Intrinsic dissolution kinetics and topochemistry of xylan, mannan, and lignin during auto-hydrolysis of red maple wood meal

2019 ◽  
Vol 97 (3) ◽  
pp. 649-661 ◽  
Author(s):  
Rory Jara ◽  
Martin Lawoko ◽  
Adriaan van Heiningen
Keyword(s):  
Dissolution Kinetics ◽  
Red Maple ◽  
Intrinsic Dissolution ◽  
Wood Meal ◽  
Hydrolysis Of

ISOLATION AND PROPERTIES OF A GLUCOMANNAN FROM THE WOOD OF RED MAPLE (ACER RUBRUM L.)

1960 ◽  
Vol 38 (9) ◽  
pp. 1511-1517 ◽  
Author(s):  
A. Jabbar Mian ◽  
T. E. Timell
Keyword(s):  
Acer Rubrum ◽  
Partial Hydrolysis ◽  
Red Maple ◽  
Glycosidic Bonds ◽  
Linear Molecules ◽  
Hydrolysis Of

A glucomannan has been isolated from the wood of red maple (Acer rubrum L.) in a yield corresponding to 92% of the mannose residues in this wood and with a ratio of mannose to glucose of 2:1. Partial hydrolysis of the polysaccharide yielded 4-O-β-D-mannopyranosyl-D-mannose, 4-O-β-D-mannopyranosyl-D-glucose, 4-O-β-D-glucopyranosyl-D-mannose, 4-O-β-D-glucopyranosyl-D-glucose, and O-β-D-mannopyranosyl-(l → 4)-O-β-D-mannopyranosyl-(1 → 4)-D-mannose. The methylated glucomannan on hydrolysis gave a mixture of di-O-methylhexoses, 2,3,6-tri-O-methyl-D-mannose, 2,3,6-tri-O-methyl-D-glucose, and 2,3,4,6-tetra-O-methyl-D-glucose in a mole ratio of 7:29:13:1. The methylated polysaccharide contained 55 hexose residues per average molecule, while the corresponding value for the nitrate derivative was 67. It is concluded that the glucomannan is composed of a minimum of 70 glucose and mannose residues linked together by (1 → 4)-β-glycosidic bonds to linear molecules. The glucose residues are probably interposed between two or three contiguous mannose residues.

scholarly journals Hopping intermittent contact-scanning electrochemical microscopy (HIC-SECM) as a new local dissolution kinetic probe: application to salicylic acid dissolution in aqueous solution

CrystEngComm ◽  
2015 ◽  
Vol 17 (41) ◽  
pp. 7835-7843 ◽  
Author(s):  
Amelia R. Perry ◽  
Robert A. Lazenby ◽  
Maria Adobes-Vidal ◽  
Massimo Peruffo ◽  
Kim McKelvey ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Salicylic Acid ◽  
Dissolution Kinetics ◽  
Scanning Electrochemical Microscopy ◽  
Dissolution Kinetic ◽  
Acid Dissolution ◽  
Intrinsic Dissolution ◽  
Intermittent Contact ◽  
Local Dissolution ◽  
Electrochemical Microscopy

Transiently induced dissolution of salicylic acid crystals reveals initial intrinsic dissolution kinetics.

Modeling xylan solubilization during autohydrolysis of sugar maple wood meal: Reaction kinetics

Holzforschung ◽  
2009 ◽  
Vol 63 (3) ◽  
Author(s):  
Ashutosh Mittal ◽  
Siddharth G. Chatterjee ◽  
Gary M. Scott ◽  
Thomas E. Amidon
Keyword(s):  
Sugar Maple ◽  
Batch Reactor ◽  
Reaction Times ◽  
Wood Meal ◽  
Diffusion Limitations ◽  
Reaction Rate Constants ◽  
Solid Ratio ◽  
First Order Kinetics ◽  
Kinetics Of ◽  
Hydrolysis Of

Abstract The objective of this work was to study the kinetics of hemicelluloses extraction during hydrothermal pretreatment of sugar maple wood meal. Pretreatment was conducted in a batch reactor at 145–185°C with reaction times up to 8 h and with liquor to solid ratio of 20:1. Under these conditions, hemicelluloses were selectively solubilized and little degradation (approximately 6–9% of the initial amount) of cellulose and lignin was observed. A kinetic model was developed. It was supposed that there are no diffusion limitations and that the reaction rate constants have first-order kinetics with Arrhenius-type temperature dependence. The model proposes the formation of xylose directly from wood xylan as well as from xylooligomers formed in the liquid phase by the hydrolysis of xylan. The model is able to correlate satisfactorily experimentally measured yields of residual xylan, xylooligomers, xylose, and furfural obtained during the pretreatment.

