Biosorption of Cr(VI) by Ceratocystis paradoxa MSR2 Using Isotherm Modelling,Kinetic Study and Optimization of Batch Parameters Using Response Surface Methodology

This study is focused on the possible use of Ceratocystis paradoxa MSR2 native biomass for Cr(VI) biosorption. The influence of experimental parameters such as initial pH, temperature, biomass dosage, initial Cr(VI) concentration and contact time were optimized using batch systems as well as response surface methodology (RSM). Maximum Cr(VI) removal of 68.72% was achieved, at an optimal condition of biomass dosage 2g L⁻¹, initial Cr(VI) concentration of 62.5 mg L⁻¹ and contact time of 60 min. The closeness of the experimental and the predicted values exhibit the success of RSM. The biosorption mechanism of MSR2 biosorbent was well described by Langmuir isotherm and a pseudo second order kinetic model, with a high regression coefficient. The thermodynamic study also revealed the spontaneity and exothermic nature of the process. The surface characterization using FT-IR analysis revealed the involvement of amine, carbonyl and carboxyl groups in the biosorption process. Additionally, desorption efficiency of 92% was found with 0.1 M HNO₃. The Cr(VI) removal efficiency, increased with increase in metal ion concentration, biomass concentration, temperature but with a decrease in pH. The size of the MSR2 biosorbent material was found to be 80 μm using particle size analyzer. Atomic force microscopy (AFM) visualizes the distribution of Cr(VI) on the biosorbent binding sites with alterations in the MSR2 surface structure. The SEM-EDAX analysis was also used to evaluate the binding characteristics of MSR2 strain with Cr(VI) metals. The mechanism of Cr(VI) removal of MSR2 biomass has also been proposed.     

响应面法优化灵芝菌丝体胞内灵芝酸的提取

利用单因子试验和响应面法优化了影响灵芝菌丝体灵芝酸的提取过程。基于3因素3水平的中心组合设计,得到了描述胞内灵芝酸提取得率与操作参数之间的二次响应面模型。在乙醇浓度为93.6%(v/v)、提取温度79.1℃、提取液固比42.2∶1、提取次数2次、每次提取时间2 h的条件下,最大灵芝酸理论提取得率为28.36 mg胞内灵芝酸每克干菌丝。模型优化条件下的实际灵芝酸提取得率(28.72 mg/g干菌丝)与理论灵芝酸提取得率(28.36 mg/g干菌丝)相符。     

Optimization of Influencing Parameters on Phenanthrene Removal Efficiency in Soil Washing Process by Using Response Surface Methodology

Response surface methodology (RSM) under Box–Behnken design (BBD) was applied to evaluate the effect of the influencing parameters including surfactant concentration, liquid/soil ratio, Humic Acid concentration, and washing time on phenanthrene removal efficiency in soil washing process by using the nonionic surfactant Tween 80 and find an optimal operational conditions to achieve the highest removal efficiency. A polynomial quadratic model was used to correlate phenanthrene removal efficiency and four independent variables (R² = 0.9719). Based on the obtained results the most influential parameter on phenanthrene removal efficiency was surfactant concentration with an impact value of 69.519%. Liquid/soil ratio was also another factor that significantly influenced on removal efficiency with an impact value of 25.014%. The interaction between surfactant concentration and liquid/soil ratio was also shown to have a positive significant effect on removal efficiency (p_value = 0.0027). However, the other independent variables Humic Acid concentration and time were not significant in the ranges selected in this study. Based on the optimization results maximum removal efficiency of 70.692 ± 3.647% was achieved under the conditions of surfactant concentration 5000 mg L^?1, liquid/soil ratio 30 v/w, HA concentration 9.88 mg L^?1, and washing time 2 h, which was in good agreement with predicted value (66.643%).     

