Center in Green Chemistry and Catalysis

Montréal, Canada

Center in Green Chemistry and Catalysis

Montréal, Canada
Time filter
Source Type

Pons A.,French National Center for Scientific Research | Beucher H.,French National Center for Scientific Research | Ivashkin P.,French National Center for Scientific Research | Lemonnier G.,French National Center for Scientific Research | And 4 more authors.
Organic Letters | Year: 2015

An efficient access to highly functionalized monofluorocyclopropanes is described. The developed methodology allowed straightforward access to a large panel of polysubstituted fluorinated cyclopropanes in good to excellent yields and good diastereoselectivities. The Rh-catalyzed cyclopropanation proved to be efficient on several fluorinated olefins and several diazo compounds. This method represents the first general route to complex fluorinated cyclopropanes. © 2015 American Chemical Society.

Morley K.L.,National Research Council Canada | Grosse S.,National Research Council Canada | Leisch H.,National Research Council Canada | Lau P.C.K.,National Research Council Canada | And 2 more authors.
Green Chemistry | Year: 2013

Canolol (4-vinylsyringol, VS), a potent antioxidant and an alkylperoxyl radical scavenger originally discovered in crude canola oil (rapeseed), is produced by decarboxylation of sinapic acid (SA) during canola seed roasting. Chemical syntheses of VS from SA require thermal or microwave induced decarboxylation in the presence of a base. A laboratory-evolved enzyme, designated SA decarboxylase (SAD), was developed in this study. In a biphasic bioreactor system, SAD was shown to produce VS from SA extracts prepared from canola meal with an overall yield of 3.0 mg VS per g of canola meal. In addition, we investigated the application of VS in polymerization to produce polyvinylsyringol (PVS) as a potential biodegradable polymer. The characteristics of PVS determined by thermogravimetric analysis, differential scanning calorimetry and nanoindentation tests are described. © 2013 The Royal Society of Chemistry.

Xiao Z.,National Research Council Canada | Grosse S.,National Research Council Canada | Bergeron H.,National Research Council Canada | Lau P.C.K.,National Research Council Canada | And 2 more authors.
Applied Microbiology and Biotechnology | Year: 2014

The only available genome sequence for Rhizopus oryzae strain 99-880 was annotated to not encode any β-1,4-endoxylanase encoding genes of the glycoside hydrolase (GH) family 10 or 11. Here, we report the identification and cloning of two such members in R. oryzae strain NRRL 29086. Strain 29086 was one of several selected fungi grown on wheat or triticale bran and screened for xylanase activity among other hydrolytic actions. Its high activity (138 U/ml) in the culture supernatant led to the identification of two activity-stained proteins, designated Xyn-1 and Xyn-2 of respective molecular masses 32,000 and 22,000. These proteins were purified to electrophoretic homogeneity and characterized. The specific activities of Xyn-1 and Xyn-2 towards birchwood xylan were 605 and 7,710 U/mg, respectively. Kinetic data showed that the lower molecular weight Xyn-2 had a higher affinity (Km = 3.2 ± 0.2 g/l) towards birchwood xylan than Xyn-1 by about 4-fold. The melting temperature (Tm) of the two proteins, estimated to be in the range of 49.5–53.7 °C indicated that they are rather thermostable proteins. N-terminal and internal peptide sequences were obtained by chemical digestion of the purified xylanases to facilitate cloning, expression in Escherichia coli, and sequencing of the respective gene. The cloned Rhizopus xylanases were used to demonstrate release of xylose from flax shives-derived hemicellulose as model feedstock. Overall, this study expands the catalytic toolbox of GH10 and 11 family proteins that have applications in various industrial and bioproducts settings. © 2014, Her Majesty the Queen in Right of Canada.

Iwaki H.,Kansai University | Grosse S.,National Research Council Canada | Bergeron H.,National Research Council Canada | Leisch H.,National Research Council Canada | And 5 more authors.
Applied and Environmental Microbiology | Year: 2013

