响应面法优化海藻酸盐复合凝胶微球的制备工艺条件

以氯化钙(CaCl2)和壳聚糖(CS)作为交联体系,膨润土(BT)作为吸附剂制备了负载甲氨基阿维菌素苯甲酸盐的海藻酸盐(SA)复合凝胶微球,以其载药率(DLR)和平衡溶胀率(ESR)的比值作为响应值(UR,UR=DLR/ESR),采用Box-Behnken设计建立模型和考察海藻酸钠质量分数(1.00~3.00 wt.%)、膨润土质量分数(1.00~5.00 wt.%)、氯化钙浓度(0.10~0.40 mol/L)和壳聚糖质量分数(0.50 ~1.50 wt.%)对响应值的影响。结果表明响应值与四因素关系符合二次模型,在实验范围内,该数学回归模型具有良好的预测性。在各因素设定范围内预测最佳工艺条件为：海藻酸钠浓度2.39 wt.%、膨润土浓度2.81 wt.%、氯化钙浓度0.24 mol/L、壳聚糖浓度0.71 wt.%。在该条件下进行3次重复实验,实际测得的平均响应值为3.5509%,与理论预测值3.5836%无显著性差异。在该条件下制备的复合凝胶微球,包封率为98.31%,载药率为2.11%,并且具有良好的缓释性能。     

Immobilization of Phospholipase C for the Production of Ceramide from Sphingomyelin Hydrolysis

The immobilization of Clostridium perfringens phospholipase C was studied for the first time and the catalytic properties of the immobilized enzyme were investigated for the hydrolysis of sphingomyelin to produce ceramide. Ceramide is of great commercial value in the cosmetic and pharmaceutical industries for use in, for example, hair and skin care products, owing to its major role in maintaining the water-retaining properties of the epidermis. The feasibility of enzymatic production of ceramide through hydrolysis of sphingomyelin has previously been proven. In order to improve the reusability of the enzyme, the present study focused on the immobilization of phospholipase C in the production of ceramide from sphingomyelin. By screening nine different carriers, we found that the enzyme immobilized on Lewatit had the highest catalytic activity towards sphingomyelin hydrolysis. Prewetting Lewatit with ethanol led to higher enzyme fixation on the carrier, but the activity of the enzyme was decreased. Increasing the initial enzyme concentration resulted in more enzyme adsorption on the carrier, where the specific activity was increased. Through optimization of the reaction using the immobilized enzyme, the optimal temperature was around 46 °C and the optimal water volume was 3.5%. The reaction had little dependence on pH. After seven recycles, immobilized enzyme retained around 70% of the initial activity. Immobilized enzyme was deactivated irregularly when stored at room temperature, but followed first-order deactivation when stored at 40 °C.     

Effects of Drying Methods on the Release Kinetics of Vitamin B12 in Calcium Alginate Beads

The aim of this article was to investigate the morphology, swelling properties, and respective drug release kinetics of vitamin B₁₂–loaded calcium alginate beads prepared by oven (air), vacuum, and freeze drying. The initial particle size was 1 mm. The mean bead sizes of dried Ca-alginate beads were 0.7, 0.8, and 0.9 mm for oven-, vacuum-, and freeze-dried beads, respectively. The surface morphology of the dried beads was affected by the different drying methods applied. Oven- and vacuum-dried beads shrank in size, and more cracks appeared on the surface of oven-dried beads. Freeze-dried beads almost retained the same size prior to drying; however, the surface was rougher and highly porous. The swelling profiles were also affected by the drying methods, whereby freeze-dried beads showed the fastest solvent uptake at the start of the experiment. The release data of the dried Ca-alginate beads were treated with first-order, Higuchi, Korsmeyer, and Peppas kinetic models. The data for oven and vacuum seemed to follow a combination of diffusion and swelling controlled release, whereas data from freeze-dried beads seemed to follow more diffusion-dominated controlled release.     

Continuous Production of Uniform Calcium Alginate Beads by Sound Wave Induced Vibration

A new process for the immobilization of sodium alginate, which employs a vibration of membrane induced by sound waves from a horn-type speaker, is developed to produce uniformly-sized beads of predictable diameter. Frequency of sound wave and production rate are varied to find the optimal control ranges for the bead production. The controllable bead size range is 1·50–3·50 mm and the experimental production rates are 0–12 dm³ h^-1 by a single nozzle. This method of bead production is a practical alternative to conventional continuous bead production methods with low apparatus cost and easier and better control of bead size and shape.     

