Improving the stability of uricase from Aspergillus flavus by osmolytes: Use of response surface methodology for optimization of the enzyme stability

AbstractThe effect of various process parameters on the stability of TiO2 nanofluid, which can mostly be defined as zeta potential and particle size, was studied using response surface methodology (RSM) by the design of experiments and was predicted through a trained artificial neural network (ANN). The process parameters studied were weight percentage of surfactant (sodium lauryl sulfate) (0.01–0.2 wt%) and the value of pH (10–12). Central composite design and the RSM were employed to develop a mathematical model as well as to define the optimum condition. A three-layered feed-forward ANN model was designed and used for the prediction of the stability parameters. From the analysis of variance, the significant factors that affected the experimental design responses were also identified. The predicted stability parameters using the RSM and ANNs were compared using figures and tables. It is shown that the trained ANN outperformed the RSM in terms of accuracy and prediction of obtained results.

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Optimization of Aflatoxin Production of Aspergillus flavus on Peanuts

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.887-888.605 ◽

2014 ◽

Vol 887-888 ◽

pp. 605-609

Author(s):

Chu Shu Zhang ◽

Jie Sun ◽

Li Na Yu ◽

Jie Bi ◽

Jian Xiong Feng ◽

...

Keyword(s):

Response Surface Methodology ◽

Relative Humidity ◽

Linear Relationship ◽

Water Content ◽

Response Surface ◽

Aspergillus Flavus ◽

Previous Experiment ◽

Aflatoxin Production ◽

Influence Of Water ◽

Production Conditions

To optimize aflatoxin production of Aspergillus flavus on peanut, the response surface methodology were applied based on previous experiment. The results showed that the influence of water content of peanuts,time and relative humidity were obvious and were not linear relationship. The optimal aflatoxin production conditions were that water content of peanuts was12%, the time was 7 days, relative humidity was 80%.

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Reduction of Aflatoxin –B1 in Cocoa Beans Contaminated with Aspergillus Flavus by the Essential Oil of Aframomum Danielli Using Response Surface Methodology

Sharing Knowledge Making a Difference: The Role of International Scientific Cooperation. - World Sustainable Development Outlook ◽

10.47556/b.outlook2011.9.23 ◽

2011 ◽

pp. 401-417

Author(s):

Aroyeun Shamsideen Olusegun ◽

◽

Adegoke Gabriel Olanrewaju ◽

Varga Janos ◽

◽

...

Keyword(s):

Response Surface Methodology ◽

Essential Oil ◽

Response Surface ◽

Aspergillus Flavus ◽

Aflatoxin B1 ◽

Cocoa Beans

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The Influence of Pluronic F-127 Modification on Nano Zero-Valent Iron (NZVI): Sedimentation and Reactivity with 2,4-Dichlorophenol in Water Using Response Surface Methodology

Catalysts ◽

10.3390/catal10040412 ◽

2020 ◽

Vol 10 (4) ◽

pp. 412 ◽

Cited By ~ 1

Author(s):

Yajun Li ◽

Yongxiang Zhang ◽

Qi Jing ◽

Yuhui Lin

Keyword(s):

Response Surface Methodology ◽

Response Surface ◽

Colloidal Stability ◽

Removal Rate ◽

Zero Valent Iron ◽

Quadratic Model ◽

Biphasic Model ◽

Sedimentation Behavior ◽

Nano Zero Valent Iron ◽

The Stability

Nano zero-valent iron (NZVI) is widely used for reducing chlorinated organic pollutants in water. However, the stability of the particles will affect the removal rate of the contaminant. In order to enhance the stability of nano zero-valent iron (NZVI), the particles were modified with F-127 as an environmentally friendly organic stabilizer. The study investigated the effect of the F-127 mass ratio on the colloidal stability of NZVI. Results show that the sedimentation behavior of F-NZVI varied at different mass ratios. A biphasic model was used to describe the two time-dependent settling processes (rapid sedimentation followed by slower settling), and the settling rates were calculated. The surface morphology of the synthesized F-NZVI was observed with a scanning electron microscope (SEM), and the functional groups of the samples were analyzed with Fourier Transform Infrared Spectroscopy (FTIR). Results show that the F-127 was successfully coated on the surface of the NZVI, and that significantly improved the stability of NZVI. Finally, in order to optimize the removal rate of 2,4-dichlorophenol (2,4-DCP) by F-NZVI, three variables were tested: the initial concentration 2,4-DCP, the pH, and the F-NZVI dosage. These were evaluated with a Box-Behnken Design (BBD) of response surface methodology (RSM). The experiments were designed by Design Expert software, and the regression model of fitting quadratic model was established. The following optimum removal conditions were determined: pH = 5, 3.5 g·L−1 F-NZVI for 22.5 mg·L−1 of 2,4-DCP.