Investigation of Cr(VI) adsorption onto chemically treated Helianthus annuus: Optimization using Response Surface Methodology

In the present study, chemically treated Helianthus annuus flowers (SHC) were used to optimize the removal efficiency for Cr(VI) by applying Response Surface Methodological approach. The surface structure of SHC was analyzed by Scanning Electron Microscopy (SEM) coupled with Energy Dispersive X-ray Analysis (EDX). Batch mode experiments were also carried out to assess the adsorption equilibrium in aqueous solution. The adsorption capacity (q_e) was found to be 7.2 mg/g. The effect of three parameters, that is pH of the solution (2.0-7.0), initial concentration (10-70 mg/L) and adsorbent dose (0.05-0.5 g/100 mL) was studied for the removal of Cr(VI) by SHC. Box-Behnken model was used as an experimental design. The optimum pH, adsorbent dose and initial Cr(VI) concentration were found to be 2.0, 5.0 g/L and 40 mg/L, respectively. Under these conditions, removal efficiency of Cr(VI) was found to be 90.8%.     

Environmental and Kinetic Parameters for Cr(VI) Bioreduction by a Bacterial Monoculture Purified from Cr(VI)-Resistant Consortium

Hexavalent chromium, Cr(VI), is toxic to living systems. Widespread contamination of water and soil by Cr(VI) present a serious public health problem. Chromium-resistant bacteria can reduce and detoxify Cr(VI). Twelve bacteria resistant to high concentrations of Cr(VI) were isolated from soil enrichment cultures. Environmental parameters and kinetic parameters of Cr(VI) bioreduction by one monoculture isolate, identified by 16S rRNA gene sequence as Bacillus sp. PB2, were studied. The optimal temperature for growth and Cr(VI) reduction was 35 degrees C. The isolate grew luxuriantly and substantially reduced Cr(VI) at initial pH 7.5 to 9. Maximal Cr(VI) bioreduction occurred at initial pH 8.0. Substantial Cr(VI) bioreduction was observed in salt media, but removal efficiency was inversely related to salt concentration (1-9%). Michaelis-Menten hyperbolic equation and the Lineweaver-Burk double reciprocal plot were comparatively employed to determine the k (m) and V (max) of Cr(VI) bioreduction. A k (m) of 82.5 microg mL(-1) and V (max) of 7.78 microg mL(-1) h(-1) were calculated by nonlinear regression analysis of the hyperbola curve. Linear regression analysis of the double reciprocal plot revealed k (m) and V (max) of 80.9 microg mL(-1) and 10.6 microg mL(-1) h(-1), respectively. Time course studies displayed about 90% reduction of Cr(VI) at an initial concentration of 8,000 microg L(-1) in 8 h, with an estimated t (1/2) of 4 h. Data from time course analysis of the rate of Cr(VI) bioreduction fitted zero-order model, and the kinetic constant k was calculated to be 840 microg L(-1) h(-1). The monoculture isolate, Bacillus sp. PB2, strongly reduces Cr(VI) and could be used for bioremediation of Cr(VI)-contaminated aquatic and terrestrial environments.     

利用响应面法优化红谷霉素发酵培养基*

在摇瓶条件下,对链霉菌702发酵生产过程中的主要培养基组成对产红谷霉素影响进行的研究。试验采用响应面法优化摇瓶发酵培养基,利用全因子实验设计筛选出对链霉菌702产红谷霉素重要影响因子黄豆饼粉和工业蛋白胨,应用最陡爬坡实验法接近重要因子的最优水平,然后应用中心复合设计确定重要因子的最优水平。优化后的培养基组成为：玉米淀粉20g,玉米粉20g,葡萄糖20g,磷酸二氢钾0．3g,蛋白胨9g,黄豆饼粉23g,硝酸钾2．5g,硫酸铵2．5g,豆油5mL,氯化钠3g,碳酸钙6g,定容至1L。实验结果表明,采用优化后的培养基,其发酵液红谷霉素效价达到1,500μg／mL,比优化前提高了3.08倍。     

响应面法优化普通小球藻混合营养培养基组成生产生物质

利用响应面法优化了混合营养培养普通小球藻生产生物质的培养基组成.首先采用Plackett-Burman设计对11个相关营养因素的效应进行了评价,并筛选出影响小球藻细胞生长的3个主要因素为KNO3、葡萄糖和NaC1;然后结合Box-Behnken设计建立了以小球藻浓度为响应值的二次回归方程模型,获得优化的培养基组成为KNO31.64g/L、葡萄糖45g/L、NaC1 1.57g/L;模型预测的最大浓度为5.28g/L,验证值为5.68g/L;验证结果表明,所建立模型预测精度较好,可用于优化小球藻的混养培养基组成.优化条件下混养小球藻细胞的蛋白质和色素含量较优化前降低,而可溶性糖和油脂含量提高,脂肪酸以棕榈酸和油酸为主;细胞组分分析结果显示,混养培养所得小球藻生物质具有作为生产微藻生物能源原料的潜力.     

