scholarly journals Production of Trans-Cinnamic Acid by Immobilization of the Bambusa oldhamii BoPAL1 and BoPAL2 Phenylalanine Ammonia-Lyases on Electrospun Nanofibers

2021 ◽  
Vol 22 (20) ◽  
pp. 11184
Author(s):  
Pei-Yu Hong ◽  
Yi-Hao Huang ◽  
GiGi Chin Wen Lim ◽  
Yen-Po Chen ◽  
Che-Jen Hsiao ◽  
...  
Keyword(s):  
Response Surface ◽  
Cinnamic Acid ◽  
Catalytic Efficiency ◽  
Electrospun Nanofibers ◽  
Industrial Applications ◽  
Cross Linking ◽  
Pal Activity ◽  
Surface Models ◽  
Dextran Polyaldehyde ◽  
Bambusa Oldhamii

Phenylalanine ammonia-lyase (PAL) catalyzes the nonoxidative deamination of phenylalanine to yield trans-cinnamic acid and ammonia. Recombinant Bambusa oldhamii BoPAL1/2 proteins were immobilized onto electrospun nanofibers by dextran polyaldehyde as a cross-linking agent. A central composite design (CCD)-response surface methodology (RSM) was utilized to optimize the electrospinning parameters. Escherichia coli expressed eBoPAL2 exhibited the highest catalytic efficiency among four enzymes. The optimum conditions for fabricating nanofibers were determined as follows: flow rate of 0.10 mL/h, voltage of 13.8 kV, and distance of 13 cm. The response surface models were used to obtain the smaller the fiber diameters as well as the highest PAL activity in the enzyme immobilization. Compared with free BoPALs, immobilized BoPALs can be reused for at least 6 consecutive cycles. The remained activity of the immobilized BoPAL proteins after storage at 4 °C for 30 days were between 75 and 83%. In addition, the tolerance against denaturants of the immobilized BoPAL proteins were significantly enhanced. As a result, the dextran polyaldehyde natural cross-linking agent can effectively replace traditional chemical cross-linking agents for the immobilization of the BoPAL enzymes. The PAL/nylon 6/polyvinyl alcohol (PVA)/chitosan (CS) nanofibers made are extremely stable and are practical for industrial applications in the future.

scholarly journals Enhanced Performance of Immobilized Xylanase/Filter Paper-ase on a Magnetic Chitosan Support

Catalysts ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 966
Author(s):  
Aldo Amaro-Reyes ◽  
Azariel Díaz-Hernández ◽  
Jorge Gracida ◽  
Blanca E. García-Almendárez ◽  
Monserrat Escamilla-García ◽  
...  
Keyword(s):  
Filter Paper ◽  
Catalytic Efficiency ◽  
Cost Effective ◽  
Immobilized Enzymes ◽  
Hydrolytic Activity ◽  
Industrial Applications ◽  
Biochemical Properties ◽  
Free Form ◽  
Cross Linking ◽  
Magnetic Chitosan

Enzyme immobilization on different supports has emerged as an efficient and cost-effective tool to improve their stability and reuse capacity. This work aimed to produce a stable immobilized multienzymatic system of xylanase and filter paper-ase (FPase) onto magnetic chitosan using genipin as a cross-linking agent and to evaluate its biochemical properties and reuse capacity. A mixture of chitosan magnetic nanoparticles, xylanase, and FPase was covalently bonded using genipin. Immobilization yield and efficiency were quantified. The activity of free and immobilized enzymes was quantified at different values of pH, temperature, substrate concentration (Km and Vmax), and reuse cycles. The immobilization yield, immobilization efficiency, and activity recovery were 145.3% ± 3.06%, 14.8% ± 0.81%, and 21.5% ± 0.72%, respectively, measured as the total hydrolytic activity. Immobilization confers resistance to acidic/basic conditions and thermal stability compared to the free form. Immobilization improved 3.5-fold and 78-fold the catalytic efficiency (Kcat/Km) of the xylanase and filter paper-ase activities, while immobilized xylanase and FPase could be reused for 34 min and 43 min, respectively. Cross-linking significantly improved the biochemical properties of immobilized enzymes, combined with their simplicity of reuse due to the paramagnetic property of the support. Multienzyme immobilization technology is an important issue for industrial applications.

scholarly journals Fluorescent enzyme-coupled activity assay for phenylalanine ammonia-lyases

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Mădălina E. Moisă ◽  
Diana A. Amariei ◽  
Emma Z. A. Nagy ◽  
Nóra Szarvas ◽  
Monica I. Toșa ◽  
...  
Keyword(s):  
Substrate Specificity ◽  
Directed Evolution ◽  
Cinnamic Acid ◽  
Ammonia Concentration ◽  
Industrial Applications ◽  
Acid Decarboxylase ◽  
Fluorescent Assay ◽  
General Applicability ◽  
Pal Activity ◽  
Ferulic Acid Decarboxylase

