scholarly journals Effect of Concentrated Salts Solutions on the Stability of Immobilized Enzymes: Influence of Inactivation Conditions and Immobilization Protocol

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 968
Author(s):  
Sabrina Ait Braham ◽  
El-Hocine Siar ◽  
Sara Arana-Peña ◽  
Diego Carballares ◽  
Roberto Morellon-Sterling ◽  
...  
Keyword(s):  
Immobilized Enzyme ◽  
Enzyme Stability ◽  
Immobilized Enzymes ◽  
Penicillin G ◽  
Specific Enzyme ◽  
Interfacial Activation ◽  
Agarose Beads ◽  
High Concentrations ◽  
The Stability ◽  
Universal Rule

This paper aims to investigate the effects of some salts (NaCl, (NH4)2SO4 and Na2SO4) at pH 5.0, 7.0 and 9.0 on the stability of 13 different immobilized enzymes: five lipases, three proteases, two glycosidases, and one laccase, penicillin G acylase and catalase. The enzymes were immobilized to prevent their aggregation. Lipases were immobilized via interfacial activation on octyl agarose or on glutaraldehyde-amino agarose beads, proteases on glyoxyl agarose or glutaraldehyde-amino agarose beads. The use of high concentrations of salts usually has some effects on enzyme stability, but the intensity and nature of these effects depends on the inactivation pH, nature and concentration of the salt, enzyme and immobilization protocol. The same salt can be a stabilizing or a destabilizing agent for a specific enzyme depending on its concentration, inactivation pH and immobilization protocol. Using lipases, (NH4)2SO4 generally permits the highest stabilities (although this is not a universal rule), but using the other enzymes this salt is in many instances a destabilizing agent. At pH 9.0, it is more likely to find a salt destabilizing effect than at pH 7.0. Results confirm the difficulty of foreseeing the effect of high concentrations of salts in a specific immobilized enzyme.

scholarly journals Immobilization of Eversa Lipase on Octyl Agarose Beads and Preliminary Characterization of Stability and Activity Features

Catalysts ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 511 ◽  
Author(s):  
Sara Arana-Peña ◽  
Yuliya Lokha ◽  
Roberto Fernández-Lafuente
Keyword(s):  
Immobilized Enzyme ◽  
Biodiesel Production ◽  
Free Form ◽  
Enzyme Specificity ◽  
Agarose Beads ◽  
The Stability ◽  
Isoform B ◽  
First Time ◽  
Commercial Lipase

Eversa is an enzyme recently launched by Novozymes to be used in a free form as biocatalyst in biodiesel production. This paper shows for first time the immobilization of Eversa (a commercial lipase) on octyl and aminated agarose beads and the comparison of the enzyme properties to those of the most used lipase, the isoform B from Candida antarctica (CALB) immobilized on octyl agarose beads. Immobilization on octyl and aminated supports of Eversa has not had a significant effect on enzyme activity versus p-nitrophenyl butyrate (pNPB) under standard conditions (pH 7), but immobilization on octyl agarose beads greatly enhanced the stability of the enzyme under all studied conditions, much more than immobilization on aminated support. Octyl-Eversa was much more stable than octyl-CALB at pH 9, but it was less stable at pH 5. In the presence of 90% acetonitrile or dioxane, octyl-Eversa maintained the activity (even increased the activity) after 45 days of incubation in a similar way to octyl-CALB, but in 90% of methanol, results are much worse, and octyl-CALB became much more stable than Eversa. Coating with PEI has not a clear effect on octyl-Eversa stability, although it affected enzyme specificity and activity response to the changes in the pH. Eversa immobilized octyl supports was more active than CALB versus triacetin or pNPB, but much less active versus methyl mandelate esters. On the other hand, Eversa specificity and response to changes in the medium were greatly modulated by the immobilization protocol or by the coating of the immobilized enzyme with PEI. Thus, Eversa may be a promising biocatalyst for many processes different to the biodiesel production and its properties may be greatly improved following a suitable immobilization protocol, and in some cases is more stable and active than CALB.

scholarly journals Multi-Combilipases: Co-Immobilizing Lipases with Very Different Stabilities Combining Immobilization via Interfacial Activation and Ion Exchange. The Reuse of the Most Stable Co-Immobilized Enzymes after Inactivation of the Least Stable Ones

