Electron microscopy of reaction-controlling association structures in the enzymatic hydrolysis of triglycerides

1993 ◽  
Vol 97 (43) ◽  
pp. 11344-11349 ◽  
Author(s):  
Adam W. Mazur ◽  
Janet L. Burns ◽  
George D. Hiler ◽  
Richard J. Spontak
BioResources ◽  
2019 ◽  
Vol 14 (1) ◽  
pp. 1653-1667
Author(s):  
Yawen Zhou ◽  
Jian Yang ◽  
Cong Luo ◽  
Bo Yang ◽  
Changyao Liu ◽  
...  

The effect of metal ions and surfactants on the enzymatic hydrolysis of pretreated wheat straw lignocellulose was investigated. Scanning electron microscopy, infrared spectrum analysis, dynamic light scattering, and fluorescence spectra analysis were used to characterize the influence of Fe3+/ polyoxyethylene (20) sorbitan monooleate (Tween 80). The interaction between Fe3+/Tween 80 and enzyme was further investigated by enzyme kinetics and enzyme activity measurements. The best synergistic effect was obtained when the ratio of Fe3+ and Tween 80 was 0.06. The scanning electron microscopy images showed that the Fe3+/Tween 80 combination was associated with high porosity substrates. The infrared spectrum analysis indicated that the components of the substrates depended on additive types. The highest relative enzymatic activity increase rate was obtained with added Fe3+/ Tween 80. The Vmax and Km values of the group with added Fe3+/Tween 80 were much higher than that of the group without additives. With the addition of Fe3+/ Tween 80, the intensity of the fluorescence emission peak decreased and the peak shifted towards a longer wavelength.


1959 ◽  
Vol 6 (2) ◽  
pp. 163-170 ◽  
Author(s):  
Russell J. Barrnett ◽  
George E. Palade

Experiments which combined histochemistry and electron microscopy were performed in studying the sites of enzymatic hydrolysis of thiolacetic acid in the presence of lead ions in diaphragmatic and cardiac muscle. It was found that in these striated muscles the electron opaque, final product of the histochemical reaction (PbS) was discretely deposited on the swelling of the thick elemental filaments that occurs at the M band. Additional sites of enzymatic activity occurred in mitrochondria and in round sarcoplasmic bodies. A reaction, probably non-enzymatic, also occurred in contraction bands in the area of the Z bands and in the sarcoplasmic reticulum. To ascertain the enzymatic nature of the reaction and to define the enzyme involved, control experiments were carried out and the effect of various esterase inhibitors was assayed. It is suggested that the M band enzyme is a cholinesterase, but the enzymes in the mitochondria and the sarcoplasmic bodies that hydrolyze the substrate appear to be different. A possible role of the M band enzyme is discussed.


1973 ◽  
Vol 51 (6) ◽  
pp. 1147-1153 ◽  
Author(s):  
James L. Harris ◽  
Willard A. Taber

The composition of the cell walls of synnemal and vegetative hyphae of Ceratocystis ulmi was studied by fractionation and assay of released compounds. Residues after enzymatic hydrolyses were examined by electron microscopy. The synnemal wall was found to have 67% carbohydrate, 4.52% amino sugar, 5.02% protein, 1.6% lipid, and 0.59% ash, which accounted for 78.7% of the cell wall. The vegetative hyphal wall contained 56% carbohydrate, 3.44% amino sugar, 7.92% protein, 4.5% lipid, and 1.45% ash, which totaled 73.3% of the wall weight. Sugars identified were D-glucose, D-mannose, D-galactose, and L-rhamnose. Enzymatic hydrolysis of both wall types by cellulase and laminaranase indicated the presence of beta-1,3 and beta-1,4 linkages of glucose polymers. N-acetylglucosamine was liberated by chitinase. Most of the 16 amino acids detected in each wall type were at least twice as abundant in vegetative hyphal walls as in synnemal hyphal walls. Cellulase and laminaranase treatment of cell walls revealed a fibrillar structure. Chitinase-treated walls did not appear as fibrous, suggesting that the fibrous structure may be mostly chitinous. Synnemal cell walls are covered by electron-dense granules which may correspond to the pigment in the synnemal hyphae.


Holzforschung ◽  
2013 ◽  
Vol 67 (8) ◽  
pp. 891-897 ◽  
Author(s):  
Zengqian Shi ◽  
Zhiyong Cai ◽  
Siqun Wang ◽  
Qixin Zhong ◽  
Joseph J. Bozell

Abstract To improve the conversion of enzymatic hydrolysis of biomass in an energy-efficient manner, two short-time ultrasonication strategies were applied on six types of biomass with different structures and components. The strategies include pre-sonication before the hydrolysis and intermittent sonication during the ongoing hydrolysis. The microstructures of each type of biomass were characterized by scanning electron microscopy to investigate the potential correlation between biomass structure and ultrasonicaton. The concentration of resultant reducing sugar was measured to evaluate the efficiency of the hydrolysis. The results indicate that hydrolysis efficiency greatly depends on the initial structures of biomass and that short-time ultrasonication can yield up to 27.5% improvement in hydrolysis efficiency with only 120 s of sonication.


Author(s):  
T. Baird ◽  
J.R. Fryer ◽  
S.T. Galbraith

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.


Author(s):  
Marcin Lukasiewicz ◽  
Anna Osowiec ◽  
Magdalena Marciniak

2018 ◽  
Author(s):  
Ángel Batallas ◽  
Erenio González ◽  
Carmen Salvador ◽  
Jonathan Villavicencio ◽  
Humberto González Gavilánez ◽  
...  

2019 ◽  
Vol 15 (3) ◽  
pp. 296-303 ◽  
Author(s):  
Swapnil Gaikwad ◽  
Avinash P. Ingle ◽  
Silvio Silverio da Silva ◽  
Mahendra Rai

Background: Enzymatic hydrolysis of cellulose is an expensive approach due to the high cost of an enzyme involved in the process. The goal of the current study was to apply magnetic nanomaterials as a support for immobilization of enzyme, which helps in the repeated use of immobilized enzyme for hydrolysis to make the process cost-effective. In addition, it will also provide stability to enzyme and increase its catalytic activity. Objective: The main aim of the present study is to immobilize cellulase enzyme on Magnetic Nanoparticles (MNPs) in order to enable the enzyme to be re-used for clean sugar production from cellulose. Methods: MNPs were synthesized using chemical precipitation methods and characterized by different techniques. Further, cellulase enzyme was immobilized on MNPs and efficacy of free and immobilized cellulase for hydrolysis of cellulose was evaluated. Results: Enzymatic hydrolysis of cellulose by immobilized enzyme showed enhanced catalytic activity after 48 hours compared to free enzyme. In first cycle of hydrolysis, immobilized enzyme hydrolyzed the cellulose and produced 19.5 ± 0.15 gm/L of glucose after 48 hours. On the contrary, free enzyme produced only 13.7 ± 0.25 gm/L of glucose in 48 hours. Immobilized enzyme maintained its stability and produced 6.15 ± 0.15 and 3.03 ± 0.25 gm/L of glucose in second and third cycle, respectively after 48 hours. Conclusion: This study will be very useful for sugar production because of enzyme binding efficiency and admirable reusability of immobilized enzyme, which leads to the significant increase in production of sugar from cellulosic materials.


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