Abstract Phenylalanine ammonia-lyases (PALs) catalyse the non-oxidative deamination of l-phenylalanine to trans-cinnamic acid, while in the presence of high ammonia concentration the reverse reaction occurs. PALs have been intensively studied, however, their industrial applications for amino acids synthesis remained limited, mainly due to their decreased operational stability or limited substrate specificity. The application of extensive directed evolution procedures to improve their stability, activity or selectivity, is hindered by the lack of reliable activity assays allowing facile screening of PAL-activity within large-sized mutant libraries. Herein, we describe the development of an enzyme-coupled fluorescent assay applicable for PAL-activity screens at whole cell level, involving decarboxylation of trans-cinnamic acid (the product of the PAL reaction) by ferulic acid decarboxylase (FDC1) and a photochemical reaction of the produced styrene with a diaryltetrazole, that generates a detectable, fluorescent pyrazoline product. The general applicability of the fluorescent assay for PALs of different origin, as well as its versatility for the detection of tyrosine ammonia-lyase (TAL) activity have been also demonstrated. Accordingly, the developed procedure provides a facile tool for the efficient activity screens of large mutant libraries of PALs in presence of non-natural substrates of interest, being essential for the substrate-specificity modifications/tailoring of PALs through directed evolution-based protein engineering.

Elemental chlorine-free bleaching of North American hardwood kraft pulps: Evaluation of oxidant-reinforced extraction variables on overall bleaching optimization

TAPPI Journal ◽  
2013 ◽  
Vol 12 (10) ◽  
pp. 33-41 ◽  
Author(s):  
BRIAN N. BROGDON
Keyword(s):  
Response Surface ◽  
Chlorine Dioxide ◽  
North American ◽  
Yield Loss ◽  
Alkaline Extraction ◽  
Kraft Pulps ◽  
Pulp Bleaching ◽  
Response Surface Models ◽  
Elemental Chlorine ◽  
Surface Models

This investigation evaluates how higher reaction temperatures or oxidant reinforcement of caustic extraction affects chlorine dioxide consumption during elemental chlorine-free bleaching of North American hardwood pulps. Bleaching data from the published literature were used to develop statistical response surface models for chlorine dioxide delignification and brightening sequences for a variety of hardwood pulps. The effects of higher (EO) temperature and of peroxide reinforcement were estimated from observations reported in the literature. The addition of peroxide to an (EO) stage roughly displaces 0.6 to 1.2 kg chlorine dioxide per kilogram peroxide used in elemental chlorine-free (ECF) bleach sequences. Increasing the (EO) temperature by Δ20°C (e.g., 70°C to 90°C) lowers the overall chlorine dioxide demand by 0.4 to 1.5 kg. Unlike what is observed for ECF softwood bleaching, the presented findings suggest that hot oxidant-reinforced extraction stages result in somewhat higher bleaching costs when compared to milder alkaline extraction stages for hardwoods. The substitution of an (EOP) in place of (EO) resulted in small changes to the overall bleaching cost. The models employed in this study did not take into account pulp bleaching shrinkage (yield loss), to simplify the calculations.

scholarly journals Design and Optimization of a Centrifugal Pump for Slurry Transport Using the Response Surface Method

Machines ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 60
Author(s):  
Khaled Alawadhi ◽  
Bashar Alzuwayer ◽  
Tareq Ali Mohammad ◽  
Mohammad H. Buhemdi
Keyword(s):  
Response Surface ◽  
Centrifugal Pump ◽  
Industrial Applications ◽  
Pump Efficiency ◽  
Optimized Design ◽  
Centrifugal Pumps ◽  
Local Pressure ◽  
Design And Optimization ◽  
Geometry Characteristic ◽  
Line Design

Since centrifugal pumps consume a mammoth amount of energy in various industrial applications, their design and optimization are highly relevant to saving maximum energy and increasing the system’s efficiency. In the current investigation, a centrifugal pump has been designed and optimized. The study has been carried out for the specific application of transportation of slurry at a flow rate of 120 m3/hr to a head of 20 m. For the optimization process, a multi-objective genetic algorithm (MOGA) and response surface methodology (RSM) have been employed. The process is based on the mean line design of the pump. It utilizes six geometric parameters as design variables, i.e., number of vanes, inlet beta shroud, exit beta shroud, hub inlet blade draft, Rake angle, and the impeller’s rotational speed. The objective functions employed are pump power, hydraulic efficiency, volumetric efficiency, and pump efficiency. In this reference, five different software packages, i.e., ANSYS Vista, ANSYS DesignModeler, response surface optimization software, and ANSYS CFX, were coupled to achieve the optimized design of the pump geometry. Characteristic maps were generated using simulations conducted for 45 points. Additionally, erosion rate was predicted using 3-D numerical simulations under various conditions. Finally, the transient behavior of the pump, being the highlight of the study, was evaluated. Results suggest that the maximum fluctuation in the local pressure and stresses on the cases correspond to a phase angle of 0°–30° of the casing that in turn corresponds to the maximum erosion rates in the region.

