scholarly journals Gel-Type and Macroporous Cross-Linked Copolymers Functionalized with Acid Groups for the Hydrolysis of Wheat Straw Pretreated with an Ionic Liquid

Catalysts ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 675 ◽  
Author(s):  
Giulia Lavarda ◽  
Silvia Morales-delaRosa ◽  
Paolo Centomo ◽  
Jose M. Campos-Martin ◽  
Marco Zecca ◽  
...  

Several sulfonated cross-linked copolymers functionalized with hydroxyl and carboxylic groups have been synthesized. The amount of the cross-linking monomer was tailored (from 4% up to 40%) to tune the resulting micro- and nano-morphologies, and two types of catalysts, namely, gel-type and macroreticular catalysts, were obtained. These copolymers were employed in the catalytic hydrolysis of wheat straw pretreated in 1-ethyl-3-methylimidazolium acetate to obtain sugars. Remarkably, the presence of additional oxygenated groups enhances the catalytic performances of the polymers by favoring the adsorption of β-(1,4)-glucans and makes these materials significantly more active than an acidic resin bearing only sulfonic groups (i.e., Amberlyst 70). In addition, the structure of the catalyst (gel-type or macroreticular) appears to be a determining factor in the catalytic process. The gel-type structure provides higher glucose concentrations because the morphology in the swollen state is more favorable in terms of the accessibility of the catalytic centers. The observed catalytic behavior suggests that the substrate diffuses within the swollen polymer matrix and indirectly confirms that the pretreatment based on dissolution/precipitation in ionic liquids yields a substantial enhancement of the conversion of lignocellulosic biomass to glucose in the presence of heterogeneous catalysts.

2008 ◽  
Vol 153 (1-3) ◽  
pp. 116-126 ◽  
Author(s):  
Luís C. Duarte ◽  
Talita Silva-Fernandes ◽  
Florbela Carvalheiro ◽  
Francisco M. Gírio

1996 ◽  
Vol 27 (1-2) ◽  
pp. 167-173 ◽  
Author(s):  
Zhaoqi Zhan ◽  
Martin Müllner ◽  
Johannes A. Lercher

Langmuir ◽  
2003 ◽  
Vol 19 (6) ◽  
pp. 2188-2192 ◽  
Author(s):  
Steven T. Frey ◽  
Benjamin M. Hutchins ◽  
Brian J. Anderson ◽  
Teresa K. Schreiber ◽  
Michael E. Hagerman

2013 ◽  
Vol 726-731 ◽  
pp. 535-538
Author(s):  
Tian Cheng Liu ◽  
Yu Jiao Guo ◽  
Ping Ning ◽  
Guang Yang Tang ◽  
Ming Long Yuan

Catalytic hydrolysis decomposition of dichlorodifluoromethane (CCl2F2) in the presence of water vapor and oxygen was studied over solid acid MoO3/ZrO2 using a fixed-bed reactor. The CCl2F2 adsorption was multilayer chemical adsorption and its process was corresponding with Freundlich model. Its heat was from 56.3 to 73.2 KJ.mol-1, and it was exothermic reaction and chemical adsorption.


2006 ◽  
Vol 188 (21) ◽  
pp. 7609-7616 ◽  
Author(s):  
Alicia Monroe ◽  
Peter Setlow

ABSTRACT The Bacillus subtilis spore coat protein GerQ is necessary for the proper localization of CwlJ, an enzyme important in the hydrolysis of the peptidoglycan cortex during spore germination. GerQ is cross-linked into high-molecular-mass complexes in the spore coat late in sporulation, and this cross-linking is largely due to a transglutaminase. This enzyme forms an ε-(γ-glutamyl) lysine isopeptide bond between a lysine donor from one protein and a glutamine acceptor from another protein. In the current work, we have identified the residues in GerQ that are essential for transglutaminase-mediated cross-linking. We show that GerQ is a lysine donor and that any one of three lysine residues near the amino terminus of the protein (K2, K4, or K5) is necessary to form cross-links with binding partners in the spore coat. This leads to the conclusion that all Tgl-dependent GerQ cross-linking takes place via these three lysine residues. However, while the presence of any of these three lysine residues is essential for GerQ cross-linking, they are not essential for the function of GerQ in CwlJ localization.


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