Soluble enzyme cross-linking via multi-component reactions: a new generation of cross-linked enzymes

2020 ◽  
Vol 56 (67) ◽  
pp. 9683-9686
Author(s):  
Maryam Ashjari ◽  
Maryam Garmroodi ◽  
Faezeh Ahrari ◽  
Maryam Yousefi ◽  
Mehdi Mohammadi
Keyword(s):  
Cross Linking ◽  
Soluble Enzyme ◽  
New Generation

Production of CLEs using a multi-component reaction.

scholarly journals Preparation of Stable Cross-Linked Enzyme Aggregates (CLEAs) of a Ureibacillus thermosphaericus Esterase for Application in Malathion Removal from Wastewater

Catalysts ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 154 ◽  
Author(s):  
Yuliya Samoylova ◽  
Ksenia Sorokina ◽  
Alexander Piligaev ◽  
Valentin Parmon
Keyword(s):  
Response Surface Methodology ◽  
Bovine Serum Albumin ◽  
High Stability ◽  
Municipal Wastewater ◽  
Maximal Activity ◽  
Cross Linking ◽  
Soluble Enzyme ◽  
Initial Activity ◽  
E Coli ◽  
Ureibacillus Thermosphaericus

In this study, the active and stable cross-linked enzyme aggregates (CLEAs) of the thermostable esterase estUT1 of the bacterium Ureibacillus thermosphaericus were prepared for application in malathion removal from municipal wastewater. Co-expression of esterase with an E. coli chaperone team (KJE, ClpB, and ELS) increased the activity of the soluble enzyme fraction up to 200.7 ± 15.5 U mg−1. Response surface methodology (RSM) was used to optimize the preparation of the CLEA-estUT1 biocatalyst to maximize its activity and minimize enzyme loss. CLEA-estUT1 with the highest activity of 29.4 ± 0.5 U mg−1 (90.6 ± 2.7% of the recovered activity) was prepared with 65.1% (w/v) ammonium sulfate, 120.6 mM glutaraldehyde, and 0.2 mM bovine serum albumin at 5.1 h of cross-linking. The biocatalyst has maximal activity at 80 °С and pH 8.0. Analysis of the properties of CLEA-estUT1 and free enzyme at 50–80 °C and pH 5.0–10.0 showed higher stability of the biocatalyst. CLEA-estUT1 showed marked tolerance against a number of chemicals and high operational stability and activity in the reaction of malathion hydrolysis in wastewater (up to 99.5 ± 1.4%). After 25 cycles of malathion hydrolysis at 37 °С, it retained 55.2 ± 1.1% of the initial activity. The high stability and reusability of CLEA-estUT1 make it applicable for the degradation of insecticides.

scholarly journals Immobilization of Papain on Chitin and Chitosan and Recycling of Soluble Enzyme for Deflocculation of Saccharomyces cerevisiae from Bioethanol Distilleries

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Douglas Fernandes Silva ◽  
Henrique Rosa ◽  
Ana Flavia Azevedo Carvalho ◽  
Pedro Oliva-Neto
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cost Reduction ◽  
Immobilized Enzyme ◽  
Proteolytic Enzymes ◽  
Yeast Cells ◽  
Cross Linking ◽  
Soluble Enzyme ◽  
Yeast Suspension ◽  
Yeast Flocculation ◽  
Chitin And Chitosan

Yeast flocculation (Saccharomyces cerevisiae) is one of the most important problems in fuel ethanol production. Yeast flocculation causes operational difficulties and increase in the ethanol cost. Proteolytic enzymes can solve this problem since it does not depend on these changes. The recycling of soluble papain and the immobilization of this enzyme on chitin or chitosan were studied. Some cross-linking agents were evaluated in the action of proteolytic activity of papain. The glutaraldehyde (0.1–10% w·v−1), polyethyleneimine (0.5% v·v−1), and tripolyphosphate (1–10% w·v−1) inactivated the enzyme in this range, respectively. Glutaraldehyde inhibited all treatments of papain immobilization. The chitosan cross-linked with TPP in 5 h of reaction showed the yield of active immobilized enzyme of 15.7% and 6.07% in chitosan treated with 0.1% PEI. Although these immobilizations have been possible, these levels have not been enough to cause deflocculation of yeast cells. Free enzyme was efficient for yeast deflocculation in dosages of 3 to 4 g·L−1. Recycling of soluble papain by centrifugation was effective for 14 cycles with yeast suspension in time perfectly compatible to industrial conditions. The reuse of proteases applied after yeast suspension by additional yeast centrifugation could be an alternative to cost reduction of these enzymes.

