal of Molecular Catalysis B: Enzymatic - November 4, 2016 Category: Biochemistry Source Type: research

A new member of family 8 polysaccharide lyase Chondroitin AC lyase (PsPL8A) from Pedobacter saltans displays endo- and exo-lytic catalysis
Publication date: Available online 4 November 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Aruna Rani, Arun Goyal Chondroitin lyases are therapeutically important enzymes. The functional aspects of a chondroitin AC lyase (PsPL8A) from Pedobacter saltans DSM12145 were investigated. PsPL8A was cloned in to pET28a(+) vector, expressed in E. coli BL-21(DE3) cells exhibited a molecular size of approximately, 77kDa. PsPL8A displayed maximum activity with chondroitin 4-sulphate, C4S (489Umg−1) followed by chondroitin 6-sulphate, C6S (214Umg−1) and hyaluronic acid (43.2Umg−1). PsPL8A was maximally a...
Source: Journal of Molecular Catalysis B: Enzymatic - November 3, 2016 Category: Biochemistry Source Type: research

Genetic modification and optimization of endo-inulinase for the enzymatic production of oligofructose from inulin
Publication date: Available online 3 November 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Jiang-Ke Yang, Ji-Wen Zhang, Lin Mao, Xun You, Guang-Jun Chen The enzymatic hydrolyzation of inulin by endo-inulinase to produce oligofructoses, a new type of food additive and health product, is a promising, “green”, and environmentally friendly technique. To identify novel genetic sources of endo-inulinase genes and facilitate their industrial application for oligofructose production, we cloned an endo-inulinase gene from a Fusarium oxysporum strain and achieved high-level expression in the genetica...
Source: Journal of Molecular Catalysis B: Enzymatic - November 2, 2016 Category: Biochemistry Source Type: research

Laccase-catalyzed dimerization of glycosylated lignols
Publication date: Available online 2 November 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Ivan Bassanini, Paolo Gavezzotti, Daniela Monti, Jana Krejzová, Vladimír Křen, Sergio Riva Phenylpropanoid glucosides (PPGs) are naturally occurring and bioactive phenolic derivatives, largely distributed in plants. In this work different PPGs have been chemically or enzymatically synthesized from the lignols coniferyl and p-coumaryl alcohols as substrates for a laccase-catalyzed oxidative coupling. The biooxidation of these PPGs has been investigated here and novel dihydrobenzofuran-based structurall...
Source: Journal of Molecular Catalysis B: Enzymatic - November 1, 2016 Category: Biochemistry Source Type: research

Chemodivergent fungal oxidation of isochroman
Publication date: Available online 29 October 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Gabriela I. Furque, Fabricio R. Bisogno, Virginia E. Sosa This work extends the present knowledge about the ability of filamentous fungi and Baker’s Yeast to selectively transform oxygen-containing compounds. Here, it has been demonstrated that several species of the Aspergillus genus are able to perform selective oxidation of benzopyrans. Isochroman or 3,4-dihydro-1H-benzopyran (1) was chosen as model substrate for the biotransformation since related motifs are often found in the structure of natural pro...
Source: Journal of Molecular Catalysis B: Enzymatic - October 30, 2016 Category: Biochemistry Source Type: research

Intensifying the O2-dependent heterogeneous biocatalysis: superoxygenation of solid support from H2O2 by a catalase tailor-made for effective immobilization
Publication date: Available online 29 October 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Juan M. Bolivar, Sabine Schelch, Martin Pfeiffer, Bernd Nidetzky Besides merely destroying H2O2, an important use of the catalase reaction, H2O2 → 1/2 O2 +H2O, is to supply O2 to oxygenation reactions. Due to convenient spatiotemporal control over O2 release, oxygenation from H2O2 is useful in particular for enzymatic reactions confined to solid supports. Because commercial catalases are difficult to immobilize, we have developed a one-step procedure of purification and immobilization of Bordetella pertu...
Source: Journal of Molecular Catalysis B: Enzymatic - October 28, 2016 Category: Biochemistry Source Type: research

Oxidative biotransformations of phenol substrates catalysed by toluene dioxygenase: a molecular docking study
This study provides insight into the binding interactions by molecular docking using AutoDock tools. The nature of binding of phenolic substrates was of major interest, in order to explain the observed regio- and stereo-selectiviy of product formation. The ellipse-shaped binding pocket of TDO consists of a polar and a hydrophobic region, limiting the possible substrate orientations. The phenolic hydroxyl group was preferentially hydrogen bonded with Gln-215 and His-311 in the active site. In some cases, a hydrogen bond was formed with other amino acids, e.g. Asp-219and Met-220, instead. The position and type of the substit...
Source: Journal of Molecular Catalysis B: Enzymatic - October 27, 2016 Category: Biochemistry Source Type: research

Characterization of recombinant β- galactosidase and its use in enzymatic synthesis of lactulose from lactose and fructose
This study provides an alternative method for enzymatic synthesis of lactulose. Graphical abstract (Source: Journal of Molecular Catalysis B: Enzymatic)
Source: Journal of Molecular Catalysis B: Enzymatic - October 22, 2016 Category: Biochemistry Source Type: research