Full Factorial Central Composite Design Research Articles

Experimental design methodology for optimising catalytic performance of Ni/Ce/<I>α</I>-Al<SUB>2</SUB>O<SUB>3</SUB> catalyst for methane steam reforming

AbstractThe performance of a Ni/Ce/α-Al2O3 catalyst was optimised using a central composite design methodology to enhance hydrogen production and methane conversion in the catalytic steam reforming of methane. The influence of temperature, the presence of weight per cent Ni and Ce in the α-Al2O3 catalyst support and steam/methane ratio on CH4 conversion and H2 production were investigated. A 27 full factorial central composite experimental design was applied to determine the optimal levels for each of the significant variables. A second order polynomial was derived by multiple regression analysis on the experimental data. The CH4 conversion and H2 production increased significantly when the temperature was raised for the catalyst with a 10 wt-% content of Ni. Steam addition improved the CH4 conversion and H2 production; however, this required a higher operating temperature. Using this methodology, the optimum experimental values of 93·1%CH4 conversion and 73·5 vol.-%H2 were obtained using a catalyst with ...

Enzyme pretreatment and negative pressure cavitation extraction of genistein and apigenin from the roots of pigeon pea [Cajanus cajan (L.) Millsp.] and the evaluation of antioxidant activity

An enzyme pretreatment and negative-pressure cavitation extraction (E-NPCE) method was investigated for extraction genistein and apigenin from pigeon pea roots. The important parameters involved in E-NPCE process were optimized by single-factor experiments and then critical parameters were investigated by a 23 full factorial central composite design (CCD) to optimize extract conditions. Under optimal conditions, the yields of genistein and apigenin were 0.628mg/g and 0.359mg/g, which represented an increase of 44.70% and 53.05%, respectively, compared to standard NPCE. Furthermore, from DPPH scavenging activity test the extract of E-NPCE showed better antioxidant activity than these of other methods. The results demonstrated that E-NPCE would have lower energy consumption, higher efficiency and could be an alternative method for natural compounds extraction.

Scale-up of a dye adsorption process using chemically modified rice husk: optimization using response surface methodology

Abstract This article extends our previous study on malachite green (MG) adsorption using chemically modified rice husk at shake flask level, by investigating the scale up of the dye adsorption process to a laboratory level stirred batch reactor. Response surface methodology (RSM) was employed to investigate the effect of different operating conditions on the uptake of MG. A two level three factor (23) full factorial central composite design (CCD) with the help of Design Expert Version 7.1.6 (Stat Ease, USA) was used for the optimization of the adsorption process and to evaluate the effects and interactions of process variables: initial solution pH (4.0–10.0), initial dye concentration (100–500 mg/l), and adsorbent dose (10–50 g/l). Multiple response optimization was applied to the experimental data to discover the optimal conditions for a set of response, simultaneously, by using a desirability function. The optimum conditions for MG adsorption were found to be 8.30, 500 mg/l and 29.31 g/l respectively, ...

Scale-up of a dye adsorption process using chemically modified rice husk: optimization using response surface methodology

Abstract This article extends our previous study on malachite green (MG) adsorption using chemically modified rice husk at shake flask level, by investigating the scale up of the dye adsorption process to a laboratory level stirred batch reactor. Response surface methodology (RSM) was employed to investigate the effect of different operating conditions on the uptake of MG. A two level three factor (23) full factorial central composite design (CCD) with the help of Design Expert Version 7.1.6 (Stat Ease, USA) was used for the optimization of the adsorption process and to evaluate the effects and interactions of process variables: initial solution pH (4.0–10.0), initial dye concentration (100–500 mg/l), and adsorbent dose (10–50 g/l). Multiple response optimization was applied to the experimental data to discover the optimal conditions for a set of response, simultaneously, by using a desirability function. The optimum conditions for MG adsorption were found to be 8.30, 500 mg/l and 29.31 g/l respectively, for initial solution pH, initial dye concentration and adsorbent dose. Under these conditions, the removal efficiency was found to be 90.83%.

