Box-Behnken Response Surface Methodology Research Articles

Enhancement of Exochitinase Production by Bacillus licheniformis AT6 Strain and Improvement of N-Acetylglucosamine Production.

A strain producing chitinase, isolated from potato stem tissue, was identified as Bacillus licheniformis by biochemical properties and 16S RNA sequence analysis. Statistical experimental designs were used to optimize nine independent variables for chitinase production by B. licheniformis AT6 strain in submerged fermentation. Using Plackett-Burman design, (NH4)2SO4, MgSO4.7H2O, colloidal chitin, MnCl2 2H2O, and temperature were found to influence chitinase production significantly. According to Box-Behnken response surface methodology, the optimal fermentation conditions allowing maximum chitinase production were (in gram per liter): (NH4)2SO4, 7; K2HPO4, 1; NaCl, 1; MgSO4.7H2O, 0.1; yeast extract, 0.5; colloidal chitin, 7.5; MnCl2.2H2O, 0.2; temperature 35°C; pH medium 7. The optimization strategy led to a 10-fold increase in chitinase activity (505.26±22.223mU/mL versus 50.35±19.62mU/mL for control basal medium). A major protein band with a molecular weight of 61.9kDa corresponding to chitinase activity was clearly detected under optimized conditions. Chitinase activity produced in optimized medium mainly releases N-acetyl glucosamine (GlcNAc) monomer from colloidal chitin. This enzyme also acts as an exochitinase with β-N-acetylglucosaminidase. These results suggest that B. licheniformis AT6 secreting exochitinase is highly efficient in GlcNAc production which could in turn be envisaged as a therapeutic agent or as a conservator against the alteration of several ailments.

Novel approach for preparation of poly (ionic liquid) catalyst with macroporous structure for biodiesel production

An efficient poly (ionic liquid) catalyst for biodiesel production was synthesized from Brønsted acidic ionic liquid 1-vinyl-3-(3-sulfopropyl) imidazolium hydrogen sulfate [VSIM][HSO4] through free radical polymerization from a novel approach, where Fe3O4 particles acted as hard template. The template could be easily removed in short time and macrospores formed after the removal of Fe3O4. The structure of the polymer was characterized by different techniques and the results demonstrated that the macroporous polymeric network was multi-layered and exhibited repeating units of SO3H and HSO4 with fine separation efficiency, as a novel heterogeneous acidic catalyst. The catalytic performance of the macroporous polymer was assessed in the esterification reaction of oleic acid for biodiesel production and the Box-Behnken response surface methodology (RSM) was applied for maximizing the biodiesel yield by optimizing process variables at 80°C. Under the optimum conditions (reaction time was 4.5h, catalyst amount was 8.5wt%, and alcohol/acid molar ratio was 12:1), a high biodiesel yield of 92.6% was obtained. The polymeric catalyst also showed favorable reusability after six runs. The combination of macrospores with poly (ionic liquid) would significantly reduce the limitation of mass transfer in biodiesel production compared with other porous solid acidic catalysts.

An integrated, quality by design (QbD) approach for design, development and optimization of orally disintegrating tablet formulation of carbamazepine

The objective of the present study was to design and develop a formulation for orally disintegrating tablets (ODTs) of carbamazepine using quality by design principles. The target product profile (TPP) and quality target product profile (QTPP) of ODTs were identified. Risk assessment was carried out by leveraging prior knowledge and experience to define the criticality of factors based on their impact by Ishikawa fishbone diagram and preliminary hazard analysis tool. Box–Behnken response surface methodology was used to study the effect of critical factors on various attributes of ODTs. The independent factors selected were compression pressure (X1), concentration of sublimating agent (volatile material) (X2), disintegrant concentration (X3) and the responses were tablet crushing strength, tablet porosity, disintegration time, water absorption time, tablet friability and drug dissolution. ANOVA and lack of fit test illustrated that selected independent variables had significant effect on the response variables, and excellent correlation was observed between actual and predicted values. Optimization by desirability function indicated that compression pressure, X1 (1534 lbs), ammonium bicarbonate concentration, X2 (7.68%) and Kollidon® CL-SF concentration, X3 (6%) were optimum to prepare ODT formulation of carbamazepine of desired attributes complying with QTPP. Thus, in the present study, a high level of assurance was established for ODT product quality and performance.

