Full Factorial Central Composite Design Research Articles

Optimization of Medium Composition for the Production of Neomycin by Streptomyces fradiae NCIM 2418 in Solid State Fermentation.

Neomycin production of Streptomyces fradiae NCIM 2418 was optimized by using response surface methodology (RSM), which is powerful mathematical approach comprehensively applied in the optimization of solid state fermentation processes. In the first step of optimization, with Placket-Burman design, ammonium chloride, sodium nitrate, L-histidine, and ammonium nitrate were established to be the crucial nutritional factors affecting neomycin production significantly. In the second step, a 24 full factorial central composite design and RSM were applied to determine the optimal concentration of significant variable. A second-order polynomial was determined by the multiple regression analysis of the experimental data. The optimum values for the important nutrients for the maximum were obtained as follows: ammonium chloride 2.00%, sodium nitrate 1.50%, L-histidine 0.250%, and ammonium nitrate 0.250% with a predicted value of maximum neomycin production of 20,000 g kg−1 dry coconut oil cake. Under the optimal condition, the practical neomycin production was 19,642 g kg−1 dry coconut oil cake. The determination coefficient (R 2) was 0.9232, which ensures an acceptable admissibility of the model.

Adsorption of Malachite Green from Aqueous Solution using Activated Ntezi Clay: Optimization, Isotherm and Kinetic Studies

The adsorption of malachite green from aqueous solution using a local low cost adsorbent, acid activated Ntezi clay, was investigated. The low cost adsorbent was activated with different concentrations of sulphuric acid and the physicochemical properties of the adsorbent were determined and the structural properties were analyzed using XRF and XRD. The adsorption process was studied as a function of different process parameters such as temperature, adsorbent dosage, contact time, particle size and stirring speed. These process parameters were optimized using response surface methodology (RSM). The significance of the different process parameters and their combined effect on the adsorption efficiency has been established through a full factorial central composite design. The equilibrium modeling was analyzed using Langmuir, Freundlich, Dubini-Radushkevich and Temkin isotherm equation and the results of the experimental data follows the Langmuir adsorption isotherm. Adsorption kinetics follows the pseudo-second order with intra-particle diffusion as the rate-determining step. This investigation has shown that local clay mineral can be modified and used as a good adsorbent in the removal of impurities from contaminated water.

A statistical approach for the enhanced production of thermostable alkaline protease showing detergent compatibility activity from Bacillus circulans

Response surface methodology (RSM) was employed to enhance the production of a thermostable alkaline protease from Bacillus circulans. Significant influences of peptone, yeast extract, and glucose on protease production were noted with a one-variable-at-a-time optimization strategy. Then, a full factorial central composite design (CCD) was applied to study the effects of glucose, peptone, and yeast extract to determine the optimal concentrations of these compounds for protease production by B. circulans under shake flask fermentation conditions. The statistical reliability and significance of the model was validated by an F-test for analysis of variance (ANOVA); enzyme production was improved significantly under optimized conditions. The enzyme was purified by ammonium sulphate fractionation, and gel filtration chromatography. Maximum enzyme activity was observed at 60°C temperature, and at pH 10. Alkaline protease from B. circulans showed excellent compatibility and stability in the presence of commercial detergents like Ariel, Surf Excel, Tide, Rin, Nirma, Wheel, and Doctor and showed excellent blood destaining effectiveness with commercial detergents.

Uranium adsorption studies on hydrothermal carbon produced by chitosan using statistical design method

A new hydrothermal cross-linking chitosan (HCC) was prepared by hydrothermal reaction at a mild temperature (180 °C) to diminish the solubility in acid solution, and the amine groups were almost retained during the hydrothermal reaction characterized by FT-IR and the dissolution rate in pH 3 solution decreased from 89.6 to 12.6 %. The effects of initial pH, contact time, initial concentration and temperature on the sorption capacity are discussed using 24 full-factorial central composite design using response-surface methodology. The HCC showed the highest uranium sorption capacity at initial pH of 7.92 and contact time of 273.6 min with 24 full-factorial central composite design and the maximum adsorption capacity was 273 mg/g. The adsorption process could be well defined by the Langmuir isotherm and the thermodynamic parameters, ∆G°(298 K), ∆H° and ∆S°, demonstrated shown that the sorption process of U(VI) onto HCC was feasible, spontaneous and endothermic in nature.