A cross-linking strategy provides a new generation of biodegradable and biocompatible cyanoacrylate medical adhesives

2016 ◽  
Vol 4 (23) ◽  
pp. 4147-4155 ◽  
Author(s):  
Liang Xu ◽  
Tao Zhang ◽  
Huajin Dong ◽  
Dazheng Cai ◽  
Han Han ◽  
...  
Keyword(s):  
Cross Linking ◽  
General Strategy ◽  
New Generation

A general strategy provides a new generation of biodegradable and biocompatible cyanoacrylate medical adhesives.

scholarly journals Ductile silica/methacrylate hybrids for bone regeneration

2016 ◽  
Vol 4 (36) ◽  
pp. 6032-6042 ◽  
Author(s):  
Anthony L. B. Maçon ◽  
Siwei Li ◽  
Justin J. Chung ◽  
Amy Nommeots-Nomm ◽  
Anu K. Solanki ◽  
...  
Keyword(s):  
Bone Regeneration ◽  
Class Ii ◽  
Cross Linking ◽  
Scaffold Materials ◽  
New Generation

Hybrids consisting of co-networks of high cross-linking density polymethacrylate and silica (class II hybrid) were synthesised as a potential new generation of scaffold materials.

scholarly journals Cross-Linked Enzyme Aggregates of Naringinase: Novel Biocatalysts for Naringin Hydrolysis

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Maria H. L. Ribeiro ◽  
Marco Rabaça
Keyword(s):  
Polyethylene Glycol ◽  
Ammonium Sulphate ◽  
Mechanical Stability ◽  
Butyl Alcohol ◽  
Cross Linking ◽  
Enzyme Complex ◽  
Food Industries ◽  
Highly Active ◽  
New Generation ◽  
Polyethylene Glycol 6000

Cross-linked enzyme aggregates (CLEAs) have emerged as interesting biocatalyst design for immobilization. These new generation enzyme biocatalysts, CLEAs, in addition to exhibiting good mechanical stability, can be highly active, since they do not include large amounts of foreign particulate nonenzymatic material and may have increased stability. Naringinase (NGase) is an enzyme complex with high potential in pharmaceutical and food industries. In fact, NGase can be used in the biotransformation of steroids, of antibiotics and mainly on glycosides hydrolysis. In this paper, the formation of CLEAs was tried using ammonium sulphate, polyethylene glycol 6000 and tert-butyl alcohol as precipitant agents and glutaraldehyde as cross-linking agent, at different pH, time, and temperature conditions. However, among the precipitant agents tested, only tert-butyl alcohol cross-linked with glutaraldehyde allowed the formation of CLEAs, at pH 4.0 and at temperature between 7 and 10∘C. Different enzyme loadings were tested. The NGase-CLEAs were highly effective in naringin hydrolysis. The operational stability of the NGase-CLEAs aggregates was studied through six successive reutilizations.

Wet Chemical Processing with Megasonics Assist for the Removal of Bumping Process Photomasks

2014 ◽  
Vol 2014 (DPC) ◽  
pp. 001966-001981 ◽  
Author(s):  
Sohn Hong Seong ◽  
John Tracy
Keyword(s):  
Chain Scission ◽  
Cross Linking ◽  
Solvent Exposure ◽  
Major Drawback ◽  
Photoresist Layer ◽  
Advanced Packaging ◽  
Thick Photoresist ◽  
Negative Tone ◽  
Chemical Events ◽  
New Generation

A new generation of negative tone resists by TOK, JSR, and Dow Chemical is gaining momentum in advanced packaging applications. Resist thickness requirements are actually increasing to the 50-100 um range as Cu pillars are adopted to accommodate the tighter pitches required in advanced packaging. In order to form pillars the resist must be thicker to contain the entire bump structure. Thick, negative tone resists are more transparent to exposure light wavelengths than positive tone resists and can be exposed by the lithography process much faster (~1 x 104 cross-linking chemical events are driven by 1 photochemical event vs. 100 – 1000 for positive tone resist).1 Therefore exposure times can be shorter, post-exposure bake steps can be shorter, and delay before or after exposure is not necessary, saving photolithography time and CoO. And, due to more complete cross-linking throughout the resist, the resist mask profiles are truer (from Flack et.al, “A Comparison of New Thick Photoresists for Solder Bumping”, SPIE 2005).1 The major drawback to negative tone resists is that the solvent strip times of the highly cross-linked resist masks are much longer than for positive tone. Flack et.al. noted resist strip times of 5 minutes for two positive resists used in their experiments vs. 50 minutes for the AZ-100nXT negative tone resist, using AZ400T at 80°C (most likely in an immersion tool). Long strip times or special stripping requirements are noted on the data sheets of the other majority suppliers of negative resists as well. Akrion engineers have developed a novel, single-wafer, negative PR strip processes using organic solvents plus Goldfinger megasonics, to provide 30 - 70% reductions in process times and the associated chemical consumption when compared to processes that do not utilize a megasonics assist. The multi-step process can be accomplished in a single process chamber, with each step optimized for time and temperature based on the resist thickness and solvent stripping chemistry used. In the Akrion process, a period of solvent exposure at low wafer spin speed is used initially to begin swelling and dissolving the thick photoresist layer. This is followed by a second solvent exposure step using aggressive frontside megasonic energy to promote polymer chain scission throughout the bulk of the photoresist layer. Following this step A DI water rinse and spin dry step are sufficient to completely remove the solvent, dissolved photoresist and any polymer residues. This paper reviews the development of the Akrion process and several examples of improvement in stripping time and results from work with customers.

