Journal of Molecular Catalysis B Enzymatic (J MOL CATAL B-ENZYM)

Publisher: Elsevier

Journal description

The journal is an international forum devoted to research and developments in the applications of whole-cell and cell-free enzymes as catalysts in organic synthesis. Emphasis is focused on mechanistic and synthetic aspects of the biocatalytic transformation.Papers deal with the following topics; Industrial applications of enzymatic processes, e.g. in fine chemical synthesis; Chemo-, regio- and enantioselective transformations; Screening for biocatalysts; Integration of biocatalytic and chemical steps in organic syntheses; Novel biocatalysts, e.g. enzymes from extremophiles and catalytic antibodies; Enzyme immobilization and stabilization, particularly in non-conventional media; Bioprocess engineering aspects, e.g. membrane bioreactors; Improvement of catalytic performance of enzymes, e.g. by protein engineering or chemical modification; Structural studies, including computer simulation, relating to substrate specificity and reaction selectivity; Biomimetic studies related to enzymatic transformations.

Current impact factor: 2.13

Impact Factor Rankings

2016 Impact Factor Available summer 2017
2014 / 2015 Impact Factor 2.128
2013 Impact Factor 2.745
2012 Impact Factor 2.823
2011 Impact Factor 2.735
2010 Impact Factor 2.33
2009 Impact Factor 2.4
2008 Impact Factor 2.015
2007 Impact Factor 1.973
2006 Impact Factor 2.149
2005 Impact Factor 1.685
2004 Impact Factor 1.547
2003 Impact Factor 1.475
2002 Impact Factor 1.451
2001 Impact Factor 1.408
2000 Impact Factor 1.448
1999 Impact Factor 1.126
1998 Impact Factor 1.386
1997 Impact Factor 1.132

Impact factor over time

Impact factor
Year

Additional details

5-year impact 2.62
Cited half-life 5.60
Immediacy index 0.43
Eigenfactor 0.01
Article influence 0.53
Website Journal of Molecular Catalysis B: Enzymatic website
Other titles Journal of molecular catalysis
ISSN 1873-3158
OCLC 39177340
Material type Document, Periodical, Internet resource
Document type Internet Resource, Computer File, Journal / Magazine / Newspaper

Publisher details

Elsevier

  • Pre-print
    • Author can archive a pre-print version
  • Post-print
    • Author can archive a post-print version
  • Conditions
    • Authors pre-print on any website, including arXiv and RePEC
    • Author's post-print on author's personal website immediately
    • Author's post-print on open access repository after an embargo period of between 12 months and 48 months
    • Permitted deposit due to Funding Body, Institutional and Governmental policy or mandate, may be required to comply with embargo periods of 12 months to 48 months
    • Author's post-print may be used to update arXiv and RepEC
    • Publisher's version/PDF cannot be used
    • Must link to publisher version with DOI
    • Author's post-print must be released with a Creative Commons Attribution Non-Commercial No Derivatives License
    • Publisher last reviewed on 03/06/2015
  • Classification
    green

Publications in this journal

  • [Show abstract] [Hide abstract]
    ABSTRACT: 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 their potential for the production of metabolites other than those derived from the individual fungi. The investigation showed that steroids from both single and crossover transformations were typically produced, some of which were hitherto unreported. The results indicated that this general technique can be exploited for the production of small libraries of compounds.
    No preview · Article · Mar 2016 · Journal of Molecular Catalysis B Enzymatic
  • Hong Zhao · Qing Cui · Vishva Shah · Jianhong Xu · Tao Wang

    No preview · Article · Feb 2016 · Journal of Molecular Catalysis B Enzymatic
  • Dartagnan S.P. Ferreira · Jeiely G. Ferreira · Everaldo F.S. Filho · Jefferson L. Princival

