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Hydrodynamic factors have been proved to effectively influence the high-performance heap leaching, hence this study evaluates them on column bioleaching of low grade uranium ore. Response surface methodology (RSM) was applied to predict the behavior of effective parameters particle size, irrigation rate, aeration rate and their interactions in the bioleaching process. Obtained results showed that the best model for the recovery of each metal was the quadratic model. The maximum values of uranium recovery at the optimum condition, (d₈₀ 5, mm particle size, 0.34, l/m²/min irrigation rate, and 210, l/m³/min aeration rate), were 63.85%. The results from the model and the experimental data show good agreement.

 

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Sclerotinia stem rot (SSR), caused by Sclerotinia sclerotiorum, is one of the most important diseases of canola (Brassica napus) in Golestan province, the leading canola producer in Iran. In order to assess the yield loss of canola caused by SSR, 80 fields were surveyed in four different regions of the province (Gorgan, Ali Abad, Kalaleh and Gonbad) during 2006-2007, and SSR intensity was recorded weekly in the fields. Study of yield loss-SSR severity relationships by linear, nonlinear and multiple regression analyses with final intensity (S_f), time to initial symptoms (t_is), Gompertz rate of disease progress (r_G), and standardized area under disease progress curve (SAUDPC) as independent variables indicate that single point and integral models were significant (P < 0.05) only in three cases. Results of multiple point models which were performed using weekly recorded SSR intensities (S₁, S₂, …), were significant in two cases and a general model for 2007 survey was developed using S₃ to S₆. Eventually, response surface models were developed for each region by integrating t_is with SSR intensity variables (S_f or SAUDPC).

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Research subject: Superabsorbents are hydrophilic hydrogels that can accommodate large amounts of water in their three-dimensional structures and have wide applications in various sciences such as pharmaceuticals, medicine, and agriculture. These materials are hydrophilic polymers that are physically or chemically cross-linked. Conversion and swelling ratio of synthesized hydrogels are two counter effects. Therefore, determining the appropriate conditions for polymerization to achieve optimal properties and swelling rate of hydrogels is a challenge for researchers.
Research approach: In this study, optimizing the synthesis conditions of semi-interpenetrating poly (acrylic acid)/xanthan hydrogels, the response surface methodology (RSM) was used by Box-Behnken design (BBD). The variables of this method were the molar ratio of the cross-linking agent (X₁), the weight percentage of xanthan gum (X₂) as the reaction medium, and the amount of initiator (X₃), each of which was considered at three levels. The evaluated responses in RSM were the rate of polymerization conversion (Y₁) and the rate of swelling (Y₂) of the hydrogels in the water.
 
Main results: Based on the 17 experiments proposed by RSM (BBD), the cross-linker, xanthan gum, and initiator were combined and radical polymerization was performed into silicone molds at 65 ° C. The results of ANOVA analysis showed that the data error of this study was small and the coefficient of determination (R2) of both proposed models for the responses Y₁ and Y₂ was higher than 0.9. The 46 experiments proposed for the optimal point by RSM (BBD) with the desirability of more than 50% indicate the synthesis of hydrogels that have both a good conversion rate and an optimal amount of swelling. For example, by 13% of cross-linking agent, 0.043 g of initiator and 1% wt. the solution of xanthan, hydrogels with a 95% conversion rate, and 102% water uptake were prepared. These hydrogels can be used in a variety of fields, including the treatment of colored wastes in factories, agriculture, pharmaceutical systems, medical attractions, and more.

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Lovastatin is a potent agent for lowering cholesterol of blood. Since one of the main reasons of mortality in developing countries is cardiovascular disease, which is caused by precipitation of fatty acid (especially cholesterol) in blood vessels; therefore diets containing lovastatin may prevent this type of disease. In this study, Lovastatin, monacolin K or competitive inhibitor of the HMG-CoA reductase (operative enzyme for cholesterol synthesis) was produced by submerged fermentation using Monascus purpureus PTCC5303. Seven chemical and nutritional parameters including maltose, peptone, MgSO4.7H2O, MnSO4.H2O, KH2PO4, thiamin and pH screened using Plackett Burman experimental design for monacolin production. Among different parameters, maltose and MgSO4.7H2O showed significant effect on biomass and monacolin production. The concentration of these agents were optimized using response surface methodology for lovastatin production in the shaker flask. The optimized medium contained 26 g/L maltose, 5 g/L peptone, 0.1 g/L MgSO4.7H2O, MnSO4.H2O 0.5 g/L, 4 g/L KH2PO4, Vitamin B1 0.1 g/L and pH 7. After 10 days of fermentation in the shaker flask with 130 rpm agitation and 30 ºC, we achieved maximum lovastatin production which was 63 mg/l.