Application of Box-Behnken design and response surface methodology for multi-optimization of laser cutting of AA5052/ZrO2 metal−matrix composites

A laser source is most popular in industrial world for its high cutting efficiency and productivity. In the present research work, laser cutting of aluminium metal−matrix composite has been studied. The investigations have been done to analyse the influence of various parameters on surface and quality characteristics of aluminium alloy 5052 reinforced with ZrO2 particles. The effect of laser parameters was analysed on striation angle, heat affected zone and kerf deviation. Response surface methodology has been applied using Box-Behnken design for the statistics analysis. Heat affected zone and striation formation of laser cut surface were examined using scanning electron microscope and optical microscope. The effect of arc radius, cutting speed and percentage of reinforced particles was found to be significant on all output characteristics. The predicted response surface methodology (RSM) model was validated with experimental data for determination of accuracy level.

Enhanced phenylpyruvic acid production with Proteus vulgaris by optimizing of the fermentation medium

Alpha keto acids are important food additives, which commonly produced by microbial deamination of amino acids. In this study, production of phenylpyruvic acid (PPA), which is the alpha keto acid of phenylalanine was enhanced in 2-l bench scale bioreactors by optimizing of fermentation medium composition using the Box-Behnken Response Surface Methodology (RSM). Optimum glucose, yeast extract, and phenylalanine concentrations were determined to be 119.4 g 1−1, 3.7 g 1−1, and 14.8 g 1−1, respectively, for PPA production, and 163.8 g 1−1, 10.8 g 1−1, and 9.8 g 1−1, respectively, for biomass production. Under these optimum conditions, PPA concentration was enhanced to 1349 mg 1−1, which was 28% and 276% higher than the unoptimized bioreactor and shake-flask fermentations, respectively. Moreover, P. vulgaris biomass concentration was optimized at 4.36 g 1−1, which was 34% higher than under the unoptimized bioreactor condition. Overall, this study demonstrated that optimization of the fermentation media improved PPA concentration and biomass production in bench scale bioreactors compared to previous studies in the literature and sets the stage for scale up to industrial production.

Magnetic Material Grafted Poly(phosphotungstate-based acidic ionic liquid) As Efficient and Recyclable Catalyst for Esterification of Oleic Acid

A magnetically recyclable catalyst was prepared by embedding magnetic nanoparticle in poly(phosphotungstate-based ionic liquid) matrix. The obtained hybrid material was characterized by XRD, FT-IR, SEM, TEM, TGA, and VSM. The results indicated that Fe3O4 was successfully implanted in multilayer poly(ionic liquid), and the catalyst possessed open active sites (see SEM) to reactants and a high magnetization value. The combination of poly(ionic liquid) matrix with magnetic nanoparticle enhanced the structure stability and favored the separation performance. Esterification of oleic acid with ethanol was conducted in the presence of prepared catalyst, and the Box–Behnken response surface methodology was applied for maximizing the oleic acid conversion by optimizing process variables at 90 °C. Under the optimum conditions (reaction time, 5 h; catalyst amount, 13 wt %; alcohol/acid molar ratio, 12:1), the conversion of oleic acid reached 93.4%. Besides, the catalyst presented fine reusability after six runs and ...

Development and Statistical Optimization of Sustained Release Gastro Retentive Floating Tablets of Cephalexin

The aim of present study was to formulate the sustained release floating tablets of Cephalexin (CPL) by direct compression method and optimized by Box-behnken Response Surface Methodology (RSM). A computer aided optimization technique was employed to investigate the formulation design by Box-behnken RSM (Design Expert Software version 8.0.7.1) to study the effect of the concentration of various polymer blends on the property of CPL gastroretentive floating tablets like floating lag time (FLT), cumulative percent drug release (%CDR). The independent variables investigated were polymeric concentrations (X1) and dependent variables were FLT (Y1), %CDR (Y2) in 0.1N HCl buffer at the end of 8 h. Results from precompression evaluation indicated that all the 17 and optimized formulation F18 were complied with the pharmacopoeial limits. The predicted value for FLT and %CDR obtained from software was compared with the experimental value of FLT and %CDR of optimized formulation F-18 and it was observed that the obtained experimental value was in very close agreement with the predicted value. The optimized formulation (F-18) gave good FLT and %CDR when compared to the 17 formulations. Key words: Cephalexin: Design Expert Software; Floating tablets; Optimization; Response Surface Methodology.

