Optimization of ultrasound-assisted extraction of anthocyanins from mulberry, using response surface methodology

Mulberry is one of the most widely used traditional Chinese medicines. Anthocyanins are the main bioactive components of mulberry, and possess important biological activities, such as antimicrobial, anti-inflammatory and antioxidant activities. This study investigated the ultrasound-assisted extraction (UAE) of anthocyanins from mulberry by using response surface methodology (RSM). The extraction conditions associated with anthocyanin yield, including extraction solvent, liquid-to-solid rate, temperature and extraction time, are discussed. The optimal conditions obtained by RSM for UAE from mulberry include 63.8% methanol contains 1% (v/v) trifluoroacetic acid (TFA), 43.2 °C temperature, 23.8 (v/w) liquid-to-solid ratio, and 40 min time for the maximum yield (64.70 ± 0.45 mg/g). The results indicated that the UAE can be an effective method for the extraction of some active components from plant materials.     

响应曲面法优化超声辅助提取油菜籽皮中的原花青素

以乙醇为提取剂,用超声辅助的方法从油菜籽皮中提取了原花青素。在讨论了提取剂体积分数、提取时间、液料比(每克原料加入提取剂的毫升数,简称液料比,以下同)和超声波功率等单因素实验的基础上,运用Box-Behnken中心组合实验和响应曲面法分析了提取剂体积分数、提取时间和液料比3个因素对原花青素提取率的影响,并优化了提取工艺。结果表明,最佳的工艺条件为:乙醇体积分数62.9%,提取时间20.8 min,液料比25 mL/g。在该条件下,原花青素提取率的预测值为5.055 mg/g,验证实验值为5.02 mg/g,说明响应曲面法优化油菜籽皮中原花青素提取工艺是可行的。     

Sulfur removal from hydrotreated petroleum fractions using ultrasound-assisted oxidative desulfurization process

Ultrasound-assisted oxidative desulfurization (UAOD) process was applied to diesel oil and petroleum product feedstock containing model sulfur compounds (benzothiophene, dibenzothiophene and dimethyldibenzothiophene). The influence of oxidant amount, volume of solvent for the extraction step and time and temperature of ultrasound treatment (20 kHz, 750 W, operating at 40%) was investigated. Using the optimized conditions for UAOD, sulfur removal up to 99% was achieved for model compounds in petroleum product feedstock using a molar proportion for H₂O₂:acetic acid:sulfur of 64:300:1, after 9 min of ultrasound treatment at 90 °C, followed by extraction with methanol (optimized solvent and oil ratio of 0.36). Using the same reagent amount and 9 min of ultrasound the removal of sulfur was higher than 75% for diesel oil samples. Sulfur removal without ultrasound using the same conditions was lower than 82% for model compounds and 55% for diesel oil samples showing that ultrasound improved the efficiency of oxidative desulfurization. In comparison to conventional hydrodesulfurization, the proposed UAOD process can be performed under relatively mild conditions (atmospheric pressure and 90 °C, without using metallic catalysts).     

Response surface methodology approach to optimize coagulation-flocculation process using composite coagulants

Response surface method and experimental design were applied as alternatives to the conventional methods for optimization of the coagulation test. A central composite design was used to build models for predicting and optimizing the coagulation process. The model equations were derived using the least square method of the Minitab 16 software. In these equations, the removal efficiency of turbidity and COD were expressed as second-order functions of the coagulant dosage and coagulation pH. By applying RSM, the optimum condition using PFPD₁ was coagulant dosage of 384 mg/L and coagulation pH of 7.75. The optimum condition using PFPD₂ was coagulant dosage of 390 mg/L and coagulation pH of 7.48. Confirmation experiment demonstrated a good agreement between experimental values and model predicted. This demonstrates that RSM and CCD can be successfully applied for modeling and optimizing the coagulation process using PFPD₁ and PFPD₂.     

响应面法优化阴香籽油制备生物柴油的研究

在单因素的基础上,通过响应面法优化阴香籽油制备生物柴油的工艺条件。结果表明,阴香籽油制备生物柴油的优化工艺条件为:油醇摩尔比1∶6.5,催化剂用量为油质量的1.0%,反应时间125 min,反应温度61℃,理论转化率为92.79%。实际验证值为93.10%。以阴香籽油为原料通过酯化反应制取的生物柴油与0#柴油及国标GB/T20828—2007主要性能相似,阴香籽油生物柴油可以全部或部分替代0#柴油,是一种安全的可再生绿色生物能源。     