Modeling of biosorption of Cu(II) by alkali-modified spent tea leaves using response surface methodology (RSM) and artificial neural network (ANN)

In the present work, spent tea leaves were modified with Ca(OH)2 and used as a new, non-conventional and low-cost biosorbent for the removal of Cu(II) from aqueous solution. Response surface methodology (RSM) and artificial neural network (ANN) were used to develop predictive models for simulation and optimization of the biosorption process. The influence of process parameters (pH, biosorbent dose and reaction time) on the biosorption efficiency was investigated through a two-level three-factor (23) full factorial central composite design with the help of Design Expert. The same design was also used to obtain a training set for ANN. Finally, both modeling methodologies were statistically compared by the root mean square error and absolute average deviation based on the validation data set. Results suggest that RSM has better prediction performance as compared to ANN. The biosorption followed Langmuir adsorption isotherm and it followed pseudo-second-order kinetic. The optimum removal efficiency of the adsorbent was found as 96.12 %.

Removal of reactive blue 19 from aqueous solution by pomegranate residual-based activated carbon: optimization by response surface methodology

BackgroundIn this research, response surface methodology (RSM) was applied to optimize Reactive Blue 19 removal by activated carbon from pomegranate residual. A 24 full factorial central composite design (CCD) was applied to evaluate the effects of initial pH, adsorbent dose, initial dye concentration, and contact time on the dye removal efficiency.MethodologyThe activated carbon prepared by 50 wt.% phosphoric acid activation under air condition at 500°C. The range of pH and initial dye concentration were selected in a way that considered a wide range of those variables. Furthermore, the range of contact time and adsorbent dose were determined based on initial tests. Levels of selected variables and 31 experiments were determined. MiniTab (version 16.1) was used for the regression and graphical analyses of the data obtained.ResultsIt was found that the decrease of initial dye concentration and the increase of initial pH, adsorbent dose, and contact time are beneficial for improving the dye removal efficiency. Analysis of variance (ANOVA) results presented high R2 value of 99.17% for Reactive Blue 19 dye removal, which indicates the accuracy of the polynomial model is acceptable.ConclusionsInitial pH of 11, adsorbent dose of 1.025 g/L, initial dye concentration of 100 mg/L, and contact time of 6.8 minutes found to be the optimum conditions. Dye removal efficiency of 98.7% was observed experimentally at optimum point which confirmed close to model predicted (98.1%) result.

Enzymatic production of N-acetyl-D-glucosamine by solid state fermentation of chitinase by Penicillium ochrochloron MTCC 517 using agricultural residues

The optimization studies for production of chitinase were carried out by response surface methodology (RSM) based on statistics experimental design using three substrates, which were wheat, rice and red gram bran. 24 full factorial central composite design was applied to evaluate optimal combinations of variables. These variables were chitin concentration, initial moisture content, inoculum level, and incubation time. The results of second order polynomial showed that all four variables had significant effect on chitinase production. Maximum chitinase activity was recorded for wheat bran (2443.23 U g−1) than rice (1216.65 U g−1) and red gram bran (961.32 U g−1). An overall 3-fold increase in chitinase activity was achieved using optimized strategies of RSM. Growth of the fungus on all bran particles have been visualized by scanning electron microscopy. These results indicated the potential of Penicillium ochrochloron for economical production of chitinase using agricultural residues. TLC and HPLC analysis of colloidal chitin hydrolysate with partially purified chitinases revealed that the major reaction product was monomeric GlcNAc indicating the potential of these enzymes for efficient production of GlcNAc.

Adsorption treatment of coal washery effluent (CWE) for the removal of suspended and dissolved particle (SDP) by chrysophylum albidium seed shell

Chrysophylum albidium seed shell was utilized as an adsorbent for suspended and dissolved particle removal from coagulated coal washery effluent. Several parameters were investigated using batch mode and 23 full factorial central composite designs (CCD) (for optimization purposes). There exist single generality in optimal values for acid treated shell (ASAA) and salt treated shell (ASAS) at pH 6.8, 30°C, 10g/L dose, 30 min equilibrium time and 1g adsorbent mass for batch mode and CCD, respectively. Equilibrium data sufficiently fit the Langmuir isotherm (R2 > 0.99 and SSE (%) ≤ 0.093). Pseudo-second order kinetics provides best correlation (R2 > 0.99 and SSE (%) < 0.1) with experimental data. Thermodynamics constants (ΔG°, ΔH° and ΔS°) were respectively evaluated as -122.190 KJ/mol, 69005.967 J/mol and 228.146 Jmol-1K-1 for ASAA and -1537.455 KJ/mol, 68008.026 J/mol and 229.523 Jmol-1K-1 for ASAS. The shell biomass promises high potential as an efficient adsorbent since the adsorption process was favorable, endothermic and spontaneous.