Catalysts ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1207
Author(s):  
Sara Arana-Peña ◽  
Diego Carballares ◽  
Vicente Cortés Corberan ◽  
Roberto Fernandez-Lafuente
Keyword(s):  
Ammonium Sulfate ◽  
Rhizomucor Miehei ◽  
Immobilized Enzymes ◽  
The Other ◽  
Thermomyces Lanuginosus ◽  
Vinyl Sulfone ◽  
Interfacial Activation ◽  
Agarose Beads ◽  
Immobilized Biocatalyst ◽  
Lecitase Ultra

The lipases A and B from Candida antarctica (CALA and CALB), Thermomyces lanuginosus (TLL) or Rhizomucor miehei (RML), and the commercial and artificial phospholipase Lecitase ultra (LEU) may be co-immobilized on octyl agarose beads. However, LEU and RML became almost fully inactivated under conditions where CALA, CALB and TLL retained full activity. This means that, to have a five components co-immobilized combi-lipase, we should discard 3 fully active and immobilized enzymes when the other two enzymes are inactivated. To solve this situation, CALA, CALB and TLL have been co-immobilized on octyl-vinyl sulfone agarose beads, coated with polyethylenimine (PEI) and the least stable enzymes, RML and LEU have been co-immobilized over these immobilized enzymes. The coating with PEI is even favorable for the activity of the immobilized enzymes. It was checked that RML and LEU could be released from the enzyme-PEI coated biocatalyst, although this also produced some release of the PEI. That way, a protocol was developed to co-immobilize the five enzymes, in a way that the most stable could be reused after the inactivation of the least stable ones. After RML and LEU inactivation, the combi-biocatalysts were incubated in 0.5 M of ammonium sulfate to release the inactivated enzymes, incubated again with PEI and a new RML and LEU batch could be immobilized, maintaining the activity of the three most stable enzymes for at least five cycles of incubation at pH 7.0 and 60 °C for 3 h, incubation on ammonium sulfate, incubation in PEI and co-immobilization of new enzymes. The effect of the order of co-immobilization of the different enzymes on the co-immobilized biocatalyst activity was also investigated using different substrates, finding that when the most active enzyme versus one substrate was immobilized first (nearer to the surface of the particle), the activity was higher than when this enzyme was co-immobilized last (nearer to the particle core).

scholarly journals Reuse of Lipase from Pseudomonas fluorescens via Its Step-by-Step Coimmobilization on Glyoxyl-Octyl Agarose Beads with Least Stable Lipases

Catalysts ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 487 ◽  
Author(s):  
Nathalia Rios ◽  
Sara Arana-Peña ◽  
Carmen Mendez-Sanchez ◽  
Claudia Ortiz ◽  
Luciana Gonçalves ◽  
...  
Keyword(s):  
Pseudomonas Fluorescens ◽  
Rhizomucor Miehei ◽  
The Other ◽  
Initial Activity ◽  
Interfacial Activation ◽  
Full Activity ◽  
Agarose Beads ◽  
Lecitase Ultra ◽  
The Stability ◽  
Triton X

Coimmobilization of lipases may be interesting in many uses, but this means that the stability of the least stable enzyme determines the stability of the full combilipase. Here, we propose a strategy that permits the reuse the most stable enzyme. Lecitase Ultra (LU) (a phospholipase) and the lipases from Rhizomucor miehei (RML) and from Pseudomonas fluorescens (PFL) were immobilized on octyl agarose, and their stabilities were studied under a broad range of conditions. Immobilized PFL was found to be the most stable enzyme under all condition ranges studied. Furthermore, in many cases it maintained full activity, while the other enzymes lost more than 50% of their initial activity. To coimmobilize these enzymes without discarding fully active PFL when LU or RML had been inactivated, PFL was covalently immobilized on glyoxyl-agarose beads. After biocatalysts reduction, the other enzyme was coimmobilized just by interfacial activation. After checking that glyoxyl-octyl-PFL was stable in 4% Triton X-100, the biocatalysts of PFL coimmobilized with LU or RML were submitted to inactivation under different conditions. Then, the inactivated least stable coimmobilized enzyme was desorbed (using 4% detergent) and a new enzyme reloading (using in some instances RML and in some others employing LU) was performed. The initial activity of immobilized PFL was maintained intact for several of these cycles. This shows the great potential of this lipase coimmobilization strategy.