响应面分析法优化(R)-扁桃酸发酵培养基

采用响应面分析法对Bacillussp.HB20菌株合成(R)-扁桃酸的培养基成分进行优化。首先利用Plackett-Burman试验设计筛选出影响(R)-扁桃酸产率的三个主要因素:麦芽糖、蛋白胨和牛肉膏。在此基础上用最陡爬坡路径逼近最大响应区域,再利用Box-Behnken试验设计及响应面分析法进行回归分析。结果表明,麦芽糖、蛋白胨和牛肉膏浓度与(R)-扁桃酸产率存在显著的相关性,通过求解回归方程得到最佳质量浓度:蛋白胨11.507g/L,牛肉膏6.708g/L,麦芽糖10.907g/L,(R)-扁桃酸产率理论最大值达到66.87%。经模型验证,预测值与验证试验平均值接近,在优化条件下(R)-扁桃酸产率提高了25.87%。     

Optimization of PEGylation Conditions for BSA Nanoparticles Using Response Surface Methodology

Chemical coupling of polyethylene glycol (PEG) to proteins or particles (PEGylation), prolongs their circulation half-life by greater than 50-fold, reduces their immunogenicity, and also promotes their accumulation in tumors due to enhanced permeability and retention effect. Herein, phase separation method was used to prepare bovine serum albumin (BSA) nanoparticles. PEGylation of BSA nanoparticles was performed by SPA activated mPEG through their free amino groups. Effect of process variables on PEGylation efficiency of BSA nanoparticles was investigated and optimized through response surface methodology with the amount of free amino groups as response. Optimum conditions was found to be 32.5 g/l of PEG concentration, PEG-nanoparticle incubation time of 10 min, incubation temperature of 27°C, and pH of 7 for 5 mg of BSA nanoparticles in 1 mL phosphate buffer. Analysis of data showed that PEG concentration had the most noticeable effect on the amount of PEGylated amino groups, but pH had the least. Mean diameter and zeta potential of PEGylated nanoparticles under these conditions were 217 nm and −14 mV, respectively. In conclusion, PEGylated nanoparticles demonstrated reduction of the negative surface charge compared to the non modified particles with the zeta potential of −31.7 mV. Drug release from PEGylated nanoparticles was almost slower than non-PEGylated ones, probably due to existence of a PEG layer around PEGylated particles which makes an extra resistance in opposition to drug diffusion.     

响应面分析法优化超声提取蓖麻碱工艺

以蓖麻叶为原料,对蓖麻碱的超声提取工艺优化进行研究,在单因素试验的基础上,选择超声时间、超声功率、料液比为自变量,以蓖麻碱提取率为影响值,采用响应面试验设计方法,研究各自变量及其交互作用对蓖麻碱提取率的影响。利用Design Expert8软件得到回归方程得模型并进行响应面分析,确定超声提取蓖麻碱的最佳工艺条件为料水比为1∶25 g/mL,超声时间为103.03 min,超声功率为621.05 W,此条件下蓖麻碱的提取率为2.63‰。     

Optimization of Phosphatidylinositol-specific Phospholipase C Production Using Response Surface Methodology

Summary Response surface methodology was employed in optimizing the nutrient levels needed towards the optimal production of phosphatidylinositol-specific phospholipase C enzyme by Bacillus thuringiensis serovar. kurstaki. A 2³ factorial central composite experimental design was used. The multiple regression equation, relating the enzyme activity to the nutrient medium, was used to find the optimum values of glucose, peptone and dipotassium hydrogen phosphate. The optimum values of these variables for maximal enzyme production were found to be: glucose, 6.5 g l⁻¹; peptone, 5.38 g l⁻¹ and dipotassium hydrogen phosphate, 6.36 g l⁻¹ with the predicted enzyme activity of 0.96 U ml⁻¹.     

