Journal of Molecular Catalysis B: Enzymatic 
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This 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.Tuning Lipase-catalysed Kinetic Resolution of 2-Substituted thiophenes and furans. A Scalable Chemoenzymatic route to masked γ-Bis-Oxo-alcohols.
Publication date: Available online 3 February 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Dartagnan S.P. Ferreira, Jeiely G. Ferreira, Everaldo F.S. Filho, Jefferson L. Princival The demand for greener and applicable approaches aiming at the synthesis of optically active compounds as single enantiomers has seen a significant growth worldwide. Since most of the chemically synthesized compounds are produced as racemates their kinetic resolution has been of great interest. For this purpose a number of chemo-enzymatic approaches were proposed. One of such approaches, the use of isolated lipas...
Source: Journal of Molecular Catalysis B: Enzymatic - February 4, 2016 Category: Biochemistry Source Type: research
Immobilized phospholipase A1-catalyzed acidolysis of phosphatidylcholine from Antarctic krill (Euphausia superba) for docosahexaenoic acid enrichment under supercritical conditions
Publication date: Available online 30 January 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Xuan Xi, Xiaomei Feng, Nianrong Shi, Xixiu Ma, Hong Lin, Yuqian Han This paper describes the use of immobilized phospholipase A1 (PLA1) for the production of phosphatidylcholine (PC) rich in docosahexaenoic acid (DHA) using PC from Antarctic krill and fish fatty acids (FA) as the substrates, and supercritical carbon dioxide (SCCO2) as the solvent medium. Detailed studies of immobilization were performed, and PLA1 was immobilized by physical adsorption onto DA–201. The best conditions for adsorp...
Source: Journal of Molecular Catalysis B: Enzymatic - January 30, 2016 Category: Biochemistry Source Type: research
Design of chromogenic probes for efficient screening and evaluation of feruloyl esterase-like activities
Publication date: Available online 28 January 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Olga Gherbovet, Régis Fauré, Fernando Ferreira, Julien Durand, Mélanie Ragon, Guillaume Hostyn, Eric Record, Sophie Bozonnet, Michael J. O’Donohue Feruloyl esterases (FAEs) constitute an important sub-group of hydrolytic enzymes involved in the deconstruction of plant cell wall polysaccharides. However, in the current era of genomics and metagenomics, finding and characterizing FAEs is not straightforward, mainly due to a lack of suitable compounds for high-throughput assays. To remedy...
Source: Journal of Molecular Catalysis B: Enzymatic - January 29, 2016 Category: Biochemistry Source Type: research
Enhancement of alpha-ketoglutaric acid production from L-glutamic acid by high-cell-density cultivation
In this study, an efficient strategy of high-cell-density cultivation was exploited to obtain recombinant L-glutamate oxidase (LGOX), which was used to produce alpha-ketoglutaric acid (α-KG) from L-glutamic acid. First, lactose was used to replace isopropyl β-D-1-thiogalactopyranoside as a cheaper and more effective inducer. Second, a novel, two-stage feeding strategy was proposed, in which the exponential feeding mode was first performed in a 5-L fermenter until the maximum dissolved oxygen (DO) concentration was reached, which was followed by a DO-stat feeding mode. Based on the two-stage feeding strategy and by optimi...
Source: Journal of Molecular Catalysis B: Enzymatic - January 18, 2016 Category: Biochemistry Source Type: research
Enhanced production of N-acetyl-D-neuraminic acid by whole-cell bio-catalysis of Escherichia coli
In this study, a whole cell process using engineered Escherichia coli strain was developed and stepwise optimization was employed for Neu5Ac production. N-acetyl-D-glucosamine 2-epimerase and Neu5Ac aldolase were overexpressed in E. coli individually and the activity ratio was optimized by varying recombinant amounts of cell biomass for synthesis of Neu5Ac. Moreover, substrate concentrations and ratio of pyruvate and N-acetyl-D-glucosamine (GlcNAc) and detergent concentrations were optimized to increase product synthesis. The resulting process generated 237.4mM Neu5Ac with a yield of 40.0% mol/mol GlcNAc. Furthermore, tran...