<b>Critical process parameters optimization for hyperthermostable β amylase production by <i>Bacillus subtilis</i> DJ5 using response surface methodology </b> - doi: 10.4025/actascibiolsci.v36i1.17427

The combined effects of significant physical and chemical factors affect hyperthermostable β amylase production under submerged fermentation by Bacillus subtilis DJ5. The above was studied using the experimental design and response surface methodology. A 23 full-factorial central composite design was chosen to analyze interactions among three factors i.e. substrate concentration, medium pH and incubation temperature. The experimental data were fitted into a polynomial model for the yield of enzyme and an optimum level was arrived at with optimized conditions. Solving the coded values using Excel equation function indicated that maximum enzyme production is possible at a substrate concentration of 7.07 mg mL-1, pH 6.622 and temperature of 35.435°C. Such prediction was validated with practical experiments in which, at the prescribed condition maximum yield of 15.62 U mg-1, nearly 1.5 fold higher than non-optimized condition was observed.

Optimization of Copper Adsorption by Soil of Polluted Wasteland using Response Surface Methodology

Copper is one of the heavy metals, which are essential but toxic at higher concentrations. High uptakes of copper may cause liver and kidney damage and even death. This study was performed to investigate copper reduction using soil as an adsorbent. A multi-step response surface methodology was applied for the maximum reduction of Cu(II) from aqueous solution to optimize the parameters that had an effect on the adsorption studies. A two-level, three-factor (23) full factorial central composite design (CCD) using Design Expert Version 7.0.0 (Stat Ease, USA) was used for the optimization of the adsorption process parameters. From the CCD design it was observed that the optimum reduction of copper was 96.22% at pH 5.50, 31.59 g l−1 of adsorbent and 90 min contact time. The deviation between the experimental and theoretical results was 0.42%.

Electrochemical Treatment of Reactive Black 5 Textile Wastewater: Optimization, Kinetics, and Disposal Study

This research reports treatment of textile wastewater containing Reactive Black 5 (RB5) and other industrial constituents which are found in textile industry effluent, by the electrochemical treatment method using aluminum electrodes. Initial pH, current density (J), and electrolysis time (t) were selected as operational variables to observe the effects on chemical oxygen demand (COD) removal efficiency (Y1), dye removal efficiency (Y2), and specific energy consumed (Y3) (kWh/kg of COD removed). A response surface methodology (RSM) with full factorial central composite design (CCD) was used for designing and optimizing responses. To optimize the multiple responses, multi-response optimization with a desirability function were utilized for maximizing Y1 and Y2, and simultaneously minimizing Y3. To address issues of treated wastewater disposal, aluminum mass balance was performed. Electrocoagulation with subsequent adsorption, electro-floatation, and electro-oxidation were found to be the mechanism for removal of the pollutants.

Contribution of hot spring bacterial consortium in cadmium and lead bioremediation through quadratic programming model

In the present investigation, a number of experiments have been conducted to isolate microbial strains from Taptapani Hot Spring Odisha, India for bioremediation of cadmium and lead. The strains Stenotrophomonas maltophilia (SS1), Aeromonas veronii (SS2) and Bacillus barbaricus (SS3) have shown better adaptation to metal tolerance test, with different concentrations of cadmium and lead and hence have been selected for further studies of metal microbial interaction and optimization. The results of bioremediation process indicate that consortium of thermophilic isolates adsorbed heavy metals more effectively than the individually treated isolates. Therefore, A 24 full factorial central composite design has been employed to analyze the effect of metal ion concentration, microbial concentration and time on removal of heavy metals with consortium. Analysis of variance (ANOVA) shows a high coefficient of determination value. The kinetic data have been fitted to pseudo-first order and second-order models. The isotherm equilibrium data have been well fitted by the Langmuir and Freundlich models. The optimum removal conditions determined for initial ion concentration was 0.3g/l; contact time 72h; microbial concentration, 3ml/l; and pH 7. At optimum adsorption conditions, the adsorption of cadmium and lead are found to be 92% and 93%, respectively, and presence of metals was confirmed through EDS analysis.