-CHYMOTRYPSIN IMMOBILIZED ENZYME: PHYSICAL, ACTIVITY & STABILITY PROPERTIES

2015 ◽  
Vol 76 (1) ◽  
Author(s):  
Mohd Hakimi Nazir ◽  
Norzita Ngadi
Keyword(s):  
Physical Properties ◽  
Immobilized Enzyme ◽  
Enzyme Stability ◽  
Sample Solution ◽  
Bet Surface Area ◽  
Adsorption Activity ◽  
Hy Zeolite ◽  
Isotherm Adsorption ◽  
The Stability ◽  
Stability Results

In this study, α-chymotrypsin enzyme was used as a substrate while micropore Y-zeolite, which is HY, USY and NaY as a support. The purpose of this study was to compare the physical properties of zeolite and immobilization of enzyme with zeolite.  The characteristics such as BET surface area, isotherm adsorption, BJH adsorption, pore size, t-plot and pore volume have been studied. Furthermore, a comparison has been conducted between immobilized and mobile enzyme for their ability to adsorb hydrolysate at λ=410 nm.  The stability of the immobilized enzyme was also determined by varying the parameters of phosphate and tris-chloride buffer and loading of sample solution. Based on the result obtained, HY zeolite has the best physical properties compared to USY and NaY zeolite.  Besides that, immobilized enzyme gave higher hydrolysate adsorption activity than the free enzyme. Stability results showed that pH of phosphate and tris-chloride buffer and amount of sample solution play an important role in obtaining the stable immobilized enzyme.   

A comparative analysis on different enzyme immobilization nanomaterials: Progress, constraints, and recent trends

2020 ◽  
Vol 28 ◽  
Author(s):  
Fatemeh Borzouee ◽  
Jaleh Varshosaz ◽  
Reza Ahangari Cohan ◽  
Dariush Norouzian ◽  
Razieh Taghizadeh Pirposhteh
Keyword(s):  
Enzyme Immobilization ◽  
Immobilized Enzyme ◽  
Enzyme Stability ◽  
Recent Decade ◽  
Immobilized Enzymes ◽  
Industrial Applications ◽  
Mass Transfer Limitation ◽  
The Matrix ◽  
Main Components ◽  
Immobilization Techniques

Abstract:: Immobilization techniques have been popularly used to preserve the operational stability of the enzymes for industrial applications. The three main components of an immobilized enzyme system are the enzyme, the matrix/support, and the technique of immobilization. So far different supports have been developed to improve the efficiency of the immobilized enzymes. But in the recent decade, nanotechnology has been considerable research interest in the field of immobilized enzyme carriers. The materials at the nano-scale due to their unique physicochemical properties including; specific surface area, mass transfer limitation, and effective enzyme loading, are considered as interesting matrices for enzyme immobilization. This review describes techniques employed to immobilize enzymes and provides an integrated focus on the most common nanoparticles for enzyme conjugation. Additionally, the pros and cons of nanoparticles as immobilization matrices are also discussed. Depending on the type of enzyme and its application, in this review, the researchers are directed to select an appropriate method and support for enzyme immobilization in terms of enzyme stability and functionality.

scholarly journals THE RATE OF BACTERICIDAL ACTION OF PENICILLIN IN VITRO AS A FUNCTION OF ITS CONCENTRATION, AND ITS PARADOXICALLY REDUCED ACTIVITY AT HIGH CONCENTRATIONS AGAINST CERTAIN ORGANISMS

1948 ◽  
Vol 88 (1) ◽  
pp. 99-131 ◽  
Author(s):  
Harry Eagle ◽  
A. D. Musselman
Keyword(s):  
Bacterial Species ◽  
Fold Increase ◽  
Bactericidal Effect ◽  
Penicillin G ◽  
Bacterial Suspension ◽  
Maximal Effect ◽  
Maximal Rate ◽  
Effective Level ◽  
High Concentrations