Whereas the biochemical properties of the monooxygenase components that catalyze the oxidation of 2,5-diketocamphane and 3,6-diketocamphane (2,5-DKCMO and 3,6-DKCMO, respectively) in the initial catabolic steps of (+) and (-) isomeric forms of camphor (CAM) metabolism in Pseudomonas putida ATCC 17453 are relatively well characterized, the actual identity of the flavin reductase (Fred) component that provides the reduced flavin to the oxygenases has hitherto been ill defined. In this study, a 37-kDa Fred was purified from a camphor-induced culture of P. putida ATCC 17453 and this facilitated cloning and characterization of the requisite protein. The active Fred is a homodimer with a subunit molecular weight of 18,000 that uses NADH as an electron donor (Km(32 μM), and it catalyzes the reduction of flavin mononucleotide (FMN) (Km=3.6 μM; kcat=283 s-1) in preference to flavin adenine dinucleotide (FAD) (Km(19 μM; kcat(128 s-1). Sequence determination of~40 kb of the CAM degradation plasmid revealed the locations of two isofunctional 2,5-DKCMO genes (camE25-1 for 2,5-DKCMO-1 and camE25-2 for 2,5-DKCMO-2) as well as that of a 3,6-DKCMO-encoding gene (camE36). In addition, by pulsed-field gel electrophoresis, the CAM plasmid was established to be linear and~533 kb in length. To enable functional assessment of the two-component monooxygenase system in Baeyer-Villiger oxidations, recombinant plasmids expressing Fred in tandem with the respective 2,5-DKCMO- and 3,6-DKCMO-encoding genes in Escherichia coli were constructed. Comparative substrate profiling of the isofunctional 2,5-DCKMOs did not yield obvious differences in Baeyer-Villiger biooxidations, but they are distinct from 3,6-DKCMO in the stereoselective oxygenations with various mono- and bicyclic ketone substrates. © 2013, American Society for Microbiology.

Leisch H.,NRC Biotechnology Research Institute | Grosse S.,NRC Biotechnology Research Institute | Iwaki H.,Kansai University | Hasegawa Y.,Kansai University | And 2 more authors.
Canadian Journal of Chemistry | Year: 2012

The biocatalytic performance of a cloned cyclohexylamine oxidase derived from Brevibacterium oxydans IH-35A towards structurally different amines was investigated. Cycloalkyl primary amines, alkyl aryl amines, and α-carbon-substituted aliphatic amines were identified as suitable substrates for the biocatalyst based on an activity assay. Kinetic resolutions of several amines by either recombinant whole cells or crude enzyme extracts prepared therefrom gave enantiomerically pure (R)-amines besides the corresponding ketones. When cyclohexylamine oxidase in combination with a borane-ammonia complex as reducing agent was applied to the deracemization of several substrates, excellent enantiomeric ratios (>99:1) and good isolated yields (62%-75%) of the corresponding (R)-amines were obtained. © 2012 Published by NRC Research Press.

Leisch H.,NRC Biotechnology Research Institute | Shi R.,McGill University | Grosse S.,NRC Biotechnology Research Institute | Morley K.,NRC Biotechnology Research Institute | And 9 more authors.
Applied and Environmental Microbiology | Year: 2012

A dimeric Baeyer-Villiger monooxygenase (BVMO) catalyzing the lactonization of 2-oxo-Δ3-4,5,5-trimethylcyclopentenylacetylcoenzyme A (CoA), a key intermediate in the metabolism of camphor by Pseudomonas putida ATCC 17453, had been initially characterized in 1983 by Ougham and coworkers (H. J. Ougham, D. G. Taylor, and P. W. Trudgill, J. Bacteriol. 153:140 -152, 1983). Here we cloned and overexpressed the 2-oxo-Δ3-4,5,5-trimethylcyclopentenylacetyl-CoA monooxygenase (OTEMO) in Escherichia coli and determined its three-dimensional structure with bound flavin adenine dinucleotide (FAD) at a 1.95-Å resolution as well as with bound FAD and NADP+ at a 2.0-Å resolution. OTEMO represents the first homodimeric type 1 BVMO structure bound to FAD/NADP+. A comparison of several crystal forms of OTEMO bound to FAD and NADP+ revealed a conformational plasticity of several loop regions, some of which have been implicated in contributing to the substrate specificity profile of structurally related BVMOs. Substrate specificity studies confirmed that the 2-oxo-Δ3-4,5,5-trimethylcyclopentenylacetic acid coenzyme A ester is preferred over the free acid. However, the catalytic efficiency (kcat/Km) favors 2-n-hexyl cyclopentanone (4.3×105M-1 s-1) as a substrate, although its affinity (Km=32 μM) was lower than that of the CoA-activated substrate (Km=18 μM). In whole-cell biotransformation experiments, OTEMO showed a unique enantiocomplementarity to the action of the prototypical cyclohexanone monooxygenase (CHMO) and appeared to be particularly useful for the oxidation of 4-substituted cyclohexanones. Overall, this work extends our understanding of the molecular structure and mechanistic complexity of the type 1 family of BVMOs and expands the catalytic repertoire of one of its original members. © 2012, American Society for Microbiology.