Estimation of Kinetic Parameters for Bioremediation of Cr(VI) from Wastewater Using Pseudomonas taiwanensis,an Isolated Strain from Enriched Mixed Culture

An aerobic mixed culture collected in the form of activated sludge was enriched for Cr(VI) reduction. An indigenous microorganism was isolated from the enriched aerobic mixed culture and identified as Pseudomonas taiwanensis. Bioremediation studies were carried out for treating Cr(VI)-contaminated wastewater using the indigenous microorganism. The kinetic studies were carried out for initial Cr(VI) concentrations ranging from 20 to 200 mg L^?1. The maximum consumption of Cr(VI) obtained was 108.3 mg L^?1 for an initial Cr(VI) concentration of 150 mg L^?1 at a solution pH of 7.0. The effect of nutrient dosage and pH were studied to get their optimum values. The same isolated bacterial strain was also used to treat Cr(VI)-contaminated industrial wastewater collected from a local plating industry. Various growth kinetic models, such as Monod, Powell, Haldane, Luong, and Edward models, were fitted with the obtained experimental data. The obtained results for different growth kinetic models indicate that the growth kinetics of Pseudomonas taiwanensis for bioremediation of Cr(VI) can be better understood by the Luong model (R² = .913). The rate kinetic analysis was performed using zero-order and three-half-order kinetic models. The three-half-order kinetic model was found to be suitable for the present bioremediation study.     

响应面法优化超声辅助提取紫色小白菜花青苷的工艺研究

为探讨从紫色小白菜(Brassica campestris L.ssp.chinensis(L.)Makino var.communis Tsen et Lee)叶片中提取花青苷的最佳工艺条件,在超声功率为420 W、40%乙醇和两次超声提取条件下,采用Box-Behnken的中心组合试验设计原理,设计4因素3水平试验,研究了pH、料液比、超声温度、超声时间对花青苷得率的影响。结果表明,紫色小白菜叶片花青苷提取的优化工艺参数为料液比1∶16(pH 2.76),在超声功率为420 W、温度为58℃下超声12 min,花青苷的提取得率可达4.11 mg g–1 DW。     

响应面法优化重组工程菌的发酵工艺条件

目的：对基因改造运动发酵单胞菌的发酵工艺条件进行优化,提高重组菌发酵乙醇产量。方法：使用分子克隆实验操作技术构建重组运动发酵单胞菌,以单因素实验为基础,利用Box-Behnken中心组合实验和响应面分析法,确定了影响重组菌高产乙醇的三个重要因素。结果：成功构建含有YfdZ、MetB基因和Hsp基因的重组菌Zymomonas mobilis HYM,发酵主要影响因素的最佳条件分别为温度28℃,葡萄糖浓度24%（W/V）,pH7.4。在此优化条件下,Zymomonas mobilis HYM的乙醇产量可高达105.0735g/l,比原始菌株乙醇产量提高16.4%。结论：用中心组合设计和响应面分析法优化重组运动发酵单胞菌的发酵工艺条件,显著提高乙醇产量。     

利用响应面法优化L-组氨酸摇瓶发酵培养基

通过单因素实验对L-组氨酸产生菌LGS4的发酵培养基成分进行筛选,确定了3个影响较大的重要因素,即酵母膏、尿素、硫酸镁。在此基础上,采用二次响应面分析法进行回归分析,得到各因素的最佳水平值。经5批培养验证,预测值与验证试验平均值接近。优化后培养基组成为(g.L-1):蔗糖150,硫酸铵50,酵母膏10,尿素1.2,MgSO42.2,KH2PO41.5,K2HPO40.5,Na2HPO40.5。优化后的发酵培养基使LGS4菌株的L-组氨酸产量提高了15.25%。     

响应面法优化重组hCu,Zn-SOD改构体发酵培养基

目的:优化已构建的重组hCu,Zn-SOD改构体基因工程菌的发酵培养基,提高重组hCu,Zn-SOD改构体活性蛋白产量.方法:单因素实验筛选发酵培养基的碳源和氮源,Plackett Burman设计筛选影响hCu,Zn-SOD活性的重要影响因子,最陡爬坡实验逼近重要影响因子的hCu,Zn-SOD活性的最大响应区域,Box-Behnken及响应分析法进行回归分析.结果:重组hCu,Zn-SOD改构体发酵培养基重要影响因子的最优取值为:酵母提取物7.4646g.L,NaNO3 0.7129g/L,Na2HPO4·12H2O30.4876g/L,KH2PO4 4.1830g/L,优化后的hCu,Zn-SOD活性是1470700U/L,较初始培养基提高了1.04倍.结论:响应面法优化重组hCu,Zn-SOD的发酵培养基提高了hCu,Zn-SOD的活性和产量,为重组hCu,Zn-SOD的工业化生产提供依据.     