1. The concentrations of penicillin G which (a) reduced the net rate of multiplication, (b) exerted a net bactericidal effect, and (c) killed the organisms at a maximal rate, have been defined for a total of 41 strains of α- and ß-hemolytic streptococci, Staphylococcus aureus and Staphylococcus albus, Diplococcus pneumoniae, and the Reiter treponoma. 2. The concentration which killed the organisms at a maximal rate was 2 to 20 times the minimal effective level ("sensitivity" as ordinarily defined). With some organisms, even a 32,000-fold increase beyond this maximally effective level did not further increase the rate of its bactericidal effect. However, with approximately half the strains here studied (all 4 strains of group B ß-hemolytic streptococci, 4 of 5 group C strains, 5 of 7 strains of Streptococcus fecalis, 2 of 4 other α-hemolytic streptococci, and 4 of 9 strains of staphylococci), when the concentration of penicillin was increased beyond that optimal level, the rate at which the organisms died was paradoxically reduced rather than increased, so that the maximal effect was obtained only within a relatively narrow optimal zone. 3. There were marked differences between bacterial species, and occasionally between different strains of the same species, not only with respect to the effective concentrations of penicillin, but also with respect to the maximal rate at which they could be killed by the drug in any concentration. Although there was a rough correlation between these two factors, there were many exceptions; individual strains affected only by high concentrations of penicillin might nevertheless be killed rapidly, while strains sensitive to minute concentrations might be killed only slowly. 4. Within the same bacterial suspension, individual organisms varied only to a minor degree with respect to the effective concentrations of penicillin. They varied strikingly, however, in their resistance to penicillin as measured by the times required to kill varying proportions of the cells.

scholarly journals The potentional of plants to cleanup metals from an old landfill site

2017 ◽  
Author(s):  
Yahya Jani ◽  
Charlotte Marchand ◽  
William Hogland
Keyword(s):  
Contaminated Soils ◽  
Hazardous Materials ◽  
Average Concentration ◽  
Soil Samples ◽  
Landfill Site ◽  
Group Company ◽  
Timothy Grass ◽  
Xrf Scanning ◽  
High Concentrations ◽  
The Stability

Old landfill sites contain different hazardous materials like heavy metals which have the ability to affects the entire environment. These places are sometimes covered by plants to increase the stability of the soil and to reduce the effects of erosion. 15 soil samples (3 samples from each place) and 5-7 timothy-grass (Phleum pretense) plants from 5 different places were taken from an old landfill place in an active landfill site in Högbytorp /Sweden owned by Ragn-sells Group Company. XRF scanning was used to analyze the metal content of soil samples and of plants. High concentrations of metals were detected in the soil samples like Fe with an average of about 25000 ppm, Mn about 250 ppm and 2800 ppm of Ti. The plants results showed an average concentration of Fe in the shoots about 730 ppm, Mn about 60 ppm and Ti about 1760 ppm. On the other hand, the roots results showed an average concentration of about 10 000 ppm of Fe, about 160 ppm of Mn and 2200 ppm of Ti. These results gave the indication that the Timothy-grass has the ability to extract metals from contaminated soils and can help to cleanup these soils.

Selection for soyabeans with high and environmentally stable lutein concentrations

2014 ◽  
Vol 12 (S1) ◽  
pp. S12-S16 ◽  
Author(s):  
Krishna Hari Dhakal ◽  
Myoung-Gun Choung ◽  
Young-Sun Hwang ◽  
Felix B. Fritschi ◽  
J. Grover Shannon ◽  
...  
Keyword(s):  
Human Health ◽  
High Stability ◽  
Planting Dates ◽  
Early Maturity ◽  
Breeding Objective ◽  
Late Maturity ◽  
Selection For ◽  
High Concentrations ◽  
The Stability ◽  
Nutritional Benefits