    No preview · Article · Feb 2016 · Journal of Molecular Catalysis B Enzymatic
  • [Show abstract] [Hide abstract]
    ABSTRACT: 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 adsorption were as follows: protein loading = 85 mg PLA1/g support at a pH of 5 with 10 h of contact. For synthesis of PC with high levels of DHA, the effects of several parameters, including pressure, reaction time, temperature, enzyme loading and substrate molar ratio, were investigated to determine optimal conditions. The optimal substrate molar ratio of the FA to PC was 10. Under 12 MPa and 50 °C SCCO2, 59.0 mol% DHA was incorporated into PC after only 7 h at an immobilized enzyme loading rate of 15 wt% of the total substrates. The PC yield was 27.5 mol% under the optimal conditions.
    No preview · Article · Jan 2016 · Journal of Molecular Catalysis B Enzymatic
  • [Show abstract] [Hide abstract]
    ABSTRACT: 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 this, indolyl and 4-nitrocatechol hydroxycinnamates (i.e. trans-ferulate and p-coumarate derivatives) were synthesized in good overall yields – between 46 and 56% after 4 steps – and their usefulness as substrates for FAEs was ascertained. The hydrolysis of the ester bond of these chromogenic compounds leads to a colour change, which can be readily monitored. Overall, these compounds considerably improve upon the current situation and enable the measurement of FAE activities in both qualitative solid medium-based and quantitative liquid assays.
    No preview · Article · Jan 2016 · Journal of Molecular Catalysis B Enzymatic
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    ABSTRACT: 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 optimizing the induction strategies, the maximal cell density and LGOX activity reached 48.4 g/L and 156.1 U/mL, respectively, after 20 h of cultivation. When a whole-cell biocatalyst was used, the titer of α-KG was up to 127.2 g/L from 132 g/L L-glutamic acid in 24 h.
    No preview · Article · Jan 2016 · Journal of Molecular Catalysis B Enzymatic
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    ABSTRACT: 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-related modifier (SUMO) and maltose binding protein (MBP). The enzyme activities of the recombinant fusion proteins CLMH, SLMH, MLMH and PLMH were increased to 3.8-, 2.7-, 4.9- and 7.4-fold compared with that of the parent MOH. Moreover, the extracellular protein content of CLMH, SLMH, MLMH, PLMH were 1.42-, 1.25-, 1.67- and 1.83-fold higher compared with that of MOH. Both PLMH and MOH showed the highest activity at pH 5.5, the highest stability at pH 6.0 and maximal activity at 40 °C.
    No preview · Article · Jan 2016 · Journal of Molecular Catalysis B Enzymatic
  • [Show abstract] [Hide abstract]
    ABSTRACT: 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), among which 6β-hydroxy-AD (II) was identified as the major product. Furthermore, the metabolites produced during AD biotransformation by C. muscae were 6β- (II), 7β- (III) and 14α-hydroxy-AD (V). On the other hand, T. virens remarkably reduced AD into testosterone (VI) as the only product with 60% yield. These metabolites were purified by TLC and identified by 1H NMR, 13C NMR and other spectroscopic data.
    No preview · Article · Jan 2016 · Journal of Molecular Catalysis B Enzymatic
  • Fulong Li · Zhengjiao Luan · Qi Chen · Jianhe Xu · Huilei Yu
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    ABSTRACT: Circular permutation (CP) involves the cleavage of polypeptide to obtain new termini, which can result in different protein structures and functions. It has been demonstrated to be an effective strategy for the evolution of proteins, but the lack of principle for selecting CP site to construct functional variants is still a challenge for CP. 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 studies reveal the importance of site-selection for CP and provide more information for CP of other α/β-hydrolases.
    No preview · Article · Jan 2016 · Journal of Molecular Catalysis B Enzymatic