Source: Journal of Molecular Catalysis B: Enzymatic - January 16, 2016 Category: Biochemistry Source Type: research
Rational selection of circular permutation sites in characteristic regions of the α/β-hydrolase fold enzyme RhEst1
In this study we performed the CP analysis of the typical esterase RhEst1 to explore the CP site-selection strategy of the α/β-hydrolase fold family. A CP library of 97 mutants was generated to identify the effect of CP on three characteristic regions of RhEst1including the flexible cap domain (Region 1), the region around the entrance to substrate binding pocket (Region 2) and the surface-exposed sectors in catalytic domain (Region 3). We found the protein folding, stability and bioactivity of CP variants were altered significantly and the CP sites of active variants were mainly located in the flexible loops. These stud...
Source: Journal of Molecular Catalysis B: Enzymatic - January 16, 2016 Category: Biochemistry Source Type: research
High-level Expression of Prolyl Endopeptidase in Pichia pastoris Using PLA2 as a Fusion Partner
Publication date: Available online 15 January 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Ting Jiang, Chao Kang, Xiao-Wei Yu, Yan Xu In our previous studies, a prolyl endopeptidase (PEP) gene from Aspergillus oryzae (MOH) was cloned and expressed in Pichia pastoris; however, the recombinant protein expression level of MOH was very low. In the present study, the PEP expression level was successfully improved by constructing fusion expression proteins with four fusion partners, namely, Streptomyces violaceoruber Phospholipase A2 (PLA2), cellulose-binding domain (CBD), small ubiquitin-relate...
Source: Journal of Molecular Catalysis B: Enzymatic - January 16, 2016 Category: Biochemistry Source Type: research
Microbial transformation of androst-4-ene-3,17-dione by three fungal species Absidia griseolla var. igachii, Circinella muscae and Trichoderma virens
Publication date: Available online 15 January 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Marjan Heidary, Zohreh Habibi Microbial transformation of androst-4-ene-3,17-dione (AD;I) by three fungal species including Absidia griseolla var. igachii, Circinella muscae and Trichoderma virens was investigated for the first time. While A. griseolla and C. muscae carried out hydroxylation reactions, the third fungi performed reduction of the 17-carbonyl group in a chemoselective manner. Incubation of AD by A. griseolla yielded four metabolites 6β- (II), 7α- (III), 7β- (VI) and 14α-hydroxy-AD (V), ...
Source: Journal of Molecular Catalysis B: Enzymatic - January 16, 2016 Category: Biochemistry Source Type: research
Effect of Spacer Modification on Enzymatic Synthetic and Hydrolytic Activities of Immobilized Trypsin
Publication date: Available online 13 January 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Julia Andre, David Saleh, Christoph Syldatk, Rudolf Hausmann A thorough comparison of spacer-mediated covalent and non-covalent immobilization of trypsin on micro-magnetic particles was accomplished in the present study. Trypsin was coupled via diaminoalkanes, aminoalkanoic acids, bovine serum albumin (BSA), and biotin-derivate spacers onto magnetic particles. A comparison of resulting synthetic and hydrolytic activities after immobilization was performed. Whereas hydrolytic trypsin activity was meas...
Source: Journal of Molecular Catalysis B: Enzymatic - January 15, 2016 Category: Biochemistry Source Type: research
EndoG: a novel multifunctional halotolerant glucanase and xylanase isolated from cow rumen
Publication date: Available online 14 January 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Inés Loaces, Gualberto Bottini, Guillermo Moyna, Elena Fabiano, Alfredo Martínez, Francisco Noya Lignocellulosic materials represent a sustainable source of chemicals and fuels because of their low cost and ample supply. The current limitations on bioconversion of lignocellulosic biomass include poor enzyme stability and inhibition by secondary or final products. Here, we report the biochemical characterization of a novel, rumen metagenome-derived glucanase and xylanase, named EndoG. From the d...