丛梗孢酵母发酵产赤藓糖醇的响应面优化

为了提高丛梗孢酵母发酵产赤藓糖醇的产量,在前期单因素实验结果的基础上,利用Plackett-Burman实验设计对影响其产赤藓糖醇的发酵条件进行评估并筛选出了影响显著的3个因素:葡萄糖、初始pH和温度.采用响应面法进行实验方案设计,利用SAS软件对其结果进行二次回归分析,确定了优化后的发酵条件为:葡萄糖260g/L、酵...     

响应面法优化脯氨酸羟化酶转化反应工艺条件

通过优化脯氨酸羟化酶表达条件和转化反应条件,提高其转化反应效率。采用单因素法筛选脯氨酸羟化酶的最佳诱导温度、诱导剂浓度和转化反应条件,并采用响应面法预测影响转化反应各因素的最佳条件。结果显示,经过筛选和验证,蛋白表达最适诱导温度为28℃,IPTG浓度为0.2 mmol/L;转化反应最佳条件为:120 mmol/L 2-(N-吗啡啉)乙磺酸(pH 6.6)、1.5% Nonidet P-40、200 mmol/L L-脯氨酸、200 mmol/L α-酮戊二酸,6 mmol/L L-抗坏血酸、6.0 mmol/L 硫酸亚铁,最适反应温度为27℃,振荡速率为152 r/min。在最佳条件下,转化反应进行48 h后产物反式-4-羟基-L-脯氨酸的转化率可达100%,为合成反式-4-羟基-L-脯氨酸奠定了坚实的实验基础。     

响应面优化-超声提取黄姜中总黄酮工艺研究

目的:利用响应面法对黄姜总黄酮的提取工艺进行优化.方法:在单因素的基础上以超声功率、超声时间、料液比、乙醇浓度为响应因素,黄姜总黄酮的提取率为响应值,根据中心组合实验原理,采用四因素三水平的响应面分析法.结果:确定提取最佳工艺参数为超声时间29.53 min、超声功率为400.76w、料液比为1:42.19、乙醇浓度为79.60％,在此条件下总黄酮提取率的预测值为11.15 (mg/g).结论:考虑到实际操作的问题,将提取最佳工艺参数修正为超声时间30 min、超声功率400w、料液比1:40、乙醇浓度80％,进行3次平行试验,结果总黄酮提取率为11.09 mg/g,绝对误差为0.057％,说明实验结果与模型吻合很好.     

Optimization of the Endotoxin Removal Performance of Solid-Phase Conjugated S3E3 Antimicrobial Peptide Using Response Surface Methodology

S3E3 is a new variant of S3 antimicrobial peptide (AMP) derived from factor C of horseshoe hemolymph and features a high binding affinity for endotoxin. In this research, site-specific conjugated S3E3 AMP onto Sepharose 6% solid phase support (S3E3-S-Sepharose) was applied for endotoxin removal from protein solutions. The bovine serum albumin (BSA) was chosen as a protein model due to its acidic-sticky nature interfering with the endotoxin removal process. The batch process parameters including, endotoxin concentration, pH, and ionic strength of the sample were optimized by response surface methodology to reach maximum endotoxin binding capacity and protein recovery. The predicted optimal conditions for enhanced endotoxin removal performance were as follows: pH 4.5, 25 mM NaCl, and 68,500 EU/ml endotoxin leading to a maximum endotoxin binding capacity of 3.114?×?10⁺⁶ EU/ml of resin and a 95.89% protein recovery. S3E3-S-Sepharose could be applied as an efficient endotoxin removal affinity chromatography matrix at downstream processes of recombinant therapeutics due to its high capacity and protein recovery.