A fast and accurate solution to optimal design of eddy-current PMCs with standard disc type

2021 ◽  
pp. 1-19
Author(s):  
Zheng rong Xia ◽  
Yong chen Pei ◽  
Dong xu Wang ◽  
Shun Wang
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Optimal Solution ◽  
Industrial Applications ◽  
Accurate Solution ◽  
Parameter Determination ◽  
Experimental Investigations ◽  
Fe Model ◽  
Contribution Rate ◽  
Standard Disc

Although permanent magnet couplings (PMCs) have been under research for many years and have found successful industrial applications, this is still a technology under development. Accurate parameter determination is of significance for performance analysis and critical decisions on PMC design. However, the determination can often lead to an unacceptable increase in computation, especially when finite elements (FE) are used. The study aims to develop an FE model that is used for the structural design of a standard-disc type PMC for optimal torque. For the quick and accurate design, an integration optimal solution of the response surface methodology (RSM) and the Taguchi’s method was proposed. To verify the simulation, a series of experimental investigations were conducted on a self-developed testing platform. Furthermore, for a minimum set of FE analyses (FEA), a quantitative indicator called contribution rate, which can reflect effect level of structure parameters on the torque, was given based on the Taguchi method. Apart from this, the orthogonal matrix was used for the reduction of the FE calculation. Based on the contribution rate, the response surface methodology was adopted for the optimal torque determination with no increase in the PM volume. According to the optimization results, a fitting formula, which considers the contribution rates of the optimization variables, was presented. The results suggest that the FE simulations agree very well with the experiments, and the fitting formula can be used in the PMC design.

Modeling and optimization of ultrasound‐assisted cinnamon extraction process using fuzzy and response surface models

2018 ◽  
Vol 42 (2) ◽  
pp. e12978
Author(s):  
Nur Cebi ◽  
Osman Sagdic ◽  
Abdulrahman Mohammed Basahel ◽  
Mohammed Abdullah Balubaid ◽  
Osman Taylan ◽  
...  
Keyword(s):  
Response Surface ◽  
Extraction Process ◽  
Modeling And Optimization ◽  
Response Surface Models ◽  
Surface Models ◽  
Ultrasound Assisted

Optimization of the Global Static and Dynamic Performance of a Vehicle Body by Means of Response Surface Models

2012 ◽  
Author(s):  
Pavlina Mihaylova ◽  
Alessandro Pratellesi ◽  
Niccolò Baldanzini ◽  
Marco Pierini
Keyword(s):  
Response Surface ◽  
Dynamic Performance ◽  
The Body ◽  
Vehicle Body ◽  
Fe Model ◽  
Structural Modifications ◽  
Response Surface Models ◽  
First Choice ◽  
Surface Models ◽  
Body In White

Concept FE models of the vehicle structure are often used to optimize it in terms of static and dynamic stiffness, as they are parametric and computationally inexpensive. On the other hand they introduce modeling errors with respect to their detailed FE equivalents due to the simplifications made. Even worse, the link between the concept and the detailed FE model can be sometimes lost after optimization. The aim of this paper is to present and validate an alternative optimization approach that uses the detailed FE model of the vehicle body-in-white instead of its concept representation. Structural modifications of this model were applied in two different ways — by local joint modifications and by using mesh morphing techniques. The first choice was motivated by the strong influence of the structural joints on the global vehicle performance. For this type of modification the plate thicknesses of the most influent car body joints were changed. In the second case the overall car dimensions were modified. The drawback of using detailed FE models of the vehicle body is that they can be times bigger than their concept counterparts and can thus require considerably more time for structural analysis. To make the approach proposed in this work a feasible alternative for optimization in the concept phase response surface models were introduced. With them the global static and dynamic performance of the body-in-white was represented by means of approximating polynomials. Optimization on such mathematical models is fast, so the choice of the optimization algorithm is not limited only among local-search strategies. In the current study Genetic Algorithm was used to increase the chances for finding better design alternatives. Two different optimization problems were defined and solved. Their final solutions were presented and compared in terms of structural modifications and resulting responses. The approach in this paper can be successfully used in the concept phase as it is fast and reliable and at the same time it avoids the problems typical for concept models.

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