Laccase immobilization via cross-linked aggregate preparation: Characterization, thermodynamic/kinetic properties and application in removal of bisphenol A from solutions

Mapping Intimacies ◽

10.21203/rs.3.rs-267600/v1 ◽

2021 ◽

Author(s):

Adedeji Ademakinwa

Keyword(s):

Bisphenol A ◽

Kinetic Parameters ◽

Heat Denaturation ◽

Heat Inactivation ◽

Inactivation Kinetics ◽

Kinetic Properties ◽

Optimum Conditions ◽

The Stability ◽

Laccase Immobilization ◽

Optimized Conditions

Abstract Fungal laccase from Aureobasidium pullulans was immobilized via cross-linked enzyme aggregate (CLEA) preparation under statistically optimized conditions. The stability of the CLEA to heat inactivation was studied via investigation of its thermodynamic and kinetic parameters. The immobilized enzyme was then deployed in the biodegradation of a bisphenol-A (BPA). The optimum conditions for CLEA preparation resulting in the highest immobilization yield were ammonium sulphate (60% v/v), glutaraldehyde (30 mM), pH (4.5), time (6 h) and temperature (55ºC). The CLEA retained about 51% of its activity after eight catalytic cycles. The optimum pH and temperature of the laccase CLEA were 5.5 and 60ºC respectively. The SEM indicated that the laccase CLEA was type II (unstructured). The data obtained from the heat inactivation kinetics and thermodynamic characterization indicated that the CLEA was stable to heat denaturation than the free enzyme. The kinetic parameters obtained for the CLEA with ABTS as substrate were 101.3 µM, 2.94 µmols-1mg-1 and 0.03 dm3s-1mg-1 for the Km, Kcat and Kcat/Km respectively. The optimum conditions for BPA biodegradation using the CLEA were temperature (55ºC), time (2 h), CLEA (1.0 mg) and BPA concentration (40 mg/L). After the 7th cycle, laccase CLEA retained about 63 ± 2.3% biodegradation efficiency. A heat-resistant laccase CLEA was able to remove BPA from solutions under statistically optimized conditions. The laccase CLEA has properties for other futuristic applications.

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Kinetics of alkaline phosphatase and lactoperoxidase inactivation, and of β-lactoglobulin denaturation in milk with different fat content

Journal of Dairy Research ◽

10.1017/s0022029902005721 ◽

2002 ◽

Vol 69 (4) ◽

pp. 541-553 ◽

Cited By ~ 24

Author(s):

WENDIE L. CLAEYS ◽

ANN M. VAN LOEY ◽

MARC E. HENDRICKX

Keyword(s):

Alkaline Phosphatase ◽

Milk Fat ◽

Fat Content ◽

Heat Processing ◽

Heat Denaturation ◽

Heat Inactivation ◽

Inactivation Kinetics ◽

Denaturation Kinetics ◽

Skimmed Milk ◽

Β Lactoglobulin

In the context of identifying intrinsic time temperature integrators (TTIs) for evaluating heat processing of milk, the extent to which milk fat content has an effect on alkaline phosphatase (ALP) and lactoperoxidase (Lpo) inactivation and on β-lactoglobulin (β-lg) denaturation kinetics was studied. Inactivation and denaturation kinetics were analysed in whole, semi-skimmed and skimmed milk. In previous experiments (isothermal and non-isothermal heating conditions), heat inactivation of ALP and Lpo and heat denaturation of β-lg were found to follow first order kinetics. This allowed experimental design to be simplified. Data analysis was performed by non-linear regression and results were evaluated by construction of joint confidence regions. The possible effect of milk fat was illustrated by temperature time tolerance (TTT-) diagrams. Although initial ALP activity was lower in skimmed milk compared with semi-skimmed or whole milk, kinetics were comparable and fat content did not seem to substantially affect the ALP test result for pasteurized milk. Unlike ALP, Lpo inactivation and β-lg denaturation kinetics differed significantly in milk with different fat content. Differences between Lpo inactivation kinetics were relatively small and acceptable in the context of quantifying the process impact. Denaturation of β-lg, on the other hand, seemed to be enhanced at higher milk fat content (>72 °C).