Determination and Optimization of Flavonoid and Extract Yield from Brown Mango using Response Surface Methodology

The optimum extraction conditions to obtain the highest flavonoid content and extract yield from Mangifera pajang pericarp (MPP) were analyzed using response surface methodology (RSM). A full factorial central composite design was used to investigate the effects of ethanol concentration (20–80%), temperature (30–65°C) and liquid to solid ratio (20–50 mL/g) on the recovery of extract yield and flavonoids. A second order polynomial model produced a satisfactory fitting of the experimental data with regard to extract yield (R 2 = 0.9890, p < 0.0001) and flavonoids (R 2 = 0.9652, p < 0.0001). The optimum conditions to obtain higher extract yield, were 54%, 50°C, and 42.4 mL/g, while for flavonoids were 68%, 57°C, and 20.2 mL/g, respectively. The experimental values agreed with those predicted with 99% and 96% confidence interval for extract yield and flavonoids respectively. This indicates the suitability of RSM in optimizing the extraction of flavonoids and extract yield from MPP.

Scale up of dextran production from a mutant of Pediococcus pentosaceus (SPAm) using optimized medium in a bioreactor

The mutant of Pediococcus pentosaceus (SPAm) produced earlier by UV-mutagenesis exhibiting higher dextransucrase activity as compared to wild-type was used. The generated mutant SPAm gave 12.2 mg/ml, a 20% higher dextran than wild-type. Response surface methodology was carried out for further enhancement of dextran production. To enhance dextran production by the mutant SPAm, Plackett-Burman Design and a 2² full factorial Central Composite Design was employed. After response optimization, the optimum concentration of sucrose and yeast extract was 5.115% (w/v) and 0.635% (w/v), respectively. The experimental values of dextran 36.0 mg/ml at flask level and 35.0 mg/ml at bioreactor level were in good agreement with the predicted value of 40.8 mg/ml. The increase in dextran production by the mutant SPAm using the optimized medium was 3 fold higher as compared to unoptimized medium.

Optimal hydrolysis of mustard oil to erucic acid: A biocatalytic approach

In this study, response surface methodology was applied to maximize production of erucic acid from lipase catalyzed mustard oil hydrolysis. Regioselective porcine pancreas lipase was used as catalyst. A quadratic model was developed by applying 24 full factorial central composite design. The optimal conditions obtained on numerical optimization of this model were; temperature 24.2°C, pH 8.70, enzyme concentration 2.71mg/g oil and buffer concentration 1.25g/g oil. Maximum response, i.e., ‘percentage of total erucic acid formed’ was 95.5% in 6h, much better than the conversion obtained by earlier single variable optimization method. The two most significant variables were pH and buffer concentration. Interaction between temperature and buffer concentration also had significant effect.

Optimization of carbamazepine removal in O 3/UV/H 2O 2 system using a response surface methodology with central composite design

This study used an ozone/ultraviolet/hydrogen peroxide (O 3/UV/H 2O 2) system to remove carbamazepine (CBZ) from water using a second-order response surface methodology (RSM) experiment with a five-level full-factorial central composite design (CCD) for optimization. The effects of both the primary and secondary interactions of the photocatalytic reaction variables, including O 3 concentration ( X 1 ), H 2O 2 concentration ( X 2 ), and UV intensity ( X 3 ), were examined. The O 3 concentration significantly influenced CBZ and total organic carbon (TOC) removal as well as total inorganic nitrogen ion production (T-N) ( p < 0.001). However, CBZ, TOC removal, and T-N production were enhanced with increasing O 3 and H 2O 2 concentrations up to certain levels, and further increases in O 3 and H 2O 2 resulted in adverse effects due to hydroxyl radical scavenging by higher oxidant and catalyst concentrations. UV intensity had the most significant effect on T-N production ( p < 0.001). Complete removal of CBZ was achieved after 5 min. However, only 34.04% of the TOC and 36.99% of T-N were removed under optimal concentrations, indicating formation of intermediate products during CBZ degradation. The optimal ratio of O 3 (mg L − 1 ): H 2O 2 (mg L − 1 ): UV (mW cm − 2 ) were 0.91:5.52:2.98 for CBZ removal, 0.7:18.93:12.67 for TOC removal, and 0.94: 4.85:9.03 for T-N production, respectively.