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    ABSTRACT: N-acetyl-D-neuraminic acid (Neu5Ac) has been considerably focused due to its promising potential applications in pharmaceuticals and dairy products. A whole-cell biocatalyst process is an important tool for synthesis of pharmaceutical intermediates and fine chemicals. 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 237.4 mM Neu5Ac with a yield of 40.0% mol/mol GlcNAc. Furthermore, transporter pathways involved in Neu5Ac and GlcNAc were engineered and their impact on the Neu5Ac synthesis was evaluated. Using a stepwise optimization, an overall whole-cell biocatalytic process was developed and a maximum titer of 260.0 mM Neu5Ac (80.4 g/L) with a conversion yield of 43.3% from GlcNAc was achieved. The process can be used for industrial large-scale production of Neu5Ac in terms of efficiency and economy.
    No preview · Article · Jan 2016 · Journal of Molecular Catalysis B Enzymatic
  • [Show abstract] [Hide abstract]
    ABSTRACT: 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 deduced amino acid sequence it was assigned to glycoside hydrolase family 5. EndoG showed similarity to non-characterized proteins, and its parental organism is likely related to the genus Prevotella. The 1146pb ORF encoding EndoG was over-expressed in Escherichia coli and the protein purified. The recombinant EndoG displayed a wide range of pH activity with a maximum at pH 5.0 and at least 65% activity at pH between 4.5 and 7.5. The enzyme was highly stable at 55 °C for 1 hour, and retained 81% activity at 4 M NaCl. EndoG was also active in the presence of diverse divalent cations, detergents, EDTA, acetate, furfural, imidazolium ionic liquids, and ethanol. Glucose or cellobiose had no effect in EndoG performance. EndoG behaved as a multifunctional endo- and exo-glucanase, as well as xylanase, displaying activity on 4-methylumbelliferyl-β-D-cellobioside, p-nitrophenyl-β-D-cellobioside, carboxymethylcellulose (CMC), phosphoric acid swollen cellulose, avicel, xylan, lichenan and sugar cane bagasse. To evaluate its biotechnological potential, ethanologenic E.coli MS04 cells expressing either EndoG or a Thermobifida fusca β-glucosidase were co-cultured in minimal media with avicel or CMC as the sole carbon source attaining 2.0 g/L and 3.3 g/L of ethanol, respectively.
    No preview · Article · Jan 2016 · Journal of Molecular Catalysis B Enzymatic
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    ABSTRACT: 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 measured employing N-α-Benzoyl-DL-arginine 4-nitroanilide (BAPNA) assay, synthetic trypsin activity was measured employing a dipeptide synthesis assay. Within spacer-mediated trypsin immobilization, diaminoalkanes, aminoalkanoic acids and biotin spacers showed an up to 40% increased synthetic specific activity of trypsin compared to the spacer-free method. Within the hydrolytic reaction type, coupling of trypsin via diaminoalkanes and biotin spacers resulted in a specific activity increase of up to 30%. BSA-bound trypsin displayed only minor increasing effects on both activities of trypsin. Furthermore, protein loading-dependent specific synthetic and hydrolytic activities were evaluated for 8-aminooctanoic acid, 12-aminododecanoic acid and 1,12-diamonododecane as spacers and compared to the direct covalent binding method. The protein binding capacity of spacer-modified particles was lower compared to the direct binding method. Synthetic activity of 8-aminooctanoic acid-bound trypsin was higher than in the case of the spacer-free method over a broad protein loading range with an up to 10-fold increase. The hydrolytic activity was increased by 64% using 8-aminooctanoic acid as spacer within a lower protein loading range. Spacer-bound trypsin showed a slightly lowered reusability over ten sequential cycles compared to spacer-free covalent binding method.
    No preview · Article · Jan 2016 · Journal of Molecular Catalysis B Enzymatic
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    ABSTRACT: A gene encoding a thermotolerant endo-1,4-β-mannanase belonging to glycosyl hydrolase family 5 (GH5) was isolated from the fungal strain Trichoderma virens UKM1 (manTV). The aim of this work was to heterologously express and characterize manTV for subsequent applications. The 1,329 bp β-mannanase gene was cloned and expressed in Pichia pastoris X33 yeast cells, and the recombinant mannanase (rMANTV) was expressed as a His6-tagged glycoprotein of approximately 65–70 kDa. The purified rMANTV showed a specific activity of 415.49 Umg−1 for 0.5% locust bean gum (LBG). This enzyme had a high optimum temperature, 70 °C, with stability from 20 °C to 65 °C. The rMANTV had its highest activity at pH 5, with a wide pH stability range of pH 3–9. It was relatively stable in the presence of several metal ions and chemical substances. In addition, rMANTV had Km values of 2.61 mgmL−1 and 1.49 mgmL−1 for LBG and Konjac glucomannan, respectively. Its catalytic efficiency (Kcat/Km) was 225.41 ± 20.14 mLmg−1 s−1 for LBG and 336.67 ± 27.39 mLmg−1 s−1 for Konjac glucomannan. The high temperature tolerance of this endo-1,4-β-mannanase makes it a good potential candidate for industrial applications.