STATISTICAL OPTIMIZATION OF PIGMENT PRODUCTION BY Monascus sanguineus UNDER STRESS CONDITION

Natural pigments are produced by the Monascus sp., which are used for coloring food substances. The intent of this study was to optimize the pigment yield and biomass produced from the unexplored Monascus sanguineus in submerged culture under stress conditions. For inducing thermal stress, the spores were incubated at various temperatures at higher ranges. For inducing osmotic stress, varied concentrations of NaCl, glycerol, and peptone were used. The medium components were optimized by response surface methodology (RSM). The combined effects of the four medium constituents mentioned were studied using a 24 full factorial central composite design (CCD). The relationships between the predicted values and actual values, independent variable, and the response were calculated according to a second-order quadratic model. It was deduced that the variable with the leading effect was the linear effect of glycerol concentration. Furthermore, the quadratic effects of peptone and the interactive effects of temperature and glycerol were more noteworthy than other factors. The optimum values for the test variables in coded factors were found to be spores treated with 70°C for temperature, 0.25 M for glycerol, 0.51% (w/v) for peptone, and 1.25% (w/v) for NaCl, corresponding to a maximum red pigment yield of 55.67 color value units (CVU)/mL. With optimized conditions, the pigment yield was almost three times the yield observed with the control.

The impact of manufacturing variables on in vitro release of clobetasol 17-propionate from pilot scale cream formulations

Objectives: The purpose of the study was to evaluate the effect of different homogenization speeds and times, anchor speeds and cooling times on the viscosity and cumulative % clobetasol 17-propionate released per unit area at 72 h from pilot scale cream formulations. A 24 full factorial central composite design for four independent variables were investigated.Materials and methods: Thirty pilot scale batches of cream formulations were manufactured using a Wintech® cream/ointment plant. The viscosity and in vitro release of CP were monitored and compared to an innovator product that is commercially available on the South African market, namely, Dermovate® cream.Results and discussion: Contour and three-dimensional response surface plots were produced and the viscosity and cumulative % CP released per unit area at 72 h were found to be primarily dependent on the homogenization and anchor speeds. An increase in the homogenization and anchor speeds appeared to exhibit a synergistic effect on the resultant viscosity of the cream whereas an antagonistic effect was observed for the in vitro release of CP from the experimental cream formulations. The in vitro release profiles were best fitted to a Higuchi model and diffusion proved to be the dominant mechanism of drug release that was confirmed by use of the Korsmeyer–Peppas model.Conclusion: The research was further validated and confirmed by the high prognostic ability of response surface methodology (RSM) with a resultant mean percentage error of (±SD) 0.17 ± 0.093 suggesting that RSM may be an efficient tool for the development and optimization of topical formulations.

Multi-Response Optimization of Epoxidation Process Parameters of Rapeseed Oil Using Response Surface Methodology (RSM)-Based Desirability Analysis

The primary efforts of this investigation stand focused on formulating a biodegradable lubricant with good thermo-oxidative stability and low pour point. Rapeseed oil was chosen to this end and was chemically modified via epoxidation, hydroxylation and transesterification processes. This study focuses on multi-response optimization of epoxidation of rapeseed oil with performic acid as oxygen carrier generated in situ. Experiments were conducted using full factorial central composite design. Response Surface methodology-based desirability analysis was employed for the optimization of process parameters namely reaction time and temperature based on the multiple performance characteristics including oxirane content and % conversion. The mathematical models were developed and tested for adequacy using analysis of variance, and other adequacy measures using the developed models. The main and interaction effects of the input variables on the predicted responses were also investigated. The optimization results showed that the reaction time of 3.23 h and the temperature of 70.74 °C were necessary to maximize oxirane content and % conversion in the epoxidation process.

Adsorption studies of As(III) from wastewater with a novel adsorbent in a three-phase fluidized bed by using response surface method

Existing overviews of arsenic removal include technologies that have traditionally been used (oxidation, precipitation/coagulation/membrane separation/adsorption) in static bed, with far less attention paid to fluidized bed. The objective of this study is to investigate the possibility of using cashew nut shale waste as an alternative adsorbent for the removal of arsenic (III) ions from aqueous solutions by using gas–liquid–solid fluidized bed. The effect of gas velocity, liquid velocity, initial static bed height and average particle size on the adsorption of arsenic (III) by cashew nut shale waste is investigated using batch methods. The single and combined effects of operating parameters such as gas velocity, liquid velocity, initial static bed height and average particle size on the adsorption of arsenic (III) from wastewater are analyzed using response surface methodology (RSM). A 24 full factorial central composite experimental design was employed. Analysis of variance (ANOVA) showed a high coefficient of determination value (R2=0.9611) and satisfactory prediction second-order regression model was derived. The optimum operating conditions were determined as gas velocity, 12.5m/s; liquid velocity, 0.04m/s; initial static bed height, 0.1m and average particle size of 1.27mm. At optimum adsorption conditions, the adsorption of arsenic (III) from wastewater in a three phase fluidized bed is found to be 92.5464%.