Lutein has significant nutritional benefits for human health. Therefore, enhancing soybean lutein concentrations is an important breeding objective. However, selection for soybeans with high and environmentally stable lutein concentrations has been limited. The objectives of this study were to select soybeans with high seed lutein concentrations and to determine the stability of lutein concentrations across environments. A total of 314 genotypes were screened and 18 genotypes with high lutein concentrations and five genotypes with low lutein concentrations were selected for further examination. These 23 genotypes and two check varieties were evaluated under six environments (two planting dates for 2 years at one location and two planting dates for 1 year at another location). Lutein concentrations were influenced by genotype, environment and genotype × environment interactions. Genotypes with late maturity and low lutein concentrations were more stable than those with early maturity and high concentrations. Early (May) planting resulted in greater lutein concentrations than late (June) planting. Among the genotypes evaluated, PI603423B (7.7 μg/g) and PI89772 (5.8 μg/g) had the greatest mean lutein concentrations and exhibited medium and high stability across the six environments, respectively. Thus, these genotypes may be useful for breeding soybeans with high and stable seed lutein concentrations.

Tailoring surface properties of functionalized graphene papers aiming to enzyme immobilization

2021 ◽  
Author(s):  
Jéssica Luzardo ◽  
Douglas Aguiar ◽  
Alexander Silva ◽  
Sanair Oliveira ◽  
Braulio Archanjo ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Photoelectron Spectroscopy ◽  
Enzyme Stability ◽  
Immobilized Enzymes ◽  
Free Enzyme ◽  
X Ray ◽  
Force Microscopy ◽  
Enzyme Solution ◽  
Atomic Force ◽  
Composition And Structure

The use of enzymes as catalysts requires recovery and reuse to make the process viable. Enzymatic immobilization changes enzyme stability, activity, and specificity. It is very important to explore new substrates for immobilization with appropriate composition and structure to improve the efficiency of the immobilized enzymes. This work explores the use of two different graphene oxide papers, one produced by oxidation route (GO) and the other by electrochemical synthesis (EG), aiming for β-galactosidase immobilization. The chemical and structural properties of these two papers were characterized by Raman spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction. Atomic force microscopy images showed that EG paper ensured more efficient immobilization of the enzymes on the surface of the paper. Cyclic voltammetry was used to monitor the reaction of conversion of lactose to glucose in the free enzyme solution and graphene paper immobilized enzyme solutions. The cyclic voltammetry analysis showed that immobilized enzymes on GO paper showed an improvement in the activity of β-galactose when compared to free enzyme solution, as well as enzyme immobilized on a glassy carbon electrode.

The chemical stability of mendipite, diaboleïte, chloroxiphite, and cumengéite, and their relationships to other secondary lead(II) minerals

1980 ◽  
Vol 43 (331) ◽  
pp. 901-904 ◽  
Author(s):  
D. Alun Humphreys ◽  
John H. Thomas ◽  
Peter A. Williams ◽  
Robert F. Symes
Keyword(s):  
Chloride Ion ◽  
Stability Diagram ◽  
Chloride Ions ◽  
Ion Concentration ◽  
Stability Field ◽  
Cupric Ion ◽  
Free Energy Of Formation ◽  
High Concentrations ◽  
The Stability ◽  
Ph Range

SummaryThe chemical stabilities of mendipite, Pb3O2Cl2, diaboleïte, Pb2CuCl2(OH)4, chloroxiphite, Pb3CuCl2O2(OH)2, and cumengéite, Pb19Cu24Cl42 (OH)44, have been determined in aqueous solution at 298.2 K. Values of standard Gibbs free energy of formation, ΔGf°, for the four minerals are −740, −1160, −1129, and −15163±20 kJ mol−1 respectively. These values have been used to construct the stability diagram shown in fig. I which illustrates their relationships to each other and to the minerals cotunnite, PbCl2, paralaurionite, PbOHCl, and litharge, PbO. This diagram shows that mendipite occupies a large stability field and should readily form from cold, aqueous, mineralizing solutions containing variable amounts of lead and chloride ions, and over a broad pH range. The formation of paralaurionite and of cotunnite requires a considerable increase in chloride ion concentration, although paralaurionite can crystallize under much less extreme conditions than cotunnite. The encroachment of the copper minerals on to the stability fields of those mineral phases containing lead(II) only is significant even at very low relative activities of cupric ion. Chloroxiphite has a large stability field, and at given concentrations of cupric ion, diaboleïte is stable at relatively high aCl−. Cumengéite will only form at high concentrations of chloride ion.

Sign in / Sign up

Export Citation Format

Share Document