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Research subject: Nowadays, due to the prevalence of coronavirus and the increasing use of disinfectant solutions and gels, the use of glycerin has also increased dramatically. But the suggested processes in this field need to be optimized in terms of production and energy consumption.

Research approach: In this paper, the transesterification method has studied and simulated, during which vegetable oil is converted into biofuel, and glycerin is also produced as a by-product of this process. For this purpose, process simulation of a conventional unit with 5.5 m³/min feed has been done in Hysys. Also, due to the importance of equipping the transesterification reactor, by importing the necessary process information, this equipment has been simulated in COMSOL MultiPhysics and the effective parameters have been studied in order to optimize the of product conversion. After validation of model, to better understand the factors affecting the performance of the transesterification reactor, the effect of selected parameters first examined by one-variable at the time design of experiment approach.
Main result: Finally, it has been shown that the feed temperature and the flowrate both have significance impact on quantity and quality of product and while providing a model for calculating the amount of glycerol produced per unit of energy consumed, the effective parameters are optimized by the response surface method. In optimal conditions of the ratio of product production to energy consumption, the temperature value was 470.7 K and the feed flow rate was 0.586 m³/s. According to the gained results, it can be obtained by adjusting the flow rate in the optimal amount, using a preheater in the production processes of biofuels and glycerin can have a significant effect on the amount of products produced so that the optimal temperature for the output of this preheater is at least 470.7 K should be considered. In the current research an optimization scheme has been suggested which can be used for different Biodiesel-Glycerol production units with varies range of flowrate.
 

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  In this research , the effects of three variables, soymilk concentration (0- 25%), CaCl2 (0.3-1%) and coagulation temperature (30- 40⁰C) on sensory (taste, texture) and chemical (amount of total solids, protein and fat) properties of UF Feta cheese made from cow's milk and soymilk blend were investigated. The central composite experimental design (CCD) was used and the data were analyzed using response surface methodology (RSM). Coefficients of determination, R², of fitted regression models for taste, texture, total solids, protein content and fat content were 0.965, 0.918, 0.924, 0.999 and 0.841 , respectively. The Result of analysis of variance (ANOVA) table showed that lack of fit was not significant for all response surface models at 95%. Therefore, the models for all response variables were highly adequate. The results showed that the optimum processing conditions for producing cheese with highest overall values for response variables were 15% soymilk, 0.3% CaCl2 and coagulation temperature of 38⁰C. The response values for such product are: taste 3.9, texture: 4.72, total solids:35.13%, protein:13.45 %and fat: 14.05%.  

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Endoglucanase Cel9A from Alicyclobacillus acidocaldarius (AaCel9A), a thermophile enzyme, randomly breaks β1-4 glycosidic bond between glucose units in cellulose polymer and produces oligosaccharides with reducing end. In this study, first of all, E.coli BL21 cells were transformed by pDEST17 carrying AaCel9A enzyme gene for expression of the recombinant enzyme. After expression, the recombinant enzyme was purified by Ni-NTA affinity chromatography column and the purity of the recombinant protein was analyzed by SDS-PAGE. Due to impact of the calcium, pH and temperature on AaCel9A activity, the effects of these parameters were investigated on AaCel9A activity to optimize activity condition by using Response surface methodology. The SDS-PAGE result showed that AaCel9A, with molecular weight of 59 kDa, was expressed and purified. Response surface methodology data reveal that the effect of pH on the activity of the enzyme is higher than temperature and the calcium effect is less than temperature. Results showed that the optimum condition of AaCel9A activity reaches at pH 6.35 and 64.5 ˚C as well as 4.92 mM of calcium. Finally, the high correlation between experimental and predicted date indicated that the proposed model for optimizing the enzyme activity has a high accuracy.