Response Surface Optimization for Removal of Cadmium from Aqueous Solution by Waste Agricultural Biosorbent Psidium guvajava L. Leaf Powder

AbstractResponse surface methodology (RSM) was applied to study the combined effects of the various parameters namely, pH, biosorbent dosage, cadmium concentration and temperature, and to optimize the process conditions for the maximum removal of cadmium using Psidium guvajava L. leaf powder. In order to obtain the mutual interactions between the variables and to optimize these variables, a 24 full factorial central composite design using RSM was employed. The analysis of variance (ANOVA) of the quadratic model demonstrates that the model was highly significant. The model was statistically tested and verified by experimentation. A maximum cadmium removal of 93.2% was obtained under the following optimum conditions: aqueous cadmium concentration 40.15 mg/L, adsorbent dosage 0.5 g/50 mL solution, pH 5.0, and temperature (35°C). The value of desirability factor obtained was 1.

Response surface methodology for optimizing process parameters for the mass production of Beauveria bassiana conidiospores

Beauveria bassiana is an insect pathogenic fungus and is currently being exploited as an effective commercial mycoinsecticide. Solid state fermentation is the most efficient way to mass produce B. bassiana conidiospores on solid substrates. Statistical optimization strategy was adopted to maximize the conidia production through solid state fermentation. Four substrates viz., rice (polished), crushed sorghum, wheat bran and rice bran at variable moisture content and yeast extract concentration were used. A full factorial central composite design was used to design the experiment and response surface method was used to study the optimal parameters required for large scale production. Optimization of the two most important factors like moisture content and yeast extract concentration at varied levels conferred best conidial yield of 28.8 × 109 /gm for the mixed substrate rice + wheat bran at 35% moisture content and 1.5% yeast extract concentration. Key words: Beauveria bassiana, central composite design, conidiospores, response surface methodology, solid state fermentation.

Optimization process parameters for in-situ synthesis of ammonia by catalytic hydrolysis of urea with fly ash in a batch reactor for safe feedstock in power plants

In this study, catalytic urea hydrolysis for production of ammonia in presence of fly ash, at optimum condition, was investigated in a batch reactor. The single and combined effects of operating parameters such as initial feed concentrations, temperature, fly ash doses, times and stirring speed on the production of ammonia from urea were analyzed using response surface methodology. A 25 full factorial central composite experimental design was employed. Analysis of variance (ANOVA) showed a high coefficient of determination value (R2= 0.963) and satisfactory prediction second order regression model was derived. The optimum production conditions were determined as initial feed concentration 19.9 wt. % of urea, temperature 175°C, fly ash dose 7.5g/L, reaction time 25 min and stirring speed 769 rpm. At optimum conversion conditions, the conversion of urea for production of ammonia was found to be 99.8 %.

Spirulina enhances the viability of Lactobacillus rhamnosus E/N after freeze-drying in a protective medium of sucrose and lactulose

Response surface methodology (RSM) was used to optimize a protective medium for enhancing the viability of Lactobacillus rhamnosus E/N cells during lyophilization. Spirulina, sucrose and lactulose were selected, on the basis of a Plackett-Burman factorial design, as important protectants having the following protective effects on cell viability: 102.025, 36.885 and -34.42, respectively. A full-factorial central composite design was applied to determine optimal levels of three used agents. The optimal protective medium composition was determined to be: Spirulina 1.304% (w/v), lactulose 5.48% (w/v), and sucrose 13.04% (w/v) (Polish Patent P-393189). The predictive value of cell viability in this medium was 89.619%, and experimental viability obtained during freeze-drying was 87.5%. In this study, Spirulina was used for the first time as the protective agent in freeze-drying medium, significantly increasing lactobacilli viability and giving synbiotic character of the final product.