响应面法优化阴香籽油制备生物柴油的研究

在单因素的基础上,通过响应面法优化阴香籽油制备生物柴油的工艺条件。结果表明,阴香籽油制备生物柴油的优化工艺条件为:油醇摩尔比1∶6.5,催化剂用量为油质量的1.0%,反应时间125 min,反应温度61℃,理论转化率为92.79%。实际验证值为93.10%。以阴香籽油为原料通过酯化反应制取的生物柴油与0#柴油及国标GB/T20828—2007主要性能相似,阴香籽油生物柴油可以全部或部分替代0#柴油,是一种安全的可再生绿色生物能源。     

响应面法优化鹿血肽的制备工艺

采用碱性蛋白酶水解鹿血蛋白制备鹿血肽.应用响应面分析法选取温度、时间、pH值、酶量4个主要因素,以水解率为响应值,对其工艺进行了优化.得出了鹿血蛋白水解的最佳工艺条件为:温度(53％)、时间(5.5h)、pH(9.5)、酶量(1272U·g-1),在此条件下鹿血的实际水解率为22.13％.实验证明响应面法对鹿血肽的制备...     

响应面法优化PDS脱硫过程的吸收工艺

采用现场脱硫液,在填料塔内模拟实际PDS(酞菁钴磺酸盐)脱硫工艺中吸收H_2S的过程,通过试验测定了总传质系数KG。采用单因素试验分别考察了流体和气体流量对传质系数的影响,确定了适宜的液体和气体流量范围。在此基础上设计了响应面法的因素和水平,进行了试验。采用响应面法拟合了试验结果,分析了喷淋密度、气速和Na_2CO_3质量浓度对KG的影响。结果表明:KG随喷淋密度和Na_2CO_3质量浓度的增加而增加,其中Na_2CO_3质量浓度对KG的影响最显著。随着气速的增加,KG总体呈先增大后减小的趋势。当气速为0.101 9 m/s、喷淋密度为20.51 m~3/(m~2·h)、脱硫液中Na_2CO_3质量浓度9 g/L时,KG达到最大值0.002 4 kmol/(m~2·h·kPa)。     

响应面法优化污泥厌氧消化液的化学除磷研究

剩余污泥厌氧消化液中含有丰富的磷,是磷回收的重要来源之一。采用Box-Benhnken中心组合试验原理和响应面分析法,研究了以铝盐为除磷剂回收厌氧消化液中磷源的过程中,Al∶P比、快速搅拌强度和反应时间等因素对除磷率的影响。结果表明,最佳铝盐除磷条件:Al∶P摩尔比1.70,快速搅拌强度300 r/min,慢速搅拌强度45 r/min,反应20 min,沉淀20 min。在此条件下,可实现剩余污泥厌氧消化液中93.41%的磷回收率。     

响应面法优化污泥厌氧消化液的化学除磷研究

剩余污泥厌氧消化液中含有丰富的磷,是磷回收的重要来源之一。采用Box-Benhnken中心组合试验原理和响应面分析法,研究了以铝盐为除磷剂回收厌氧消化液中磷源的过程中,Al∶P比、快速搅拌强度和反应时间等因素对除磷率的影响。结果表明,最佳铝盐除磷条件:Al∶P摩尔比1.70,快速搅拌强度300 r/min,慢速搅拌强度45 r/min,反应20 min,沉淀20 min。在此条件下,可实现剩余污泥厌氧消化液中93.41%的磷回收率。     

Utilization of response surface methodology to optimize the culture media for the production of rhamnolipids by Pseudomonas aeruginosa AT10

Pseudomonas aeruginosa AT10 produced a mixture of surface‐active rhamnolipids when cultivated on mineral medium with waste free fatty acids as carbon source. The development of the production process to an industrial scale included the design of the culture medium. A 2⁴ full factorial, central composite rotational design and response surface modelling method (RSM) was used to enhance rhamnolipid production by Pseudomonas aeruginosa AT10. The components that are critical for the process medium were the carbon source, the nitrogen source (NaNO₃), the phosphate content (K₂ HPO₄/KH₂PO₄ 2:1) and the iron content (FeSO₄·7H₂O). Two responses were measured, biomass and rhamnolipid production. The maximum biomass obtained was 12.06 g dm^?3 DCW, when the medium contained 50 g dm^?3 carbon source, 9 g dm^?3 NaNO₃, 7 g dm^?3 phosphate and 13.7 mg dm^?3 FeSO₄·7H₂O. The maximum concentration of rhamnolipid, 18.7 g dm^?3, was attained in medium that contained 50 g dm^?3 carbon source, 4.6 g dm^?3 NaNO₃, 1 g dm^?3 phosphate and 7.4 mg dm^?3 FeSO₄·7H₂O. © 2002 Society of Chemical Industry     

Application of response surface methodology to optimize the operation process for regeneration of acid and base using bipolar membrane electrodialysis