scholarly journals Antibody-mediated targeting of α-1,4-glucosidase-albumin polymers to rat hepatocytes A model for enzyme therapy

1981 ◽  
Vol 196 (1) ◽  
pp. 89-93 ◽  
Author(s):  
M J Poznansky ◽  
D Bhardwaj
Keyword(s):  
Glycogen Content ◽  
Rat Hepatocytes ◽  
Cross Linking ◽  
Polymer Complex ◽  
Type Ii ◽  
Enzyme Therapy ◽  
Soluble Enzyme ◽  
Isolated Rat Hepatocytes ◽  
Specific Igg ◽  
Isolated Rat

Chemically cross-linking alpha-1,4-glucosidase, homologous albumin and antibody (immunoglobulin G, IgG) molecules raised against isolated rat hepatocytes yields an active and stable soluble enzyme-polymer complex of mol.wt. approx. 10(6). After intravenous injection, the 125I-labelled complex is seen to be preferentially associated with hepatocytes when compared with labelled free alpha-1,4-glucosidase, enzyme-albumin polymers without IgG or polymer linked to a non-specific IgG molecule, all of which are associated to a much larger extent with the Kupffer cells. The procedure offers several advantages for targeting of enzymes to specific tissues and cells and for the possible lowering of hepatocyte glycogen content in Type II glycogenesis (Pompe's disease).

Influence of Calcium Ions on the Plant Cell Surface: Membrane Fusions and Conformational Changes

1974 ◽  
Vol 32 ◽  
pp. 154-155
Author(s):  
D. James Morré ◽  
Charles E. Bracker ◽  
William J. VanDerWoude
Keyword(s):  
Cell Wall ◽  
Cell Surface ◽  
Conformational Changes ◽  
Calcium Ions ◽  
Surface Membrane ◽  
Carboxyl Groups ◽  
Cross Linking ◽  
Ultrastructural Evidence ◽  
Glycine Max L ◽  
Wall Extensibility

Calcium ions in the concentration range 5-100 mM inhibit auxin-induced cell elongation and wall extensibility of plant stems. Inhibition of wall extensibility requires that the tissue be living; growth inhibition cannot be explained on the basis of cross-linking of carboxyl groups of cell wall uronides by calcium ions. In this study, ultrastructural evidence was sought for an interaction of calcium ions with some component other than the wall at the cell surface of soybean (Glycine max (L.) Merr.) hypocotyls.

Embedding Procedure for Water Swollen Samples

1970 ◽  
Vol 28 ◽  
pp. 504-505
Author(s):  
Ann M. Thomas ◽  
Virginia Shemeley
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ion Exchange ◽  
Structural Changes ◽  
Cross Linking ◽  
Ion Exchange Resins ◽  
Transmission Electron ◽  
First Pass ◽  
Exchange Resins

Those samples which swell rapidly when exposed to water are, at best, difficult to section for transmission electron microscopy. Some materials literally burst out of the embedding block with the first pass by the knife, and even the most rapid cutting cycle produces sections of limited value. Many ion exchange resins swell in water; some undergo irreversible structural changes when dried. We developed our embedding procedure to handle this type of sample, but it should be applicable to many materials that present similar sectioning difficulties.The purpose of our embedding procedure is to build up a cross-linking network throughout the sample, while it is in a water swollen state. Our procedure was suggested to us by the work of Rosenberg, where he mentioned the formation of a tridimensional structure by the polymerization of the GMA biproduct, triglycol dimethacrylate.

Finding the Right Problems: Some HREM Applications to Interfaces

1984 ◽  
Vol 42 ◽  
pp. 376-379
Author(s):  
D. Cherns
Keyword(s):  
Grain Boundaries ◽  
High Resolution Electron Microscopy ◽  
Boundary Structure ◽  
Atomic Structures ◽  
Grain Boundary Structure ◽  
Resolution Electron ◽  
Point To Point ◽  
The Right ◽  
New Generation ◽  
Better Than

The use of high resolution electron microscopy (HREM) to determine the atomic structure of grain boundaries and interfaces is a topic of great current interest. Grain boundary structure has been considered for many years as central to an understanding of the mechanical and transport properties of materials. Some more recent attention has focussed on the atomic structures of metalsemiconductor interfaces which are believed to control electrical properties of contacts. The atomic structures of interfaces in semiconductor or metal multilayers is an area of growing interest for understanding the unusual electrical or mechanical properties which these new materials possess. However, although the point-to-point resolutions of currently available HREMs, ∼2-3Å, appear sufficient to solve many of these problems, few atomic models of grain boundaries and interfaces have been derived. Moreover, with a new generation of 300-400kV instruments promising resolutions in the 1.6-2.0 Å range, and resolutions better than 1.5Å expected from specialist instruments, it is an appropriate time to consider the usefulness of HREM for interface studies.

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