Density-based separation performance of a secondary air-distribution fluidized bed separator (SADFBS) for producing ultra-low-ash clean coal

Stable fluidization with consistent flow and a reasonable separating density are keys to the highly efficient separation in a secondary air-distribution fluidized bed separator (SADFBS). In this study, a binary dense medium was formed by mixing fine coal with magnetite powders. The optimum secondary air-distribution layer (SAL) height of 13mm was obtained by verifying the density uniformity of the bed. The suitable static bed height of 60–100mm was determined by comparing the fluctuation of bed pressure drops. In addition, the distribution characteristics of the fine coal particles in various bed layers indicated that the feeding fine coal content should be not more than 10%, which was verified by the bubbling performance in the bed. Box–Behnken Response Surface Methodology (BB-RSM) was employed to evaluate the effects of static bed height (Hs), fluidization number (N), and feeding fine coal content (P) on the combustible material recovery θ of feed coal. Based on the experimental data, a mathematical model was established to describe the relationship between combustible material recovery and the operational factors. The influential degree of various factors on θ was N>Hs>P. The separation results of SADFBS suggested that θ value was maximized when Hs=100mm, N=1.45, and P=4%, which showed a good separation performance. The ash content of clean coal reached the lowest value of 2.65% when Hs=80mm, N=1.70 and P=7%, with a yield of 64.89% and a combustible material recovery of 74.86%. The product is generally considered to be ultra-low-ash clean coal which is the raw materials for activated carbon production.

Effects of electrodeposition synthesis parameters on the photoactivity of nanostructured tungsten trioxide thin films: Optimisation study using response surface methodology

The main aim of this study was to synthesize and characterise nanostructured tungsten trioxide (WO3) thin films via electrodeposition and subsequently, optimise the electrodeposition synthesis parameters using response surface methodology (RSM). Statistical Box–Behnken RSM design was used to investigate and optimise the effects of four independent electrodeposition synthesis parameters, namely: deposition time, precursor tungsten (W) concentration, annealing temperature and pH. In addition, the synergistic interaction between different electrodeposition synthesis parameters was identified and quantified in enabling a higher photoactivity achievable by nanostructured WO3 thin films. Resultant nanostructured WO3 thin films were characterised using field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and photocurrent density measurements under one-Sun irradiation. From the electrodeposition synthesis process, it was found that there was a gradual increase in the nanocrystallites WO3 size from 30 nm to 70 nm when the annealing temperature was varied between 400 °C and 600 °C. XRD results verified the existence of the same photoactive phase of monoclinic WO3 with increasing annealing temperature with the preferred growth orientation along the {002} planar. Whilst from the Box–Behnken RSM design, it was found that the optimum deposition time, precursor W concentration, annealing temperature and pH were: 60 min, 0.15 mol/L, 600 ℃, and pH 1.0, respectively. The highest photocurrent density of 120 µA/cm2 was measured at 1 V (versus Ag/AgCl) for nanostructured WO3 thin film synthesized at the optimum conditions as informed by the Box–Behnken RSM. Further analysis and validation of the Box–Behnken RSM model using analysis of variance (ANOVA) revealed that the RSM-derived statistical predictive model was robust, adequate and representative to correlate the various electrodeposition synthesis parameters to photocurrent density. This study highlights the importance to systematically optimise the electrodeposition synthesis parameters in order to achieve a higher photocurrent density on nanostructured WO3 thin film for sustainable hydrogen production from photoelectrochemical water splitting reaction.