Enhanced Production of Iranian Kefir Grain Biomass by Optimization and Empirical Modeling of Fermentation Conditions Using Response Surface Methodology

This study focused on the optimization of key process parameters for maximizing kefir grain biomass yield using statistical methodology. A response surface methodology (RSM) was developed to describe the effects of whey lactose and yeast concentrations, temperature and pH on increases in kefir grain biomass using cheese whey as a fermentation medium. Initially, one factor at a time was applied to evaluate the effect of different nitrogen sources. The results showed that the concentration of yeast extract significantly influenced the biomass increase. Then, a 24 full-factorial central composite design was used to optimize the process conditions. By using multiple regression analysis, the experimental data were fitted to a second-order polynomial model. RSM analysis indicated good correlation between experimental and predicted values. The most suitable combination of variables for higher biomass increase (76.13%) was 88.4 and 21.3 g/l, 5.2, and 20 °C for concentration of whey lactose, concentration of yeast extract, pH, and temperature, respectively. At these optimal conditions, biomass increased by 81.34%, which was close to the amount predicted by the model.

Optimization of chromium(VI) sorption potential using developed activated carbon from sugarcane bagasse with chemical activation by zinc chloride

An adsorbent prepared from sugarcane bagasse with chemical activation by zinc chloride was used to study its sorption potential on removing chromium(VI). In this work the application of response surface methodology (RSM) is presented for optimization of removal of Cr(VI) ions from aqua solutions using activated carbon as adsorbent. While the goal of adsorption of chromium optimization was to improve adsorption conditions in batch process, i.e., to minimize the adsorbent dose and to increase the initial concentration of Cr(VI). A 24 full factorial central composite design experimental design was employed. Analysis of variance (ANOVA) showed a high coefficient of determination value (R2=0.99) and satisfactory prediction second-order regression model was derived. Maximum chromium removal efficiency was predicted and experimentally validated. The optimum adsorbent dose, temperature, initial concentration of Cr(VI) and initial pH of the Cr(VI) solution were found to be 6.85g/L, 40°C, 77.5mg/l, and 8.58 respectively. Under optimal value of process parameters, high removal (>87%) was obtained for Cr(VI).

Purification and medium optimization of α-amylase from Bacillus subtilis 168

α-Amylase was first time isolated and purified from Bacillus subtilis 168 (1A1). Purified α-amylase fraction showed a single protein band with a molecular weight of 55 kD. Chemical characterization of the purified α-amylase revealed optimum amylolytic activity at 37°C and pH 7.0 using starch as substrate. It was stable at pH 5.0 to 9.0 and at temperatures 25–70°C. Culture conditions were optimized by using statistics-based experimental designs to enhanced α-amylase (EC.3.2.1.1) production. A two level fractional factorial Plackett-Burman design was used for the preliminary screening significant media components and conditions. Response surface methodology (RSM) involving a 2 4 full-factorial central composite design (CCD) and a second-order polynomial equation was then employed to identify the relationship between the α-amylase yield and the four significant variables. Optimal levels of the significant variables for the maximum α-amylase yield were starch 2.55 g/l, yeast extract 8.4 g/l, sodium chloride 8.1% and 48 h of incubation. Mean value of α-amylase yield was 639.7 IU/ml, which was in excellent agreement with the predicted value (633.5 IU/ml). Key wor ds: Bacillus, α-amylase, optimization, Plackett-Burman design, response surface methodology.

Optimization of lipase production by Staphylococcus warneri EX17 using the polydimethylsiloxanes artificial oxygen carriers

In this research, the combined effects of polydimethylsiloxane (PDMS) and different conditions of oxygen volumetric mass transfer coefficient (k(L)a) on lipase production by Staphylococcus warneri EX17 were studied and optimized in bioreactor cultures. Raw glycerol from biodiesel synthesis was used as the sole carbon source. Full-factorial central composite design and the response surface methodology were employed for the experimental design and analysis of the results. The optimal polydimethylsiloxane concentration and mass coefficient transfer (k(L)a) were found to be 13.5% (v/v) and 181 h(-1), respectively. Under these conditions, the maximal cell production obtained was 10.0 g/l, and the volumetric lipase activities of approximately 490 U/l, after 6 h of cultivation. These results are in close agreement with the model predictions. Results obtained in this work reveal the positive effects of PDMS on oxygen volumetric mass transfer coefficient (k(L)a) in the Staphylococcus warneri EX17 cultivation and lipase production.