BACKGROUND: Bipolar membrane electrodialysis (BMED) has been widely used for desalination, concentration, separation, and purification in many fields. The purpose of this study is to optimize the operation conditions using response surface methodology (RSM) for the regeneration of sulfuric acid and ammonia from ammonium sulfate solution by BMED coupled with ammonia in situ stripping. RESULTS: A three‐factor central composite design of RSM was used to analyze the effect of operation conditions (current density, flow rate, initial acid concentration) on average current efficiency (ACE) and establish the optimal operation conditions. The ACE was 76.7 ± 2.2% under optimal operation conditions (current density 23.8 mA cm^?2, flow rate 27.3 L h^?1, initial acid concentration 0.09 mol L^?1). CONCLUSION: A suitable regression model for predicting ACE within the ranges of variables used was developed based on experimental results. The operation conditions were optimized by RSM and the ACE obtained under the optimal operation conditions was in good agreement with the value predicted by the regression model (78%), which proved the validity of the model. Copyright © 2007 Society of Chemical Industry     

Process optimization of oxidative coupling of methane for ethylene production using response surface methodology

The statistical design of experiments (DoE) was used in the process study of oxidative coupling of methane (OCM) over Na? W? Mn/SiO₂ catalyst. A set of factors with a certain range was screened using factorial design with respect to three responses: methane conversion, C₂₊ products selectivity and ethylene/ethane ratio. The variances were analyzed and the interaction effects of the process parameters were evaluated. With the understanding of the process, the optimization of the process was further studied using response surface methodology coupled with central composite design (CCD). The optimum conditions were obtained as reaction temperature = 850 °C, gas hourly space velocity = 23 947 cm³ g^?1 h^?1, catalyst pretreatment period = 2 h, dilution ratio = 0.2 and CH₄/O₂ ratio = 7. 40.55% of methane conversion and 79.51% of C₂₊ product selectivity were obtained under these optimum conditions. Experimental runs under optimum conditions were repeated and compared with the simulated values obtained from the model. There was good agreement between the experimental and simulated values. Copyright © 2007 Society of Chemical Industry     

Use of surface response methodology to optimize culture conditions for iturin A production by Bacillus subtilis in solid-state fermentation

Response surface methodology (RSM) was employed to optimize the cultivation conditions of Bacillus subtilis S3 for the enhancement of iturin A, a lipopeptide antibiotic used as biological pesticide, production in solid-state fermentation (SSF). The statistic experimental model predicted a maximum iturin production of 11.435 mg/g-wet solid material. Verification of the calculated maximum was done with experiments that were performed in the culture media representing the optimum combination found, and the iturin A production of 11.447 mg/g-wet solid material (average of three repeats) was obtained when B. subtilis S3 was cultivated at 25 °C for 5 days in solid fermentation containing high gluten flour 10 g and rice bran 50 g in addition to glucose 1.15%, KH₂PO₄ 1.27 mM, MgSO₄ 5.08 mM, peanut oil 1.01%, inoculum 19.49% and water content 44.97%. The iturin A production by B. subtilis S3 was increased significantly by 23%, from 9.26 mg/g-wet solid material to 11.447 mg/g-wet solid material when the strain was cultivated in the optimal medium developed by surface response methodology, as compared to medium conventionally developed by one-factor-at-a-time. The yield of iturin A (11.447 mg/g-wet solid material, with 45% moisture content) produced by B. subtilis S3 reported in this study is the highest reported to date for B. subtilis species in SSF. In addition, the use of rice bran as a substrate in solid-state fermentation for iturin A production by B. subtilis is unique.     

Using bipolar membrane electrodialysis to synthesize di-quaternary ammonium hydroxide and optimization design by response surface methodology

Bipolar membrane electrodialysis (BMED) has already been described for the preparation of quaternary ammonium hydroxide.However,compared to quaternary ammonium hydroxide,di-quaternary ammonium hydroxide has raised great interest due to its high thermal stability and good oriented performance.In order to synthesize N,N-hexamethylenebis(trimethyl ammonium hydroxide) (HM(OH)2) by EDBM,experiments designed by response surface methodology were carried out on the basis of single-factor experiments.The factors include current density,feed concentration and flow ratio of each compartment (feed compartment:base compartment:acid compartment:buffer compartment).The relationship between current efficiency and the above-mentioned three factors was quantitatively described by a multivariate regression model.According to the results,the feed concentration was the most significant factor and the optimum conditions were as follows:the current efficiency was up to 76.2％ (the hydroxide conversion was over 98.6％),with a current density of 13.15 mA·cm-2,a feed concentration of 0.27 mol· L-1 and a flow ratio of 20 L· h-1∶26 L· h-1 ∶20 L· h-1∶20 L· h-1 for feed compartment,base compartment,acid compartment,and intermediate compartment,respectively.This study demonstrates the optimized parameters of manufacturing HM(OH)2 by direct splitting its halide for industrial application.     