Box–Behnken response surface methodology for optimization of operational parameters of compression ignition engine fuelled with a blend of diesel, biodiesel and diethyl ether

The response surface method is adopted to express the output parameter (brake thermal efficiency) as a function of engine parameters including compression ratio (CR), injection pressure (IP) and injection timing (IT). The range of engine parameters selected is: 16 ≤ CR ≤ 18; 180 ≤ IP ≤ 220 bar; 15° ≤ IT ≤ 250 BTDC. It is shown that the proposed Box–Behnken design required only 15 runs of experiments for the response surface between output parameters and engine parameters. Using ‘Design Expert’ software, 2D and 3D plots are generated. Such plots give an idea of domination of process variables and exhibit the trend of interaction between the variables. Moreover, a statistical significant test (ANOVA) is carried out to develop a ‘Regression Model’. The results of ANOVA suggested that the proposed ‘Regression Model’ is best fit with Standard Deviation of 0.093, Adjusted R2 of 0.9619 and Adequate Precision of 19.686. Further the validation of ‘Regression Model’ is carried out by comparing the predicated values of thermal efficiency with that of experimental observations. The comparison suggested that the model is robust enough to predict thermal efficiency of the CI engine over a wide range of operating conditions with error less than 1%. Finally an optimum combination of engine parameters i.e. CR = 18, IP = 220 bar and IT = 200 before top dead centre is proposed.

An investigation on the Young’s modulus and impact strength of nanocomposites based on polypropylene/linear low-density polyethylene/titan dioxide (PP/LLDPE/TiO2) using response surface methodology

In this study, an attempt was made to optimize Young’s modulus and impact strength of nanocomposites based on polypropylene/linear low-density polyethylene/nanotitanium dioxide (PP/LLDPE/TiO2) using the experimental design. Experiments were designed according to Box–Behnken response surface methodology to screen out significant factors from linear low-density polyethylene (LLDPE), styrene–ethylene–butylene–styrene (SEBS as a compatibilizer), and titanium dioxide (TiO2) nanoparticles. The thermal behavior of the nanocomposites was also studied by means of differential scanning calorimetry (DSC). From the statistical analysis, the most important parameter affecting Young’s modulus and impact strength was obtained as LLDPE of PP/LLDPE/TiO2 nanocomposites, which was followed by TiO2 and SEBS. Finally, based on the desirability function, the optimized factors for maximum Young’s modulus and impact properties were found as LLDPE, 60 wt%; TiO2, 2.6 wt%; and SEBS, 2.3 wt%.

A Bacillus coagulans and its application in pine pollen fermentation

In the study, a potential L-lactic acid-producing bacillus-strain LT1 was isolated. It was identified as Bacillus coagulans based on its morphological, physiological, biochemical properties, and phylogenetic similarity of 16S rDNA. The fermentation conditions of pine pollen by strain LT1 were optimized using Box-Behnken design and response surface methodology. Optimum values of the tested variables for production of viable counts were an inoculum size of 9.22%, temperature=49.21°C, and an initial pH of 6.82. Under optimized conditions, the viable count was 5.49×109 CFU/mL. Finally, the single factor experiment as preliminary research for fermentation product treatment was performed.

Optimization of one-step pelletization technology of Biqiu granules by Plackett-Burman design and Box-Behnken response surface methodology

First with the qualified rate of granules as the evaluation index, significant influencing factors were firstly screened by Plackett-Burman design. Then, with the qualified rate and moisture content as the evaluation indexes, significant factors that affect one-step pelletization technology were further optimized by Box-Behnken design; experimental data were imitated by multiple regression and second-order polynomial equation; and response surface method was used for predictive analysis of optimal technology. The best conditions were as follows: inlet air temperature of 85 degrees C, sample introduction speed of 33 r x min(-1), density of concrete 1. 10. One-step pelletization technology of Biqiu granules by Plackett-Burman design and Box-Behnken response surface methodology was stable and feasible with good predictability, which provided reliable basis for the industrialized production of Biqiu granules.

Optimising clarification of carrot juice by bacterial crude pectinase

SummaryThis study was undertaken to search for potential use of crude bacterial pectinase enzyme produced from Bacillus subtilis grown on hazelnut shell hydrolysate in clarification of carrot juice and to optimize the enzyme load, pH and time using the Box–Behnken response surface methodology (RSM). The carrot juice was treated with the crude pectinase enzyme (5.60 U mL−1) at different concentrations (0.1–0.5%), pH (4–7), and time (2–6 h). The obtained enzyme was also compared with commercial fungal pectinase at identical conditions. RSM provided optimal clarification conditions of 0.5% (w/v) enzyme load, 7.0 pH, and 6 h of time estimating 100% clarity, whose experimental counterpart was 94.47 ± 0.01%. High values of coefficient of determination (R2 = 0.9631), predicted R2 (0.8989) and insignificant lack‐of‐fit (0.12) also showed that the model was successful in predicting % clarity for various combinations. This study also indicated that crude bacterial pectinase providing about 95% clarity is superior to commercial fungal pectinase, which gave 78% clarity under tested conditions, in terms of clarification ability for carrot juice.