海藻酸钙凝胶固定葡萄糖氧化酶的研究

利用海藻酸钙凝胶颗粒固定葡萄糖氧化酶(GOD).确定了固定化条件,并考察了温度、pH值、储存时间对固定化酶和游离酶酶活力的影响,测定了酶活回收率.确定的固定化较优条件为:CaCl2 5.0%(质量体积比),海藻酸钠3.0%(质量体积比);固定化酶的最适催化温度为31℃、最适pH值为6.3,较游离酶分别提高7℃和0.6;固定化酶的平均酶活回收率为61.69%.此外,酶的储存稳定性能也有所提高,可重复多次使用.     

Thermomechanical and Interfacial Properties of Calcium Alginate Fiber-Reinforced Polypropylene Composites

Polypropylene (PP) matrix calcium alginate fiber reinforced unidirectional composites (10% fiber by weight) were fabricated by compression molding. Tensile strength (TS), tensile modulus (TM), bending strength (BS), bending modulus (BM), and impact strength (IS) were found to be 26 MPa, 950 MPa, 38 MPa, 1320 MPa, and 20 kJ/m², respectively. Degradation tests of composites were performed for 6 weeks in soil and it was found that composites retained almost 75% of its original strength. The interfacial properties of the composite were investigated by using single fiber fragmentation test (SFFT) and by scanning electron microscope (SEM).     

Optimization of Food Waste Bioevaporation Process Using Response Surface Methodology

A proven bioevaporation process was used to treat food waste (FW) by mixing ground FW with biodried sludge (BS). Organic loading (OL), moisture content (MC), and air flow rate (Q_g) showed significant influences on FW bioevaporation performance. Single-parameter experiments for MC and Q_g were conducted and ranges were determined to be 55–67 wt% and 0.04–0.14 m³/kg TS_mixture · h, respectively. In order to optimize the FW bioevaporation process, a central composite design (CCD) and response surface method (RSM) were applied over the preselected ranges of OL (0.00–0.16 kg VS_FW/kg TS_BS), MC (50.91–71.09 wt%), and Q_g (0.01–0.17 m³/kg TS_mixture · h). The results indicated that OL of 0.06 kg VS_FW/kg TS_BS, MC of 59.2 wt%, and Q_g of 0.09 m³/kg TS_mixture · h were the optimal conditions for the FW bioevaporation process. Water evaporation of 123.1% and VS degradation of 108.4% were obtained under these estimated optimal conditions.     

Optimization of supercritical dimethyl carbonate (SCDMC) technology for the production of biodiesel and value-added glycerol carbonate

In the present study, biodiesel has been successfully produced from triglycerides and dimethyl carbonate, instead of the conventional alcohol. In this non-catalytic supercritical dimethyl carbonate (SCDMC) technology, valuable compound of glycerol carbonate is obtained as side product, rather than the undesirable glycerol. Glycerol carbonate has higher commercial value compared to glycerol and its application in industries is enormous. In this optimization study, the effects of important parameters including reaction temperature, molar ratio of dimethyl carbonate to oil and reaction time were investigated and optimized by employing response surface methodology (RSM) analysis. It was found that the mathematical model developed was statistically significant and adequate to predict the optimum yield. The optimum conditions for SCDMC process was found to be 380 °C for reaction temperature, 39:1 mol/mol of dimethyl carbonate to oil molar ratio and 30 min of reaction time to obtain 91% optimum yield of biodiesel.     

海藻酸钙微胶囊的制备

研究了海藻酸钙微胶囊的制备条件和影响因素。试验结果表明 :海藻酸钠浓度不宜超过 3.0 % ,Ca Cl2的浓度为 1.0 %～ 4 .0 % ,适宜转速为 30 0 r· min- 1 ,下滴速率可控制在 6 0～ 90滴· m in- 1 ,成型的微胶囊浸泡在蒸馏水中存放 30 d后变化不大     

Optimization of Vegetal Pear Drying Using Response Surface Methodology

The aim of this work was to optimize the drying process of vegetal pear and minimize energy resources (cost) under prefixed limits involving vegetal pear moisture, color, and productivity. The optimization of vegetal pear drying was made by using response surface methodology (RSM) for minimum process cost and color difference between fresh and dried samples (moisture ≤0.10 g water g d.m.^?1). A pilot-plant dryer was used for dehydrating vegetal pear slices (0.5 cm thickness). The tests were carried out at different air temperature (60 to 70°C), samples diameter (4 to 7 cm), and pretreatment with ascorbic acid solutions (0–0.1% w/w). The optimum drying conditions were found at air temperature of 63°C with 5-cm sample diameter and 0.075% of ascorbic acid concentration. On the optimized drying conditions, dried vegetal pear presented values with moisture content of 0.052 g water g d.m.^?1, color difference of 11.65, production rate of 0.0073 kg h^?1, and total cost of $30.58/kg dried product^?1     