Fine Structural Localization of Acyltransferases Involved in Lipid Synthesis in Intestinal Mucosa.

1970 ◽  
Vol 28 ◽  
pp. 54-55
Author(s):  
R. J. Barrnett ◽  
J. A. Higgins
Keyword(s):  
Smooth Endoplasmic Reticulum ◽  
Lipid Synthesis ◽  
Mucosal Cell ◽  
Structural Localization ◽  
Morphological Studies ◽  
Mucosal Cells ◽  
Initial Appearance ◽  
Sh Group ◽  
Hydrolysis Of ◽  
Intestinal Mucosal Cells

The main products of intestinal hydrolysis of dietary triglycerides are free fatty acids and monoglycerides. These form micelles from which the lipids are absorbed across the mucosal cell brush border. Biochemical studies have indicated that intestinal mucosal cells possess a triglyceride synthesising system, which uses monoglyceride directly as an acylacceptor as well as the system found in other tissues in which alphaglycerophosphate is the acylacceptor. The former pathway is used preferentially for the resynthesis of triglyceride from absorbed lipid, while the latter is used mainly for phospholipid synthesis. Both lipids are incorporated into chylomicrons. Morphological studies have shown that during fat absorption there is an initial appearance of fat droplets within the cisternae of the smooth endoplasmic reticulum and that these subsequently accumulate in the golgi elements from which they are released at the lateral borders of the cell as chylomicrons.We have recently developed several methods for the fine structural localization of acyltransferases dependent on the precipitation, in an electron dense form, of CoA released during the transfer of the acyl group to an acceptor, and have now applied these methods to a study of the fine structural localization of the enzymes involved in chylomicron lipid biosynthesis. These methods are based on the reduction of ferricyanide ions by the free SH group of CoA.

Lattice imaging and pore structure of β ferric oxyhydroxide

1978 ◽  
Vol 36 (1) ◽  
pp. 264-265
Author(s):  
T. Baird ◽  
J.R. Fryer ◽  
S.T. Galbraith
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Bulk Material ◽  
Model Structure ◽  
Bulk Crystals ◽  
Lattice Imaging ◽  
Thin Sections ◽  
Ferric Oxyhydroxide ◽  
Resolution Electron ◽  
Hydrolysis Of

Introduction Previously we had suggested (l) that the striations observed in the pod shaped crystals of β FeOOH were an artefact of imaging in the electron microscope. Contrary to this adsorption measurements on bulk material had indicated the presence of some porosity and Gallagher (2) had proposed a model structure - based on the hollandite structure - showing the hollandite rods forming the sides of 30Å pores running the length of the crystal. Low resolution electron microscopy by Watson (3) on sectioned crystals embedded in methylmethacrylate had tended to support the existence of such pores.We have applied modern high resolution techniques to the bulk crystals and thin sections of them without confirming these earlier postulatesExperimental β FeOOH was prepared by room temperature hydrolysis of 0.01M solutions of FeCl3.6H2O, The precipitate was washed, dried in air, and embedded in Scandiplast resin. The sections were out on an LKB III Ultramicrotome to a thickness of about 500Å.

Elucidating cyclic AMP signaling in subcellular domains with optogenetic tools and fluorescent biosensors

2019 ◽  
Vol 47 (6) ◽  
pp. 1733-1747 ◽  
Author(s):  
Christina Klausen ◽  
Fabian Kaiser ◽  
Birthe Stüven ◽  
Jan N. Hansen ◽  
Dagmar Wachten
Keyword(s):  
Cyclic Amp ◽  
Adenosine Monophosphate ◽  
Adenylyl Cyclases ◽  
Temporal Precision ◽  
Fluorescent Biosensors ◽  
Subcellular Domains ◽  
Spatio Temporal ◽  
Hydrolysis Of ◽  
Shed Light ◽  
Cyclic Amp Signaling

The second messenger 3′,5′-cyclic nucleoside adenosine monophosphate (cAMP) plays a key role in signal transduction across prokaryotes and eukaryotes. Cyclic AMP signaling is compartmentalized into microdomains to fulfil specific functions. To define the function of cAMP within these microdomains, signaling needs to be analyzed with spatio-temporal precision. To this end, optogenetic approaches and genetically encoded fluorescent biosensors are particularly well suited. Synthesis and hydrolysis of cAMP can be directly manipulated by photoactivated adenylyl cyclases (PACs) and light-regulated phosphodiesterases (PDEs), respectively. In addition, many biosensors have been designed to spatially and temporarily resolve cAMP dynamics in the cell. This review provides an overview about optogenetic tools and biosensors to shed light on the subcellular organization of cAMP signaling.

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