Hexagonally well-organized ZnCl2-OMA materials have been successfully synthesized by a one-pot approach using a sol-gel method at ambient temperature and pressure. These materials were prepared through simultaneous self-assembly process with F127 as directing agent combined with in situ impregnation of ZnCl2. The new approach was found to be compatible with various common aluminium precursors and carboxylic acids used as self-assembly interfacial protectors. The obtained ZnCl2-OMA materials were fully characterized using XRD, N2 adsorption-desorption, TEM, SEM, EDX, XPS and 1H and 27Al MAS-NMR techniques. These materials were compared with the zinc chloride-doped organized mesoporous alumina (ZnCl2-OMA) supports prepared through a conventional two steps process that includes OMA synthesis and then post-synthesis incorporation of ZnCl2. Thus, the one-pot synthesized materials were found to exhibit improved properties compared to the conventional ones, particularly larger BET surface area. The synthesized ZnCl2-OMA materials were then used as catalytic supports for methyltrioxorhenium (MTO), showing enhanced catalytic performance for methyl oleate self-metathesis, demonstrating better activity and selectivity towards desired metathesis products. These features are highly beneficial for large-scale materials synthesis through fast, simple, easy and low-cost introduction of functionalities on mesoporous materials surface without multi-step procedures. © The Royal Society of Chemistry.

Pham M.-H.,Laval University | Pham M.-H.,Center in Green Chemistry and Catalysis | Vuong G.-T.,Laval University | Vuong G.-T.,Center in Green Chemistry and Catalysis | And 4 more authors.
Crystal Growth and Design | Year: 2012

Nanocubes and nanosheets of [Cu 2(ndc) 2(dabco)] n metal-organic framework (ndc = 1,4-naphthalene dicarboxylate; dabco = 1,4-diazabicyclo[2.2.2]octane) were synthesized by using simultaneously acetic acid and pyridine or only pyridine, respectively, as selective modulators. This approach can tailor crystal growing on different directions for the size- and shape-controlled synthesis of metal-organic framework (MOF) nanocrystals whose structure is composed of two or more types of linkers using selective modulators. These MOF nanocrystals exhibit high crystallinity and higher CO 2 uptakes compared to that of the bulk MOF material or of the [Cu 2(ndc) 2(dabco)] n nanorods generated by using only acetic acid as the selective modulator, which may be due to the morphology effect on their gas sorption properties. © 2012 American Chemical Society.

Ortgies D.H.,Concordia University at Montréal | Ortgies D.H.,Center in Green Chemistry and Catalysis | Forgione P.,Concordia University at Montréal | Forgione P.,Center in Green Chemistry and Catalysis
Synlett | Year: 2013

A ligand-free Pd-catalyzed cross-coupling of aryl sulfinates with aryl bromides has been developed. A variety of aryl bromides and aryl sulfinates undergo this transformation to yield the desired biaryl in a practical and economical manner. © Georg Thieme Verlag Stuttgart New York.

Gundersen M.T.,University of Montréal | Gundersen M.T.,Center in Green Chemistry and Catalysis | Keillor J.W.,Center in Green Chemistry and Catalysis | Keillor J.W.,University of Ottawa | And 2 more authors.
Applied Microbiology and Biotechnology | Year: 2014

The great importance of amide bonds in industrial synthesis has encouraged the search for efficient catalysts of amide bond formation. Microbial transglutaminase (MTG) is heavily utilized in crosslinking proteins in the food and textile industries, where the side chain of a glutamine reacts with the side chain of a lysine, forming a secondary amide bond. Long alkylamines carrying diverse chemical entities can substitute for lysine as acyl-acceptor substrates, to link molecules of interest onto peptides or proteins. Here, we explore short and chemically varied acyl-acceptor substrates, to better understand the nature of nonnatural substrates that are tolerated by MTG, with the aim of diversifying biocatalytic applications of MTG. We show, for the first time, that very short-chain alkyl-based amino acids such as glycine can serve as acceptor substrates. The esterified α-amino acids Thr, Ser, Cys, and Trp - but not Ile - also showed reactivity. Extending the search to nonnatural compounds, a ring near the amine group - particularly if aromatic - was beneficial for reactivity, although ring substituents reduced reactivity. Overall, amines attached to a less hindered carbon increased reactivity. Importantly, very small amines carrying either the electron-rich azide or the alkyne groups required for click chemistry were highly reactive as acyl-acceptor substrates, providing a robust route to minimally modified, "clickable" peptides. These results demonstrate that MTG is tolerant to a variety of chemically varied natural and nonnatural acyl-acceptor substrates, which broadens the scope for modification of Gln-containing peptides and proteins. © 2013 Springer-Verlag Berlin Heidelberg.

Loading Center in Green Chemistry and Catalysis collaborators
Loading Center in Green Chemistry and Catalysis collaborators