Optimal fermentation conditions for maximizing the ethanol production by Kluyveromyces fragilis from cheese whey powder

Cheese whey powder (CWP) is an attractive raw material for ethanol production since it is a dried and concentrated form of CW and contains lactose in addition to nitrogen, phosphate and other essential nutrients. In the present work, deproteinized CWP was utilized as fermentation medium for ethanol production by Kluyveromyces fragilis. The individual and combined effects of initial lactose concentration (50–150 kg m−3), temperature (25–35 °C) and inoculum concentration (1–3 kg m−3) were investigated through a 23 full-factorial central composite design, and the optimal conditions for maximizing the ethanol production were determined. According to the statistical analysis, in the studied range of values, only the initial lactose concentration had a significant effect on ethanol production, resulting in higher product formation as the initial substrate concentration was increased. Assays with initial lactose concentration varying from 150 to 250 kg m−3 were thus performed and revealed that the use of 200 kg m−3 initial lactose concentration, inoculum concentration of 1 kg m−3 and temperature of 35 °C were the best conditions for maximizing the ethanol production from CWP solution. Under these conditions, 80.95 kg m−3 of ethanol was obtained after 44 h of fermentation.

Optimization of amylase production from Bacillus sp. using statistics&lt;br&gt;based experimental design

Production of amylase under submerged fermentation Bacillus sp. was investigated using wheat bran, soybean meal and CaCO 3 (WSC) medium. Response surface methodology (RSM) was used to evaluate the effect of the main variables, i.e., pH (11.35), temperature (35.16°C) and inoculum size (2.95%) on amylase production by applying a full factorial central composite design (CCD). The mutual interaction between these variables resulted into 4.64 fold increase in amylase activity as compared to the non-optimized environmental factors in the basal medium.

Factorial Optimization and Kinetics of Coal Washery Effluent Coag-Flocculation By &amp;lt;i&amp;gt;Moringa Oleifera&amp;lt;/i&amp;gt; Seed Biomass

Factorial optimization and kinetics of coal washery effluent (CWE) coag-flocculation by Moringa oleifera seed has been investigated at room temperature based on standard method of bench scale jar test. Moringa oleifera coag-flocculant (MOC) was produced according to work reported by Ghebremichael. A 23 full factorial central composite design was employed for the experimental design and analysis of results with respect to optimization. The combined effects of pH, dosage and settling time on the particle (turbidity) removal was studied using response surface methodology. Kinetic data generated were confronted with specified kinetic models for the evaluation of functional kinetics parameters. The optimal values of pH, dosage and settling time were recorded at 8,400mg/l and 25 min, respectively. The results of the major kinetic parameters recorded are 2,0.002l/mg.min, and 0.79 min for order of reaction, coag-flocculation reaction rate constant and coagulation period, respectively. The minimum removal efficiency recorded was 95% at 3mins of coag-flocculation. The results, while re affirming MOC as efficient coag-flocculant, confirmed that theory of perikinetics holds for the studied system at the conditions of the experiment.

Statistical optimization of process variables by response surface methodology to enhance phenol degradation by Pseudomonas putida (NCIM 2102)

Removal efficiency of phenol from aqueous solutions was determined using Pseudomonas putida (NCIM 2102). Experiments were made as a function of pH (4 - 9), temperature (28 - 36oC), and agitation speed (100 - 200 rpm). Optimization of these three process parameters for phenol degradation was studied. Statistically designed experiments using response surface methodology was used to get more information about the significant effects and the interactions between these three parameters. A 23 full-factorial central composite design was employed for experimental design and for analysis of the results. A second order polynomial regression model, has been developed using the experimental data. It was found that the degrading potential of P.putida (NCIM 2102) was strongly affected by the variations in pH, temperature and agitation speed. The experimental values were in good agreement with the predicted values and the correlation coefficient was found to be 0.9871. The optimum process conditions for maximizing phenol degradation were recognized as follows: pH (7.49), temperature (29.99oC), and agitation speed (138.89) rpm.