Optimization on alcohol precipitation techniques of Liuwei Dihuang decoction by response surface methodology

The theoretical basis of the alcohol precipitation process control was provided, the alcohol precipitation was optimized and the relationship equation was got. The monod glycoside, loganin and paeoniflorin were used as the evaluation indexes to determine the impact factors of alcohol precipitation techniques of Liuwei Dihuang decoction by the Plackett-Burman experimental design and the levels of non-significant factors were identified. Then, Box-Behnken response surface methodology was used to research and discuss the critical process parameters influence the effect of alcohol precipitation and draw interaction between key process parameters and the correlation equation with index components. Through the establishment and solving the quadratic regression model of composite score, the optimum preparation conditions of alcohol precipitation techniques of liuwei were as follows: stirring speed was 580 r x min(-1), standing time was 17 hours, alcohol concentration was 34%, the density of Liuwei Dihuang decoction was 1.13. The response surface methodology for optimized alcohol precipitation techniques of Liuwei Dihuang decoction is. reasonable and feasible.

Optimization of microwave-assisted extraction of polyphenols from Quercus bark

Box–Behnken response surface methodology was used to investigate and optimize microwave assisted extraction (MAE) (treatment power and time) of antioxidant compounds, especially polyphenols, from bark extracts. Moreover, the effects of solvent composition (methanol and ethanol) particle size, and pH conditions were evaluated and optimized. In addition, the effects of MAE were compared to conventional solvent extraction at room temperature and reflux extraction (at 100°C). The results indicated that all process variables had a significant effect on polyphenol and antioxidant recovery, except for methanol (p>0.05). For instance, TPC and antioxidant activity were increased when higher power and longer treatment time were used. Optimum MAE conditions were obtained with a particle size 0.5×1×0.3 cm3, energy (power 45W and irradiation time 60min), pH 10.75, 33% of ethanol and 0.38% of methanol. Verification of predictive model showed that the model was suitable for the optimization of phenolic compounds from bark. Under optimized conditions, extraction efficiencies were increased by 3 times and 2 times respectively for total phenolic content and antioxidant recoveries, as compared to conventional methods that use the same parameters but without MAE. Moreover, the determination of phenolic profile was performed by LC–MS. The LC analysis results showed that MAE increased the content of (+)-catechin, (−)-epicatechin, (−)-epigallocatechin, syringic acid, p-coumaric acid, sinapic acid and naringenin compared to control extraction sample at the equivalent diffusion time conditions and temperature.

Optimization of solvent extraction of shea butter (Vitellaria paradoxa) using response surface methodology and its characterization

Shea butter (SB) was extracted from its kernel by using n-hexane as solvent in an optimization study. This was to determine the optima operating variables that would give optimum yield of SB and to study the effect of solvent on the physico-chemical properties and chemical composition of SB extracted using n-hexane. A Box-behnken response surface methodology (RSM) was used for the optimization study while statistical analysis using ANOVA was used to test the significance of the variables for the process. The variables considered for this study were: sample weight (g), solvent volume (ml) and extraction time (min). The physico-chemical properties of SB extracted were determined using standard methods and Fourier Transform Infrared Spectroscopy (FTIR) for the chemical composition. The results of RSM analysis showed that the three variables investigated have significant effect (p < 0.05) on the %yield of SB, with R(2) - 0.8989which showedgood fitness of a second-order model. Based on this model, optima operating variables for the extraction process were established as: sample weight of 30.04g, solvent volume of 346.04ml and extraction time of 40min, which gave 66.90% yield of SB. Furthermore, the result of the physico-chemical properties obtained for the shea butter extracted using traditional method (SBT)showed that it is a more suitable raw material for food, biodiesel production, cosmetics, medicinal and pharmaceutical purposes than shea butter extracted using solventextraction method (SBS). Fourier Transform Infrared Spectroscopy (FTIR) results obtained for the two samples were similar to what was obtainable from other vegetable oil.