响应面法优化氧化锌中高温煤气脱硫剂的制备工艺

通过优化制备工艺和制备条件,提高氧化锌脱硫剂的脱硫性能。以乙二酸和乙酸锌为原料,采用固相法制备了乙二酸锌前驱体;添加助剂和粘结剂后,通过微波焙烧制备了氧化锌中高温煤气脱硫剂。采用单因素法研究了微波功率、焙烧温度、焙烧时间以及活性组分质量分数对脱硫剂性能的影响,并利用响应面法探讨了各因素及其交互作用对脱硫剂穿透时间和硫容的影响,确定了氧化锌脱硫剂的最佳制备工艺:微波功率1 300 W,焙烧温度550℃,焙烧时间60 min,活性组分质量分数30%。采用回归分析法建立了回归模型,并通过试验验证了模型的可靠性。结果表明:模型预测值与实测值接近;焙烧温度、焙烧时间和活性组分质量分数对脱硫剂穿透时间有显著的影响;焙烧温度和焙烧时间、焙烧温度和活性组分质量分数二者的交互作用均比较显著。     

Application of response surface methodology for the optimization of supercritical carbon dioxide extraction and ultrasound-assisted extraction of Capparis spinosa seed oil

Caper (Capparis spinosa) seed oil growing wild in Iran was extracted using supercritical CO₂ and ultrasound-assisted extraction methods. The experimental parameters of SFE and UAE were optimized using a rotatable central composite design. The highest yield for SFE was obtained at a pressure of 355 bar, temperature of 65 °C, modifier volume of 140 μL, static and dynamic extraction time of 10 and 35 min, respectively, and for UAE was gained at solvent volume of 23 mL, sonication time of 45 min and temperature of 40 °C. This resulted in a maximum oil recovery of 25.1% and 27.9% for SFE and UAE, respectively. The extracts with higher yield from both methods were subjected to transesterification and GC–MS analysis. SFE and UAE processes selectively extracted the fatty oils with high percentage of omega-6 and omega-9-fatty acids. The major components of the extracted oils from both methods were linoleic, oleic, its positional isomer cis-vaccenic and Palmitic acid.     

Response surface methodology to optimize enzymatic preparation of deapio-platycodin d and platycodin d from radix platycodi

In the present work, we reported the enzymatic preparation of deapio-platycodin D (dPD) and platycodin D (PD) optimized by response surface methodology (RSM) from Radix Platycodi. During investigation of the hydrolysis of crude platycosides by various glycoside hydrolases, snailase showed a strong ability to transform deapio-platycoside E (dPE) and platycoside E (PE) into dPD and PD with 100% conversion. RSM was used to optimize the effects of the reaction temperature (35-45 °C), enzyme load (5-20%), and reaction time (4-24 h) on the conversion process. Validation of the RSM model was verified by the good agreement between the experimental and the predicted values of dPD and PD conversion yield. The optimum preparation conditions were as follows: temperature, 43 °C; enzyme load, 15%; reaction time, 22 h. The biotransformation pathways were dPE→dPD3→dPD and PE→PD3→PD, respectively. The determined method may be highly applicable for the enzymatic preparation of dPD and PD for medicinal purposes and also for commercial use.     

高炉水淬渣对电镀废水中重金属和COD吸附的响应面优化

为了考察高炉水淬渣处理实际电镀废水中重金属离子和COD的可行性,分别研究了吸附剂投加量、pH、吸附时间以及温度等单因素对Cu²⁺、Zn²⁺或COD去除率的影响。在单因素实验的基础上,应用 Box-Behnken中心组合方法进行三因素三水平试验,建立二次多项数学模型,并验证该模型的有效性。采用响应曲面法探讨吸附剂投加量、pH、吸附时间3个因子的交互作用及其最佳水平。结果表明：在吸附剂投加量为1.4g、pH为8、吸附时间为120min的最优化条件下,电镀废水中Cu²⁺、Zn²⁺和COD去除率达到最大,分别为99.35%、98.46%和53.63%。经对最优条件进行验证,预测值与验证实验平均值接近。吸附后废水中的Cu²⁺和Zn²⁺低于GB 21900-2008电镀废水新建企业污染物排放限值要求,而COD没有满足排放要求,所以仅应用高炉水淬渣吸附技术还不足以去除电镀废水中所有有害物质,因此可利用此技术作为辅助工艺,联合其他技术共同去除电镀废水中的重金属离子和有机物,使出水水质达到国家排放标准。