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DNA Genome Size Affects the Stability of the Adenovirus Virion

Journal of Virology ◽

10.1128/jvi.01644-08 ◽

2008 ◽

Vol 83 (4) ◽

pp. 2025-2028 ◽

Cited By ~ 23

Author(s):

Adam C. Smith ◽

Kathy L. Poulin ◽

Robin J. Parks

Keyword(s):

Genome Size ◽

Critical Role ◽

Heat Stability ◽

Helper Virus ◽

Heat Inactivation ◽

Similar Relationship ◽

Viral Dna ◽

A Genome ◽

The Stability ◽

Replication Defective Adenovirus

ABSTRACT Replication-defective adenovirus (Ad) vectors can vary considerably in genome length, but whether this affects virion stability has not been investigated. Helper-dependent Ad vectors with a genome size of ∼30 kb were 100-fold more sensitive to heat inactivation than their parental helper virus (>36 kb), and increasing the genome size of the vector significantly improved heat stability. A similar relationship between genome size and stability existed for Ad with early region 1 deleted. Loss of infectivity was due to release of vertex proteins, followed by disintegration of the capsid. Thus, not only does the viral DNA encode all of the heritable information essential for virus replication, it also plays a critical role in maintaining capsid strength and integrity.

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Influence of rapid changes in cytosolic pH on oxidative phosphorylation in skeletal muscle: theoretical studies

Biochemical Journal ◽

10.1042/bj20020031 ◽

2002 ◽

Vol 365 (1) ◽

pp. 249-258 ◽

Cited By ~ 10

Author(s):

Bernard KORZENIEWSKI ◽

Jerzy A. ZOLADZ

Keyword(s):

Skeletal Muscle ◽

Creatine Kinase ◽

Oxidative Phosphorylation ◽

Kinetic Properties ◽

Main Role ◽

Anaerobic Glycolysis ◽

Cytosolic Ph ◽

Intensive Exercise ◽

Proton Production ◽

The Stability

Cytosolic pH in skeletal muscle may vary significantly because of proton production/consumption by creatine kinase and/or proton production by anaerobic glycolysis. A computer model of oxidative phosphorylation in intact skeletal muscle developed previously was used to study the kinetic effect of these variations on the oxidative phosphorylation system. Two kinds of influence were analysed: (i) via the change in pH across the inner mitochondrial membrane and (ii) via the shift in the equilibrium of the creatine kinase-catalysed reaction. Our simulations suggest that cytosolic pH has essentially no impact on the steady-state fluxes and most metabolite concentrations. On the other hand, rapid acidification/alkalization of cytosol causes a transient decrease/increase in the respiration rate. Furthermore, changes in pH seem to affect significantly the kinetic properties of transition between resting state and active state. An increase in pH brought about by proton consumption by creatine kinase at the onset of exercise lengthens the transition time. At intensive exercise levels this pH increase could lead to loss of the stability of the system, if not compensated by glycolytic H+ production. Thus our theoretical results stress the importance of processes/mechanisms that buffer/compensate for changes in cytosolic proton concentration. In particular, we suggest that the second main role of anaerobic glycolysis, apart from additional ATP supply, may be maintaining the stability of the system at intensive exercise.

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Treatment of oilfield wastewater by combined process of micro-electrolysis, Fenton oxidation and coagulation

Water Science & Technology ◽

10.2166/wst.2017.486 ◽

2017 ◽

Vol 76 (12) ◽

pp. 3278-3288 ◽

Cited By ~ 3

Author(s):

Zhenchao Zhang

Keyword(s):

Reaction Time ◽

Removal Efficiency ◽

Treatment Process ◽

Cod Removal ◽

Fenton Oxidation ◽

Oily Wastewater ◽

Optimum Conditions ◽

Combined Process ◽

Cod Removal Efficiency ◽

Optimized Conditions

Abstract In this study, a combined process was developed that included micro-electrolysis, Fenton oxidation and coagulation to treat oilfield fracturing wastewater. Micro-electrolysis and Fenton oxidation were applied to reduce chemical oxygen demand (COD) organic load and to enhance organic components gradability, respectively. Orthogonal experiment were employed to investigate the influence factors of micro-electrolysis and Fenton oxidation on COD removal efficiency. For micro-electrolysis, the optimum conditions were: pH, 3; iron-carbon dosage, 50 mg/L; mass ratio of iron-carbon, 2:3; reaction time, 60 min. For Fenton oxidation, a total reaction time of 90 min, a H2O2 dosage of 12 mg/L, with a H2O2/Fe2+ mole ratio of 30, pH of 3 were selected to achieve optimum oxidation. The optimum conditions in coagulation process: pH, cationic polyacrylamide dosage, mixing speed and time is 4.3, 2 mg/L, 150 rpm and 30 s, respectively. In the continuous treatment process under optimized conditions, the COD of oily wastewater fell 56.95%, 46.23%, 30.67%, respectively, from last stage and the total COD removal efficiency reached 83.94% (from 4,314 to 693 mg/L). In the overall treatment process under optimized conditions, the COD of oily wastewater was reduced from 4,314 to 637 mg/L, and the COD removal efficiency reached 85.23%. The contribution of each stage is 68.45% (micro-electrolysis), 24.07% (Fenton oxidation), 7.48% (coagulation), respectively. Micro-electrolysis is the uppermost influencing process on COD removal. Compared with the COD removal efficiency of three processes on raw wastewater under optimized conditions: the COD removal efficiency of single micro-electrolysis, single Fenton oxidation, single coagulation is 58.34%, 44.88% and 39.72%, respectively. Experiments proved the effect of combined process is marvelous and the overall water quality of the final effluent could meet the class III national wastewater discharge standard of petrochemical industry of China (GB8978-1996).