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Production of recombinant proteins in Escherichia coli has been very common in recent decades. Many studies and experiments have been done in order to optimize the production and expression of recombinant proteins in E.coli. One strategy is using high cell density to increase recombinant protein production such as β-NGF in the cell. Therefore, in this study for the first time bacterial cell culture in high cell density was done using glycerol and yeast extract as carbon and nitrogen sources and MgCl2 as a growth effective factor. Also the effects of overnight culture conditions on bacterial growth were evaluated. Meanwhile culture conditions were optimized using response surface methodology (RSM) and the optimum conditions were as follows: 18/23 g/lit glycerol, 14.44 g/lit yeast extract and 10mM MgCl2. Also the obtained results indicated that the 14 hours incubation at 37 °C and 180 rpm were optimum conditions for the overnight culture. Our results showed that the rate of cell growth and recombinant β-NGF production in optimized condition is significantly higher than in basic medium.

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Cellulase is one of the industrial enzymes which its production and utilization is increasingly taking into consideration due to global heed to second-generation bioethanol production. Cellulase produced by different organisms such as fungi, bacteria, insects, and plants. With increase in utilization of this enzyme and need for reduction in the enzymes price for production of second-generation bioethanol, the production of recombinant enzyme has been considered noticeably.
In this study, by investigation of corn steep liquor as nitrogen source and second carbon source after glycerol, a new medium is designed based on SYN6 salt medium then biomass and endoglucanase II production by methylotrophic yeast was optimized. Experiments designed by one-factor and response surface methodology used for optimization.
Results showed that optimum conditions for biomass and endoglucanase production are 5.5% (w/v) and 6.15% (w/v) of corn steep liquor respectively. New optimized conditions increased 41.4% and 69.7% for biomass and recombinant enzyme production respectively.

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In this research, the effects of three variables, soymilk concentration (0- 25%), CaCl2 (0.3-1%) and coagulation temperature (30- 40⁰C) on textural properties of UF Feta cheese made from cow's milk and soymilk blend were investigated. Texture profile analysis (TPA) and penetration test were used to determine textural properties of products. At TPA test, hardness, cohesiveness, springiness, gumminess, chewiness and hardness 1 work done characteristics and at penetration test, hardness adhesiveness , adhesive force and hardness 1 work done characteristics  were measured. The central composite experimental design (CCD) was used and the data were analyzed using response surface methodology (RSM). Coefficients of determination, R², of fitted regression models for all characteristics were above 0.85. The Result of analysis of variance (ANOVA) table showed that lack of fit was not significant for all response surface models at 95%. Therefore, the models for all response variables were highly adequate. Also there was extra similarity between results obtained from TPA and penetration test for same traits. Therefore, when necessary we can replace these experiments by each other.  

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Emulsion coatings were formulated and films were developed using tragacanth gum as the basic structural component. Preliminary experiments were carried out to determine the proper concentration of tragacanth gum, lipid and plasticizers in the film. The effects of different concentrations of tragacanth gum (0.65, 1, 1.5, 2, 2.35 g /g distilled water), canola oil (23, 30, 40, 50, 58 g/g tragacanth dry wt basis) and glycerol (33, 40, 50, 60, 67 g/g tragacanth dry wt basis) on water vapor permeability (WVP), mechanical properties and opacity (OP) of the films were evaluated using the response surface methodology. WVP was observed in the range of  (2.05-36) x 10^-11 and increased by tragacanth and glycerol concentration and was decreased by oil concentration. Tensile strength and elongation at break ranged between 0.67-7.15 Mpa and 1.99 – 7.8%; respectively. Increasing the amount of tragacanth gum and decreasing the glycerol and oil concentration increased tensile strength (TS) while elongation at break (EB) increased by increasing both tragacanth and glycerol concentration and decreased by increasing oil concentration. Oil was the most influential factor that affected opacity, which increased with increasing oil concentration. Models developed for WVP, EB, TS and OP had high coefficient of multiple determination (R²) values (0.983, 0.952, 0.824, 0.94) respectively.

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Protein rich legumes are suitable for the production of edible films and coatings. In this research,  pea protein isolate was obtained from defatted pea flour by alkaline extraction and acid precipitation. Then edible films were prepared from pea protein isolate. The effects of protein and glycerol concentrations on water vapor transmission rate (WVTR), mechanical properties, thickness, opacity and total color difference (ΔE) of the films were evaluated, using response surface methodology (RSM).  The results showed that WVTR, elongation, ΔE, thickness and opacity were increased, while tensile strength decreased by glycerol concentration. Increasing the concentration of protein increased tensile strength, opacity and ΔE, while decreased WVTR and elongation of the films. The model developed by RSM for the physical and mechanical properties of the films had high coefficient of multiple determination (R² >0.87) and significant F values.