Optimization of solar-powered reverse osmosis desalination pilot plant using response surface methodology

A solar thermal and photovoltaic-powered reverse osmosis (RO) desalination plant has been constructed and optimized for brackish water desalination. The central composite experimental design of orthogonal type and response surface methodology (RSM) have been used to develop predictive models for simulation and optimization of different responses such as the salt rejection coefficient, the specific permeate flux and the RO specific performance index that takes into consideration the salt rejection coefficient, the permeate flux, the energy consumption and the conversion factor. The considered input variables were the feed temperature, the feed flow-rate and the feed pressure. Analysis of variance (ANOVA) has been employed to test the significance of the RSM polynomial models. The optimum operating conditions have been determined using the step adjusting gradient method. An optimum RO specific performance index has been achieved experimentally under the obtained optimal conditions. The RO optimized plant guarantees a potable water production of 0.2 m³/day with energy consumption lower than 1.3 kWh/m³.     

Optimization of Parameters for Microwave-Assisted Foam Mat Drying of Blackcurrant Pulp

Both analysis and optimization of parameters of microwave-assisted foam mat drying (MAFM), viz. microwave power, pulp load, drying time, and pulp thickness, for the dehydration process of blackcurrant pulp were performed in a household microwave oven. During MAFM drying, microwave power, pulp load, and drying time have positive effects on both vitamin C and anthocyanin content of blackcurrant pulp up to a certain level then a negative trend is observed. The increase of microwave power and decrease of pulp load accelerate the dehydration of blackcurrant pulp. The pulp thickness has a significant positive effect on both vitamin C and anthocyanin content of blackcurrant pulp. The optimum parameters valid for MAFM drying of blackcurrant pulp are as follows: microwave power of 560 W, pulp load of 65 g, drying time of 8 min, and pulp thickness of 4.46 mm. MAFM drying is a potential method for dehydrating blackcurrant pulp.     

Optimization of crude oil dehydration in an industrial spiral-type gravitational coalescer

This research is focused on modelling and optimization of crude oil dehydration in a spiral-type gravitational coalescer process. The process is modelled based on the population balance to calculate water cut and droplet size distribution in the treated crude oil. The effects of fresh water rate, oil temperature and mixing pressure drop on characteristics of treated crude oil are investigated using response surface methodology. The optimum condition of process is determined considering output water cut, salt content and produced gas in gravitational coalescer as objective functions. The results show that water cut in the treated crude oil is decreased about 21.2% at optimal condition.     

Optimization of Drying of Olive Leaves in a Pilot-Scale Heat Pump Dryer

Recently, the interest in olive leaf has increased due to its high phenolic content. It has a high potential for industrial exploitation in food industry and the main process in olive leaf treatment is drying. Drying affects the product quality and is an energy-intensive process, so the use of heat pumps in drying processes that have low operating cost has attracted the attention of the investigators. In this study, response surface methodology was used to optimize operating conditions of drying of olive leaves in a pilot-scale heat pump conveyor dryer. The independent variables were air temperature, air velocity, and process time, and the responses were total phenolic content and antioxidant activity loss, final moisture content, and exergetic efficiency. Optimum operating conditions were found to be temperature of 53.43°C, air velocity of 0.64 m/s, process time of 288.32 min. At this optimum point, total phenolic content loss, total antioxidant activity loss, final moisture content, and exergetic efficiency were found to be 9.77%, 44.25%, 6.0% (w.b.), and 69.55%, respectively.     

Optimization of Phospholipid Nanoparticle Formulations Using Response Surface Methodology

The present study deals with the optimization of phospholipid liposome formulations to mimic red blood cells. Optimization of different concentrations of distearylphosphatidylcholine, dipalmitoylphosphatidylcholine, and phosphatidylserine at a fixed concentration of lecithin and Tween^® 80 was done using response surface methodology. The optimized formulation produced liposomes with a particle size in the range of 112–196 nm. The optimized formulation shows low encapsulation efficiency at low levels of insulin but increases at higher loading levels. Formulated vesicles fulfill the size requirement for intravenous drug delivery. The present system is environmentally friendly with respect to biodegradability and biocompatibility.     

Optimization of Rubber Wood Drying by Response Surface Method and Multiple Contour Plots

Abstract

By adopting the central-composite experiment design, the response surface methodology was used to optimize operating conditions of rubber wood drying. The independent variables are initial moisture content of rubber wood, and three drying environment parameters namely, temperature, relative humidity, and air velocity. The investigating responses are final moisture content, drying time, and energy consumption. The restriction of the optimization is the designated final moisture content, which is not greater than 16%. The third-order polynomial models with transformed responses were developed from experiment data to generate 3-D response surfaces and contour plots. The analysis of variance (ANOVA) was performed to identify the significant parameters affecting the rubber wood drying. Drying temperature and holding relative humidity are those two influential operating parameters that significantly control the final moisture of rubber wood and affect the drying time and energy. The multiple contour plots of drying responses show that the optimum operating regions are located mainly at high temperature drying zone. The high temperature drying practice can save energy and drying time by 44 and 25% respectively, in comparison to the conventional temperature drying.     