Source: Journal of Molecular Catalysis B: Enzymatic - January 15, 2016 Category: Biochemistry Source Type: research
The generation of a steroid library using filamentous fungi immobilized in calcium alginate
Publication date: Available online 6 January 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Patrice C. Peart, William F. Reynolds, Paul B. Reese Four fungi, namely, Rhizopus oryzae ATCC 11145, Mucor plumbeus ATCC 4740, Cunninghamella echinulata var. elegans ATCC 8688a, and Whetzelinia sclerotiorum ATCC 18687, were subjected to entrapment in calcium alginate, and the beads derived were used in the biotransformation of the steroids 3β,17β-dihydroxyandrost-5-ene (1) and 17β-hydroxyandrost-4-en-3-one (2). Incubations performed utilized beads from two different encapsulated fungi to explore thei...
Source: Journal of Molecular Catalysis B: Enzymatic - January 12, 2016 Category: Biochemistry Source Type: research
Enzymatic thiol Michael addition using laccases: Multiple CS bond formation between p-hydroquinones and aromatic thiols
Publication date: Available online 7 January 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Max Schlippert, Annett Mikolasch, Veronika Hahn, Frieder Schauer Laccases create CC, CO or CN bonds and have been investigated intensively as catalysts for green chemistry and white biotechnology. However, little is known about CS bond formation in laccase-catalyzed reactions. We have used the laccases from Pycnoporus cinnabarinus and Myceliophthora thermophila to create heteromolecular reaction products from p-hydroquinones and aromatic thiols via CS bond formation. We discovered a broad assortment o...
Source: Journal of Molecular Catalysis B: Enzymatic - January 12, 2016 Category: Biochemistry Source Type: research
A two step process for production of omega 3-polyunsaturated fatty acid concentrates from sardine oil using Cryptococcus sp. MTCC 5455 lipase
Publication date: Available online 7 January 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Mayilvahanan Aarthy, Palanivel Saravanan, Niraikulam Ayyadurai, Marichetti Kuppuswami Gowthaman, Numbi Ramudu Kamini The omega-3 polyunsaturated fatty acid concentrates rich in eicosapentaeonic acid (EPA) and docosahexaenoic acid (DHA) were prepared by a two-step process involving the hydrolysis of sardine oil using lipase obtained from Cryptococcus sp. MTCC 5455 followed by urea complexation. The lipase was produced in a 3.7 L fermenter with an agitator speed of 300 rpm and airflow rate of 1 vv...
Source: Journal of Molecular Catalysis B: Enzymatic - January 12, 2016 Category: Biochemistry Source Type: research
Enzymatic kinetic resolution of aliphatic sec-alcohols by LipG9, a metagenomic lipase
Publication date: Available online 7 January 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Pamela T. Bandeira, Robson C. Alnoch, Alfredo R.M. de Oliveira, Emanuel M.de de Souza, Fábio de O. Pedrosa, Nadia Krieger, Leandro Piovan Bioprospection for new enantioselective enzymes for application in organic synthesis is a prominent area of investigation in biocatalysis. In this context, here we present the evaluation of an immobilized lipase isolated from a metagenomic library (LipG9) for the enzymatic kinetic resolution (EKR) of aliphatic sec-alcohols, which are still challenging substra...
Source: Journal of Molecular Catalysis B: Enzymatic - January 12, 2016 Category: Biochemistry Source Type: research
An integrated approach for the detailed characterization of an immobilized enzyme
Publication date: Available online 8 January 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Filipe Carvalho, Patrizia Paradiso, Benilde Saramago, Ana Maria Ferraria, Ana Maria Botelho do Rego, Pedro Fernandes Enzyme immobilization has been the focus of extensive research over decades, yet empiricism still often prevails over rational design. To overcome this pattern and develop high performance, cost-effective systems, a trend towards a more comprehensive characterization of the heterogeneous bioconversion systems is emerging. This work encompasses such scope. The model system is the imm...
Source: Journal of Molecular Catalysis B: Enzymatic - January 12, 2016 Category: Biochemistry Source Type: research