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Edible films and coatings are developed to improve quality and to extend shelf-life of food products. In this study, soy protein isolate was obtained from defatted soy flour by alkaline extraction and acid precipitation. Then edible films were prepared from soy protein isolate. The effects of protein concentrations and two plasticizers of glycerol and sorbitol on some physical and mechanical properties of the films were evaluated, using response surface methodology (RSM). The results showed that  tensile strength, opacity, thickness and water vapor transmission rate (WVTR) were increased, while elongation of the films decreased by protein concentration. Increasing the concentration of glycerol and sorbitol increased WVTR, elongation, total color difference (ΔE), thickness and opacity, while declined tensile strength of the films. The model developed by RSM for the physical and mechanical properties of the films had high coefficient of multiple determination (R² >0.87) and significant F values. The models suggested that the concentration of soy protein and the type and concentrations of the plasticizers are the most influential factors with significant effects on the properties of soy protein isolate films.

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The microalgal strain Aurantiochytrium sp. shy contains considerable amounts of poly-unsaturated fatty acids (PUFAs), chiefly docosahexaenoic acid (DHA) with potential pharmaceutical and health-related attributes. Effects of various concentrations of glucose, meat extract, monosodium glutamate and sea salt on the algal biomass and DHA production have been investigated in this study. Maximum algal biomass (7.1 g/l) was obtained when the culture medium contained 60 g/l of glucose, 6 g/l of meat extract, 6 g/l monosodium glutamate and sea salt at 25ppt. Lipid contents of the alga exceeded 30% of its dry cell weight, with palmitic acid and DHA as the most abundant components. When the effect of a single additive was concerned, meat extract was significantly effective, while interaction between meat extract and glucose was the most effective in comparison with other interactions (P < 0.0001). According to the results, glucose can assure more algal and fatty acids production when adequate amounts of meat extract exist in the culture medium. Optimal results attained when the ratios of glucose to meat extract and C/N concentrations were 10 and 5, respectively. Due to its remarkable growth rate and the capability to produce substantial quantities of biomass and fatty acids, Aurantiochytrium sp.shy was found to be a major source of the beneficial ingredients, whose productivity can magnify if its culture conditions is optimized using favorable blend of growth-promoting materials.
 

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  One of the most important researches areas in food industry is setting parameters in an optimal level to improve process functions. A literature research in food science and technology databases reveals that in recent years many optimization methods have been developed to improve food processing. However, most of these methods have only dealt with a single objective problem. In many situations the quality of a manufactured product is often evaluated by several quality characteristics and multiple objectives must be optimized simultaneously. In this article we propose a method that integrates design of experiments, response surface technique and Signal-to-Noise (SN) ratio concept for optimization of a kind of yoghurt, called Whey Less, with three objectives: TS, Acidity and cost per unit. The proposed method considers both the mean and the variation of quality losses associated with several objectives, and ensures a small variation in quality losses among the objective functions, along with a small overall average loss. Moreover, this method can be used for both kinds of decision variables (discrete and continuous) and its implementation is easy.  

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Bread is the basic food group and it is one of the best sources of protein and energy especially for low income people. So it is important to pay attention to the characteristics that affect bread quality. One of the main factors affecting the quality of bread is the quality of gluten. Low quality of gluten in flour will make problems in bread industry. One solution to these problems is using the combination of glucose oxidase and xylanase enzymes. In this research, central composite design has been used to evaluate the effects of these enzymes as independent parameters on rheological characteristics of dough measured by Alveograph. The specific volume and sensory evaluation of bread has been determined after bread baking. Results showed that adding these enzymes lead to increase pressure and energy of dough and decrease in dough strength. After baking, results indicated increase in specific volume and total score in sensory evaluation of the breads in compare with the bread containing only α- amylase enzyme. In this research 35 ppm of glucose oxidase and 15 ppm of xylanase were selected as the best treatment after optimizing results by response surface method.  