Bioconversion to chitosan: A two stage process employing chitin deacetylase from Penicillium oxalicum SAEM-51

Chitin deacetylase from Penicillium oxalicum SAEM-51 was evaluated for bioconversion of chitin to chitosan in a two stage chemical and enzymatic process. Variations in morphology, crystallinity and thermal properties following chemical treatment were evaluated by scanning electron microscopy, X-ray diffraction, differential scanning calorimetry and thermogravimetric analysis. Degree of deacetylation of the substrates was determined using FT-IR and elemental analysis. The pretreatment of substrate led to the decrease in crystallinity and formation of amorphous chitinous substrates to facilitate enzyme reaction. The treated chitin was further subjected to enzymatic deacetylation employing chitin deacetylase from P. oxalicum SAEM-51 to produce chitosan with considerably higher degree of deacetylation. Maximum deacetylation (79.52%) was achieved using superfine chitin, owing to its porous structure and low crystallinity. Further, derivation of reaction variables, i.e. substrate amount and enzyme dose through full-factorial central composite design led to enhanced degree of deacetylation with formation of 90% deacetylated chitosan.

Optimization of biodiesel production from castor oil using factorial design

In this study, optimization of biodiesel production from castor oil using full factorial design was investigated. The biodiesel production was carried out in a batch laboratory scale reactor by alkaline-catalyzed transesterification process. Experimental design was used in the evaluation of process variables. Effects of temperature, methanol/oil molar ratio and catalyst concentration were optimized according to the 23 full factorial central composite design (CCD). For determining the influence of purification methods on biodiesel yield, different purification methods were applied to the product after transesterification reaction. Second-order model was obtained to predict biodiesel yield as a function of these variables. According to the experimental results this process gave an average yield of biodiesel more than 90%.

Parametric and multiple response optimization for the electrochemical treatment of textile printing dye-bath effluent

In this study, treatment of textile printing dye-bath effluent (DBE) has been performed by electro-coagulation (EC) method using aluminum (Al) electrode in a batch mode. Various operating parameters such as initial pH (pHo), current density (J), electrolysis time (t) and inter electrode distance (d) were varied so as to see their effect on multiple responses namely chemical oxygen demand (COD) removal (Y1), color removal (Y2) and specific energy consumed (kWh/kg of COD removed; Y3). Full factorial central composite design (CCD) has been used for carrying out experiments and optimizing responses Y1, Y2 and Y3. Multi-response optimization with desirability function approach has been used to simultaneously maximize Y1 and Y2, and minimize Y3. Optimized values of various responses were: Y1=94%, Y2=99.7% and Y3=0.011kWh/kg of COD removed. Scum and sludge generated during EC of DBE have also been analyzed for the possibility of their disposal.

Grafted Carrageenan Gel Disks and Beads with Polyethylenimine and Glutaraldehyde for Covalent Immobilization of Penicillin G Acylase

The precursor for production of 65% worldwide antibiotics, 6-aminopenicillanic acid, has been produced using covalently immobilized penicillin G acylase (PGA) onto modified grafted carrageenan gels. Two shapes of gel were prepared, gel disks and gel beads by using the parallel plates and Encapsulator devises, respectively. Different sizes of gel disks and beads were tested to choose the best sizes for both gel types. 2 2 Full-factorial central composite design (CCD) was applied for optimisation of enzyme loading process. The results revealed that maximal enzyme loading of 11.07 and 14.30 U/g of gel disks and beads respectively could be achieved after soaking the gels in an enzyme loading solution of 20 U of PGA for 16 h for both gel types. The generated model was found to be very adequate for PGA immobilization process 91% accuracy was attained for gel disks as the experimental value was 11.07 U/g disk compared to 10.1 U/g disk for the predicted value while 95% accuracy was attained using gel beads as the experimental value was 14.30 U/g beads compared to 14.07 U/g beads for the predicted value. This result is 40% higher than that obtained in our previous work using gel disks. The immobilization of PGA onto gel beads increased the optimum pH from 6 to 6.5–7 while the reaction temperature increased dramatically from 45 � Ct o 75 � C compared to the free enzyme, respectively. Thus, the modified carrageenan-polyethylenimine-glutaraldehyde gel beads could be a good and promising candidate for the industrial use.