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Purification to homogeneity and characterization of nonproteolyzed potato (Solanum tuberosum) tuber hexokinase 1

Botany ◽

10.1139/b11-016 ◽

2011 ◽

Vol 89 (5) ◽

pp. 289-299 ◽

Cited By ~ 3

Author(s):

Marie-Claude Moisan ◽

Jean Rivoal

Keyword(s):

Solanum Tuberosum ◽

Specific Activity ◽

Solanum Tuberosum L ◽

Extraction Procedure ◽

Hydrophobic Interaction Chromatography ◽

Solanum Chacoense ◽

Kinetic Properties ◽

Chromatographic Separations ◽

The Stability ◽

Fast Flow

We have developed an extraction procedure that improves the stability of potato ( Solanum tuberosum L.) tuber hexokinase (HK) after extraction. Using this protocol, we showed that at least four HK isoforms are present in this tissue, and they can be separated by hydrophobic-interaction chromatography on a butyl-Sepharose™ 4 Fast Flow column. One of the main HK isoforms was purified to homogeneity using further chromatographic separations on red dye, DEAE Fractogel, hydroxyapatite, cibacron blue, and MonoQ matrices. HK-specific activity of this fraction (10.2 U·mg protein–1) corresponds to an enrichment of more than 5500-fold, with a yield of 0.9%. This is the highest reported HK-specific activity from a plant source. The purified enzyme consisted of a monomer with a subunit apparent Mr of 51 kDa when analyzed by SDS–PAGE. This polypeptide was recognized by affinity-purified anti- Solanum chacoense Bitt. recombinant HK IgGs. The protein was digested with trypsin and its digestion products were subjected to MS – MS sequencing after HPLC separation. The sequences of these tryptic peptides matched the predicted coding sequence of the S. tuberosum HK1 gene with a coverage of 57%. Examination of the kinetic properties of the purified protein HK1 indicates that it may be regulated by the internal O2 concentration of the tuber because of its sensitivity to acidic pHs and inhibition by ADP.

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Biogas Production from Combined Irish Potato and Poultry Wastes: Optimization and Kinetic Studies

International Journal of Engineering & Technology ◽

10.14419/ijet.v7i3.36.29206 ◽

2018 ◽

Vol 7 (3.36) ◽

pp. 170

Author(s):

Umar M. Ibrahim ◽

Saeed I. Ahmed ◽

Babagana Gutti ◽

Idris M. Muhammad ◽

Usman D. Hamza ◽

...

Keyword(s):

Anaerobic Digestion ◽

Kinetic Parameters ◽

Ph Value ◽

Biogas Production ◽

Irish Potato ◽

Coefficient Of Determination ◽

Optimum Conditions ◽

Biogas Yield ◽

Potato Waste ◽

Initial Ph

The combination of Irish potato waste (IPW) and poultry waste (PW) can form a synergy resulting into an effective substrate for a better biogas production due to some materials they contain. In this work, optimization and kinetic study of biogas production from anaerobic digestion of IPW and PW was investigated. Response surface methodology (RSM) was applied to optimize conditions such as initial pH, solids concentrations and waste ratios. The anaerobic digestion of the two wastes was carried out in the mesophilic condition and Box-Behnken design (BBD) was used to develop and analyze a predictive model which describes the biogas yield. The results revealed that there is a good fit between the experimental and the predicted biogas yield as revealed by the coefficient of determination (R2) value of 97.93%. Optimization using quadratic RSM predicts biogas yield of 19.75% at the optimal conditions of initial pH value 7.28, solids concentration (w/v) 9.85% and waste ratio (IPW:PW) 45:55%. The reaction was observed to have followed a first order kinetics having R2 and relative squared error (RSE) values of 90.61 and 9.63% respectively. Kinetic parameters, such as rate constant and half-life of the biogas yield were evaluated at optimum conditions to be 0.0392 day-1 and 17.68 days respectively. The optimum conditions and kinetic parameters generated from this research can be used to design real bio-digesters, monitor substrate concentrations, simulate biochemical processes and predict performance of bio-digesters using IPW and PW as substrate.