Adsorption of malachite green by magnetic litchi pericarps: A response surface methodology investigation

In this work, we synthesized a novel magnetic adsorbent containing litchi pericarps, denoted as MLP, for the removal of malachite green (MG) from solution. The factors influencing MG adsorption, such as contact time, adsorbent dosage, and initial dye concentration, were optimized using the Box-Behnken response surface methodology (RSM). The adsorption isotherms as well as the kinetics and thermodynamics of the adsorption of MG onto MLP are discussed. The results showed that MLP has a maximum adsorption efficiency of 99.5% when the temperature, pH, contact time, adsorbent dosage, and initial MG concentration were optimally set as 25 °C, 6.0, 66.69 min, 5.14 g/L, and 150 mg/L, respectively. The best model to describe this process is the Langmuir isotherm, with the maximum adsorption capacity being 70.42 mg/g. In addition, the kinetics of MG adsorption onto MLP followed a pseudo-second-order model; moreover, thermodynamic analysis suggested that MG adsorption onto MLP is spontaneous and endothermic. Finally, it was found that the new magnetic adsorbent can be separated easily and rapidly from mixed solutions in the presence of an external magnetic field.

Optimization of medium components and physicochemical parameters to simultaneously enhance microbial growth and production of lypolitic enzymes by Stenotrophomonas sp.

The optimization of lipase and esterase production (LP and EP) and bacterial growth (BG) of a Stenotrophomonas sp. strain was developed. For this purpose, the effect of five different medium components and three physicochemical parameters were evaluated using a Plackett-Burman statistical design. Among eight variables, stirring speed, pH, and peptone concentration were found to be the most effective factors on the three responses under evaluation. An optimization study applying Box-Behnken response surface methodology was used to study the interactive effects of the three selected variables on LP/EP and microorganism growth. Predicted models were found to be significant with high regression coefficients (90%-99%). By using the desirability function approach, the optimum condition applying simultaneous optimization of the three responses under study resulted to be: stirring speed of 100rpm, pH of 7.5, and a peptone concentration of 10g/L, with a desirability value of 0.977. Under these optimal conditions, it is possible to achieve in the optimized medium a 15-fold increase in esterase productivity, a 117-fold increase in lipase production, and a 9-log CFU/mL increase in BG, compared with the basal medium without agitation.

Optimization of Hemicellulose Coating as Applied to Apricot Drying and Comparison with Chitosan Coating and Sulfite Treatment

AbstractDrying of hemicellulose‐coated apricots was compared to sulfuring and chitosan coating. Air velocity, temperature and hemicellulose concentration were optimized using the Box–Behnken response surface methodology against total color change (ΔE*), yellowness (Δb*) and final moisture content. Drying kinetics were evaluated by Newton, Page and Logarithmic models. Diffusion coefficient, activation energy and rehydration rate were calculated. The optimal drying conditions were found as 1 m/s of air velocity, 80C of air temperature and 3% (w/v) hemicellulose coating, which gave values of 15.2, −8.3 and 26% for ΔE*, Δb* and final moisture, respectively. The hemicellulose‐coated apricots indicated better color values than the uncoated and chitosan‐coated samples, while sulfuring still attained the best color values. Drying kinetics were best described by the Logarithmic model at 60 and 70C and Page model at 80C for 2% hemicellulose coating. Effective diffusion coefficients ranged from 2.499 to 5.742 × 10−9 and the activation energy was calculated as 33.78 kJ/mol. The hemicellulose‐coated apricots had slightly higher rehydration rate than the uncoated and sulfured samples. In conclusion, hemicellulose coating showed a promise for use in fruit drying.Practical ApplicationsTreatment of fruits with sulfur compounds (sulfur dioxide gas, sulfite solutions, etc.) prior to drying is a common practice to minimize loss in the quality of the dried fruit. In fact, use of these chemicals in foods is limited and the allowed concentration varies with countries worldwide in the range of 300–2,000 mg/kg. Because sulfur compounds can cause health problems, use of natural, renewable and abundant preservatives will be a viable alternative. In this respect, hemicellulose extracted from agricultural and food wastes can provide a low‐cost preservative and can be utilized to preserve fruits during drying. The results of this study will also provide a basis to utilize hemicellulose in various fruits other than apricots during drying and meanwhile will help reduce the concentration of sulfur compounds in foods.