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From 1999 and 2000, DAG oil production has been started in Japan and USA. It must be mentioned that DAG oil has been considered as useful product for human health and it is known as functional and nutraceutical cooking oil. The objective of this study was to evaluate reaction parameters in DAG production from safflower oil and to optimize the process to obtain maximum yield of DAG. After safflower oil extraction, enzymatic glycerolysis was used to produce DAG oil. The treatments were determined using Design-expert software and after modeling, the process optimization was done. Finally, some physicochemical properties of DAG oil were investigated. After modeling, it was observed that the enzyme load had linear effect while the reaction temperature and glycerol content showed the quadratic effect on DAG yield. Also it was obtained that there was significant interaction effect between enzyme load/time, enzyme load/ glycerol and time/glycerol. Results showed that there was no significant difference between DAG and safflower oils in terms of specific gravity and iodine value but refractive index, color and peroxide value were different. Maximum production of DAG (48.454 %) obtained at reaction temperature of 46.9 ^ºC, reaction time of 4 h, enzyme load of 0.75 % (weight of oil), and molar ratio of glycerol to oil 2:1 which was increased to 53.84 % after product purification.  

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In this research, the culture condition improvement on phytase productionby Aspergillus ficuum PTCC 5288 was investigated using submergedfermentation method in 250 ml shake flask. Four factors which influencing phytase production, including carbon source (glucose) in five level (2, 3.5, 5, 6.5 and 8 g/100 mL), nitrogen source (ammonium sulphate) five levels (1, 2, 3, 4 and 5 g/100 mL), phosphor source (wheat bran) five levels (1, 2, 3, 4 and 5 g/100 mL),and fermentation time five levels (48, 120, 192, 264 and 336 hour) were studied. The optimum levels of these significant factors were determined via response surface methodological approach as: 5.23g/100 mL glucose, 1.6 g/100 mL ammonium sulphate, 3.28 g/100 mL glucose wheat branand198.30 hours.The maximum predicted amount of phytase was 39.61 U/mL and the produced amount of phytase under these conditions was 40.21 U/mL, which indicates the efficacy of the model for prediction of phytase production content under different conditions of the medium.  

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In this reasearch, optimal condition on oil and arachidonic acid production by mortierella alpina CBS 754.68 was investigated using response surface methodology. Tow factors which influencing arachidonic acid and oil production; including carbon source (glucose) in five levels (45.8, 50, 60, 70 and 74.14 gl) and nitrogen source (soybean meal) in five levels (7.92, 10, 15, 20 and 22.07 gl) were studied. Arachidonic acid and oil yield varied msignificantly in response to changes in concentration of soybean meal and glucose. The model predicted that, maximum production of AA (that is, up to %56.40) and oil (that is, up to %50.13) could be achieved using the medium containing (glucose 50.35 and soybean 18.30 gl) and (glucose 70 and soybean 10 gl), respectively. In the next stage change the medium composition and biomass during fermentation was investigated in two medium optimized. The results showed that oil and arachidonic acid production significant increase with fungi and storage oil stopped respectively. Phenolic compounds are directly related with cell growth rate and the amount of fungi oil.  

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Hyaluronic acid (HA) is a natural and linear polymer that finds a wide-range of applications in medicine, cosmetics, and nutraceuticals because of excellent viscoelasticity, high moisture retention capacity, high biocompatibility and non-toxicity. HA has been recently produced in industrial scale by Streptococcal species. Streptococci are nutritionally fastidious lactic acid bacteria and cannot synthesize some amino acids. Therefore, it is necessary to study and select some commercial culture media for their growth. In this study, HA production and hyaluronidase activity of S. zooepidemicus ATCC 43079 in three culture media were investigated. Regarding the detrimental effect of this enzyme on HA amount, 6-O-Palmitoyl-L-ascorbic acid as hyaluronidase inhibitor was added to culture medium during fermentation. The effect of three variables consisted of glucose concentration, yeast extract concentration and medium pH each at 3 levels were considered and (response surface methodology (RSM) was used for statistical design of experiments to study the HA production by this strain. The results showed that maximum HA production was obtained when glucose concentration, yeast extract concentration and pH were 21.2 g L^-1, 43.6 g L^-1 and 6.6, respectively. Under optimum conditions, HA was produced as 370±15 mg L^-1 which was ~150% more than of HA concentration in basal medium (150±10 mg L^-1) and productivity reached 56.74 g L^-1 h^-1 that was increased 2 fold compared to central point.