Optimization of Rubber Wood Drying by Response Surface Method and Multiple Contour Plots

By adopting the central-composite experiment design, the response surface methodology was used to optimize operating conditions of rubber wood drying. The independent variables are initial moisture content of rubber wood, and three drying environment parameters namely, temperature, relative humidity, and air velocity. The investigating responses are final moisture content, drying time, and energy consumption. The restriction of the optimization is the designated final moisture content, which is not greater than 16%. The third-order polynomial models with transformed responses were developed from experiment data to generate 3-D response surfaces and contour plots. The analysis of variance (ANOVA) was performed to identify the significant parameters affecting the rubber wood drying. Drying temperature and holding relative humidity are those two influential operating parameters that significantly control the final moisture of rubber wood and affect the drying time and energy. The multiple contour plots of drying responses show that the optimum operating regions are located mainly at high temperature drying zone. The high temperature drying practice can save energy and drying time by 44 and 25% respectively, in comparison to the conventional temperature drying.     

Optimization of Microwave-Vacuum Drying of Button Mushrooms Using Response-Surface Methodology

Button mushrooms (Agaricus bisporous) were dried in a microwave-vacuum dryer up to a final moisture content of around 6% (d.b.). The effect of microwave power level (115 to 285 W), system pressure (6.5 to 23.5 kPa), and slice thickness (6 to 14 mm) on drying efficiency and some quality attributes (color, texture, rehydration ratio, and sensory attributes) of dehydrated mushrooms were analyzed by means of response surface methodology. A rotatable central composite design was used to develop models for the responses.Analysis of variance showed that a second-order polynomial model predicted well the experimental data. The system pressure strongly affected color, hardness, rehydration ratio, and sensory attributes of dehydrated mushrooms. A lower pressure during drying resulted in better quality products. Optimum drying conditions of 202 W microwave power level, 6.5 kPa pressure, and 7.7 mm slice thickness were established for microwave vacuum drying of button mushrooms. Separate validation experiment was conducted at the derived optimum conditions to verify the predictions and adequacy of the models.     

Modeling and Optimization of Reactive Extraction of Gallic Acid Using RSM

Reactive extraction was experimentally investigated for recovery of gallic acid (GA) from the aqueous solution using tri-n-octylamine (TOA) as extractant in hexanol. All experiments were carried out according to statistical design in order to develop a regression model used to optimize the extraction of GA. Two independent variables were selected as: initial concentration of GA (C_GA0) in aqueous phase and concentration of TOA (C_TOA) in organic phase. The statistical analysis showed that both the independent variables had significant effect on response value, followed by the quadratic and interactive effect on response. A five-level central composite rotatable design (CCRD) was employed. Analysis of variance (ANOVA) showed a high coefficient of determination (R²?=?99.0%). The optimal extraction conditions of GA were determined as: C_GA0?=?2.01?g/L, C_TOA?=?6.8% v/v. At the optimum conditions, the experimental yield of GA was 91.9%, which was in close agreement with the predicted value of 93.2%.     

Optimization and mechanisms analysis of indigo dye removal using continuous electrocoagulation

Electrocoagulation (EC) is among the most effective techniques that remove color and decontaminate effluent. Coagulants are delivered in situ by anode corrosion. In this research, indigo dye removal using iron electrodes in continuous electrocoagulation process and the responsible species for decolorization were investigated. The Response Surface Methodology (RSM) was used to optimize the process parameters. The finding in this study shows that at fixed conductivity at 15,000 μS·cm^-1, the neutral conditions (pH from 6 to 8), the low absorbance, the low flow rate and the high voltage level enhance the color removal efficiency. The high R² value of 97.8% and ANOVA analyses show a good correlation between the experimental and predicted results. Under the optimum conditions, which are pH of 7.5, solution concentration of 60 mg·L^-1, inlet flow rate of 2 L·min^-1 and voltage of 47 V, the predicted decolorization of 94.083% was achieved at 93.972% with a total cost of 0.0927 USD·m^-3 of treated effluent. At the optimum pH (7.5), the zeta potential value (-4 mV) of the effluent during EC match with the one of iron Ⅲ hydroxide. The dye removal is ensured thanks to physical adsorption and flocculation. The results exposed in this work prove that the continuous electrocoagulation process could be successfully used for indigo dye removal at industrial scale.