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Use of response surface methodology to study the effect of media composition on aflatoxin production by Aspergillus flavus

Mycotoxin Research ◽

10.1007/s12550-012-0151-x ◽

2012 ◽

Vol 29 (1) ◽

pp. 39-45 ◽

Cited By ~ 9

Author(s):

Mahboob Ahmad ◽

Malik M. Ahmad ◽

Rifat Hamid ◽

M. Z. Abdin ◽

Saleem Javed

Keyword(s):

Response Surface Methodology ◽

Response Surface ◽

Aspergillus Flavus ◽

Aflatoxin Production ◽

Media Composition

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Investigation of combined effects of wax, calcites and clay on emulsion stability using response surface methodology

World Journal of Engineering ◽

10.1108/wje-03-2018-0086 ◽

2019 ◽

Vol 16 (6) ◽

pp. 751-767

Author(s):

Abubakar Abubakar Umar ◽

Ismail Mohd Saaid ◽

Rashidah Mohd Pilus ◽

Aliyu Adebayor Sulaimon ◽

Berihun Mamo Negash ◽

...

Keyword(s):

Response Surface Methodology ◽

Response Surface ◽

Emulsion Stability ◽

Continuous Phase ◽

Visual Observation ◽

Combined Effects ◽

Stable Emulsion ◽

Content Type ◽

Proxy Model ◽

The Stability

Purpose This paper aims to examine the effect of wax, calcites and clay on the stability of petroleum emulsions. It proposes a proxy model that takes into cognizance the presence of solids other than asphaltene and resin. This study aims to investigate the combined effects of these solids on the stability of emulsions and show their relevance or otherwise in the creation of petroleum emulsions. Design/methodology/approach This paper used synthetic emulsions based on a response surface methodology using different weight concentrations of wax, calcites and clay. A Box–Behnken design model was adopted and the effects of the different variables on emulsion stability were analyzed. The conventional visual observation (batch testing) was augmented with a more robust technique of studying emulsion stability (Turbiscan) based on light backscattering or transmission. Analysis of variance and other statistics were used to analyze the results. Findings The paper makes an available proxy model that can predict the stability of petroleum emulsions in the presence of wax, calcites and clays. The findings suggest that in the presence of significant amount of wax (0.3 Wt.%), the presence of relatively lower concentration of clay (0.1 Wt.%) produces very stable petroleum emulsions. The results show that the most stable emulsion is obtained when significant amount of wax exists in the continuous phase and that a concentration of calcites more than wax (in a ratio of at least 2:1) produces an emulsion that separates very fast, indicating low stability. Research limitations/implications Due to the variations in the amount of asphaltene and resins in crude oils, the proxy model cannot generally predict the stability of every emulsion that forms in the presence of these solids. To have a more general model, it should include asphaltene/resin. This can be tested further. Practical implications This paper provides useful information to the oil industry, especially where formation of severely stable emulsion is a problem. It also establishes the relationship that exists between solids in emulsion stabilization. Originality/value This paper satisfies a demand on the effects of other surface-active materials in addition to asphaltene/resin in stabilizing petroleum emulsions.

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Response surface methodology for optimal immobilization of Aspergillus niger ATCC 1015 lipase by adsorption method

International Journal of Biological Research ◽

10.14419/ijbr.v4i1.6008 ◽

2016 ◽

Vol 4 (1) ◽

pp. 56 ◽

Cited By ~ 1

Author(s):

Michael Osho ◽

Tope Popoola ◽

Tolulope Adeleye ◽

Christianah Adetunji

Keyword(s):

Response Surface Methodology ◽

Aspergillus Niger ◽

Response Surface ◽

Enzyme Stability ◽

Immobilized Lipase ◽

Crosslinking Agent ◽

Lipase Production ◽

Full Potential ◽

Enzyme Loading ◽

Adsorption Method

Optimization of Vegetable Sponge (Luffa aegyptiaca) (VS) - immobilization conditions of Aspergillus niger ATCC 1015 lipase on Solid State Fermentation (SSF) was carried out using Response Surface Methodology (RSM). Four independent variables (temperature, pH, enzyme loading and enzyme stability) were optimized using Central Composite Design of RSM for lipase production in a solid rice bran-physic nut cake medium. The optimal immobilization conditions obtained were 45 °C, pH 7.0, 2.5% (w/v) enzyme loading and 32.5% (v/v) enzyme stability (using glutaraldehyde as crosslinking agent) resulted into lipase activity of 98.6 Ug-1. The result demonstrates the potential application of vegetable sponge under SSF system in immobilizing lipase, thus contributed to efficiency of the use of this biomatrix as an immobilizing agent. The statistical tools employed predicted the optimal conditions for the production of the immobilized lipase thus revealing the full potential of the support.