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Effect of Modified Kiln Dust and a Cationic Surfactant on the Removal of Aromatic and Heavy Metal Compounds from Fuels

Oriental Journal Of Chemistry ◽

10.13005/ojc/350505 ◽

2019 ◽

Vol 35 (5) ◽

pp. 1508-1513

Author(s):

Noura Yahya El Mehbad

Keyword(s):

Heavy Metals ◽

Cationic Surfactant ◽

Oil Quality ◽

Cement Kiln ◽

Polar Molecules ◽

Optimum Conditions ◽

Metal Compounds ◽

Before And After ◽

The Stability ◽

Kiln Dust

This paper aims to investigate removal of aromatic and heavy metals compounds from fuels using cement kiln dust, and a cationic surfactant. The effect of a cationic surfactant and the composition of kiln dust on the stability of fuel was studied. The optimum conditions of adsorption were investigated. The stability of fuels was improved after adsorption because of the absorption of heavy metals, which act as catalysts. The concentrations of kiln dust and additives are effective for the absorption of heteroatoms of polar and nonpolar molecules. The addition of different concentrations of the cationic surfactant to kiln dust enhances the removal of polar molecules in fuel. The relation between the efficiency of the cationic surfactant and the enhanced removal of polar molecules was established. This study suggests a new mechanism to remove polar molecules according to the structure of the additive. Several parameters that affect the performance of the removal process were investigated under all optimum conditions. A complete chemical analysis of the fuels before and after treatment was performed, and the stability of the fuel was evaluated at different conditions. The prepared additive could enhance the oil quality and is environmentally safe. The adsorption behaviour of kiln dust was investigated to find a new mechanism of its efficiency. The results confirm the role of the cationic surfactant in the purification of fuels and the effectiveness of kiln dust in improving the stability of fuels, which depend on the concentration of the cationic surfactant and the nature of the kiln dust.

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A differential scanning calorimetric study of the stability of egg white to heat denaturation

Journal of the Science of Food and Agriculture ◽

10.1002/jsfa.2740260109 ◽

1975 ◽

Vol 26 (1) ◽

pp. 73-83 ◽

Cited By ~ 161

Author(s):

John W. Donovan ◽

Carol J. Mapes ◽

John Gorton Davis ◽

John A. Garibaldi

Keyword(s):

Egg White ◽

Heat Denaturation ◽

Differential Scanning Calorimetric ◽

Calorimetric Study ◽

The Stability

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Mechanism of activation of renal Na+-K+-ATPase in the rat: effects of potassium loading

AJP Renal Physiology ◽

10.1152/ajprenal.1980.238.4.f315 ◽

1980 ◽

Vol 238 (4) ◽

pp. F315-F323 ◽

Cited By ~ 1

Author(s):

H. J. Rodriguez ◽

W. C. Hogan ◽

R. N. Hellman ◽

S. Klahr

Keyword(s):

Thyroid Hormones ◽

Kinetic Parameters ◽

Enzyme Induction ◽

Specific Activity ◽

Rat Kidney ◽

Enzymatic Reaction ◽

Kinetic Properties ◽

Renal Growth ◽

Hill Coefficients ◽

Potassium Loading

The mechanism of activation of Na+-K+-ATPase after chronic potassium loading has been investigated in the rat kidney. Potassium loading stimulated the specific activity of Na+-K+-ATPase in the cortex and medulla of the kidney. This effect was not accompanied by a generalized increase in the cellular contents of RNA and proteins and could not be accounted for by an effect of potassium loading on renal growth. Enzyme induction does not appear to be mediated by changes in the endogenous levels of glucocorticoid or thyroid hormones. Evidence obtained from investigation of the partial reactions (Pi intermediate, ouabain-sensitive pNPPase) of the Na+-K+-ATPase enzymatic reaction is consistent with the interpretation that chronic potassium loading in the rat increases the number of enzyme units (Na+ pumps) in the cortex of the kidney. Analysis of the kinetic parameters (Km, K1/2, Vmax, Hill coefficients) of the enzymatic reaction indicates that K+ loading has little or no effect on the kinetic properties (affinity, cooperativity) of the stimulated transport enzyme.

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