    No preview · Article · Jan 2016 · Journal of Molecular Catalysis B Enzymatic
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    ABSTRACT: 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 vvm at 25 °C. A maximum activity of 60 ± 2 U/mL and a productivity of 0.8 U/mL/h was obtained at 72 h, which was 1.6 times greater than at shake flask level. The concentrated enzyme could hydrolyse sardine oil effectively and the reaction conditions were optimized by central composite rotatable design. A hydrolysis ratio of 83.7% was obtained at 72 h with 1000 U of lipase and 1% (w/v) Triton X-100 concentration. Urea complexation of the hydrolysed sardine oil enriched the contents of EPA and DHA to 44.3% and 11.6%, which were 2.6 and 1.8 times higher than the initial content of the oil. Spectral properties of the enriched PUFA concentrates were evaluated by ATR-FTIR and 1H NMR spectroscopy. PUFA enrichment using native lipase from yeast Cryptococcus sp. was attempted for the first time in this study.
    No preview · Article · Jan 2016 · Journal of Molecular Catalysis B Enzymatic
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    ABSTRACT: The potential of basidiomycetous enzymes for selective alkane CH-functionalizations in aqueous media has been disclosed utilizing surface and submerged cultures. A screening displayed the high catalytic activity of Dichomitus albidofuscus, Pholiota squarrosa, and Abortiporus biennis in aerobic oxidations of adamantane as a model hydrocarbon. With isopropanol as a co-solvent, the oxidation was accelerated significantly without changes of the fungal growth. 1-Adamantanol was obtained in 40% preparative yield from the oxidation of adamantane by D. albidofuscus. The CH-positional selectivity (3°/2°= 3.6) and the deuterium kinetic isotopic effect (kH/kD = 2.25) values provide evidence for the participation of fungal metalloenzymes in the CH-activation step.
    No preview · Article · Dec 2015 · Journal of Molecular Catalysis B Enzymatic
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    ABSTRACT: Five glucosidases were studied with respect to their ability to catalyse the transglycosylation of maltose or cellobiose. Experiments were carried out at high substrate concentrations to increase the ratio between transglycosylation and hydrolysis. The properties of the enzymes were quite different, and as a simple descriptor of transglycosylation ability we suggest the use of the acceptor concentration (in this case, the disaccharide concentration) required to achieve the same initial rate in transglycosylation as in hydrolysis. We call this descriptor T50. Aspergillus Niger transglucosidase had the lowest T50 value (30 mM) and produced panose as the major product from maltose with a 69% yield after 6 h. With a longer incubation time, secondary hydrolysis occurred and isomaltose could be obtained with a 65% yield. Aspergillus Niger glucosidase was the most efficient enzyme for the transglycosylation of cellobiose with a T50 value of 130 mM. It produced mainly cellotriose with the 1,6-linked trisaccharide (6-O-β-glucopyranosyl-cellobiose) as a side product. Almond β-glucosidase had a T50 value much higher than 320 mM (the highest concentration tested), and it produced 6-O-β-glucopyranosyl-cellobiose as the main transglycosylation product.
    No preview · Article · Dec 2015 · Journal of Molecular Catalysis B Enzymatic
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    ABSTRACT: A domino reaction for the synthesis of 2-amino-4H-chromene derivatives using bovine serum albumin (BSA) as a catalyst in ethanol was described. The domino Michael addition/intramolecular cyclization reactions of readily available 2-hydroxychalcones with malononitrile gave the desired products in yields of 31-96% under the optimized conditions. As an example of biocatalytic methods, this work not only broadens the BSA-catalyzed chemical transformations, but also could be a potential valuable tool in organic synthesis in view of the economical and sustainable catalyst and simple operation.
    No preview · Article · Dec 2015 · Journal of Molecular Catalysis B Enzymatic