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Extraction Optimization of Astragaloside IV by Response Surface Methodology and Evaluation of Its Stability during Sterilization and Storage

Molecules ◽

10.3390/molecules26082400 ◽

2021 ◽

Vol 26 (8) ◽

pp. 2400

Author(s):

Lin Xu ◽

Kongjiong Wei ◽

Jiaolong Jiang ◽

Lianfu Zhang

Keyword(s):

Response Surface Methodology ◽

Response Surface ◽

Alkaline Solution ◽

Retention Rate ◽

Traditional Approach ◽

Radix Astragali ◽

Astragaloside Iv ◽

Practical Applications ◽

Significant Difference ◽

The Stability

Radix Astragali is referred to as a variety of food-medicine herb, and it is commonly applied as Traditional Chinese Medicine (TCM). However, it is extremely difficult to extract its bio-active compounds (astragaloside IV) and apply it in food processing efficiently, which restricts its practical applications. In this study, the conditions required for the extraction of astragaloside IV were optimized by following the response surface methodology. More specifically, ammonia with a concentration of 24% was used as an extracting solvent, the solid–liquid ratio was 1:10 (w:v); the Radix Astragali was soaked at 25 °C for 120 min in advance and then stirred at 25 °C for 52 min (150 rpm) to extract astragaloside IV. This method promoted the transformation of other astragalosides into astragaloside IV and replaced the traditional approach for extraction, the solvent reflux extraction method. The yield of astragaloside IV reached the range of 2.621 ± 0.019 mg/g. In addition, the stability of astragaloside IV was evaluated by detecting its retention rate during sterilization and 60-day storage. As suggested by the results, the astragaloside IV in acidic, low-acidic, and neutral solutions was maintained above 90% after sterilization (95 °C and 60 min) but below 60% in an alkaline solution. High temperature and short-term sterilization approach is more appropriate for astragaloside IV in an alkaline solution. It was also found out that the astragaloside IV obtained using our method was maintained over 90% when stored at room temperature (25 °C), and there was no significant difference observed to low temperature (4 °C) in solutions regardless of acidity.

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Optimization of Mangifera indica L. Kernel Extract-Loaded Nanoemulsions via Response Surface Methodology, Characterization, Stability, and Skin Permeation for Anti-Acne Cosmeceutical Application

Pharmaceutics ◽

10.3390/pharmaceutics12050454 ◽

2020 ◽

Vol 12 (5) ◽

pp. 454 ◽

Cited By ~ 1

Author(s):

Worrapan Poomanee ◽

Watcharee Khunkitti ◽

Wantida Chaiyana ◽

Pimporn Leelapornpisid

Keyword(s):

Response Surface Methodology ◽

Response Surface ◽

Ex Vivo ◽

Mangifera Indica ◽

Skin Permeation ◽

Skin Barrier ◽

The Stability ◽

Spherical Droplets ◽

Central Composite ◽

Excellent Stability

This study aimed to optimize nanoemulsions loading with Mangifera indica L. kernel extract using response surface methodology for enhancing the stability and skin permeation of the extract. Central composite design was employed for optimization and evaluation of three influencing factors including hydrophile-lipophile balance (HLB), % co-surfactant (PEG-7 glyceryl cocoate), and surfactant-to-oil ratio (SOR) on physical properties of the nanoemulsions. The desired nanoemulsions were then incorporated with the extract and characterized. Physicochemical properties of the extract-loaded nanoemulsions and their antibacterial effects against Propionibacterium acnes were also evaluated after storage at various conditions and compared to those of the initial. Ex vivo skin permeation was also investigated. The factors significantly (p < 0.05) influenced on droplet size, polydispersity index (PDI), and zeta potential, especially HLB of the surfactant and its combined effects with co-surfactant and SOR. The extract-loaded nanoemulsions revealed a very small spherical droplets (size of 26.14 ± 0.22 nm) with narrow size distribution (PDI of 0.16 ± 0.02). The formulation also presented an excellent stability profile and successfully enhanced antibacterial stability of the extract comparing with the extract solution. Ex vivo skin permeation study illustrated that the extract in nanoemulsions could be delivered through a primary skin barrier to reach viable epidermis dermis layers. In conclusion, the affinity of surfactant and hydrophilicity of the system play a crucial role in nanoemulsions’ characteristics. Such results might provide promising anti-acne nanoemulsions with the notable capacities of extract stabilization and permeation enhancing which will be further clinically evaluated.

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