响应面法优化Zn-Mn-Co/HZSM-5催化乙醇脱水制乙烯

采用响应面法研究温度、乙醇浓度、质量空速对锌、锰、钴改性的HZSM-5催化乙醇脱水制备乙烯过程中乙烯收率的影响。结果表明反应温度对乙烯收率影响最大,并且各因素之间存在交互作用。用响应面方法确定乙醇脱水制备乙烯的最佳工艺条件是：温度261.3 ℃,乙醇浓度34.4％,质量空速1.18 h?1,在该条件下乙烯收率达到98.69％。     

Optimization of the Emerson-Trinder enzymatic reaction by response surface methodology

The Emerson-Trinder reaction has been optimized in this work using an initial rate spectrophotometric method and response surface methodology (RSM). In this investigation, the variation range of critical variables along with the fixed parameters were selected based on a preliminary 'one at a time' (OVAT) procedure for the subsequent RSM chemometric analysis as follows: pH (6-10), buffer concentration (50-250 mM), 4-aminoantipyrine (4-AAP) concentration (1-5 mM), temperature (25-45°C). The optimum values of fixed parameters were: 4-fluorophenol (4-FP, 30 mM), horseradish peroxidase (HRP) enzyme activity (0.12 U mL^-1), and the fixed concentration of the H₂O₂ in the chemometric experiments was 11.4 µM. The non-linear nature of the experimental response of the reaction system was explained by a second-order polynomial equation, which revealed the impact of the experimental factors, their interactions and also their optimum values. The results of the reported RSM analysis proved to be quite appropriate for the design and optimization of this reaction, as illustrated by the relatively high value of the determination coefficient (R²=96.7%) for the fitting of quadratic model, along with the satisfactory results generated by the analysis of variance (ANOVA). All the evaluated analytical characteristics of this method: typical reaction progress curves, resulting linear calibration curve, within-day precisions at low and at high levels, and the upper and lower detection limits were, also, reported. In addition, to check the quality of the optimization and validity of the model, the assay of H₂O₂, in pooled serum matrix and in cosmetic samples, was performed.     

Application of solvent engineering to optimize lipase-catalyzed 1,3-diglyacylcerols by mixture response surface methodology

1,3-Diacylglycerol has been introduced in Japan as a cooking oil under the trade name of Econa to reduce body fat accumulation. Solvent engineering was applied to determine the optimum solvent mixtures for the lipase-catalyzed synthesis of 1,3-DAG by mixture response surface methodology. n-Hexane was required to maintain the lipase activity and the product selectivity could be adjusted by changing the hydrophobicity of reaction medium. The optimum yield (40%) of 1,3-DAG synthesis was obtained with n-hexane/octane (1:1, v/v).     

酶法制备1-磷酸葡萄糖合成条件的响应曲面法优化

以葡萄糖为原料,三聚磷酸钠为磷酰化试剂,马铃薯磷酸化酶为催化剂,制备1-磷酸葡萄糖.利用Box-Behnken实验设计原理,采用三因素三水平的响应面分析法,以产物含量为响应值考察温度、物料比(葡萄糖/三聚磷酸钠)、时间3个因素影响.采用氢核磁共振波谱仪对产品进行了分析.结果表明,马铃薯磷酸化酶制备葡萄糖磷酸酯的最佳工艺条件为:温度35℃,葡萄糖与三聚磷酸钠物料比为1.35∶1(mol/mol),时间19h.     

Study on response surface methodology (RSM) of lipase-catalyzed synthesis of palm-based wax ester

The synthesis of wax ester using refined, bleached and deodorized (RBD) palm oil and oleyl alcohol catalyzed by lipozyme IM was carried out. Response surface methodology (RSM) based on a five-level, four-variable central composite rotatable design (CCRD) was used to evaluate the interactive effects of synthesis, of reaction time (2.5–10 h), temperature (30–70 °C), amount of enzyme (0.1–0.2 g) and substrate molar ratio (palm oil to oleyl alcohol, 1:1–1:5) on the percentage yield of wax esters. The optimum conditions derived via RSM were: reaction time 7.38 h, temperature 53.9 °C, amount of enzyme 0.149 g, and substrate molar ratio 1:3.41. The actual experimental yield was 84.6% under optimum condition, which compared well to the maximum predicted value of 85.4%.     

酶法合成2-氧-α-D-葡萄糖基-L-抗坏血酸(AA-2G)条件的研究

采用单因素优化法对环糊精葡萄糖苷转移酶(CGTase)合成糖基抗坏血酸(AA-2G)条件进行优化,AA-2G的产量为2.76 g/L,比未优化前0.46g/L提高了500%。再采用响应面法对AA-2G合成条件进行优化。由Plackett-Burman法筛选出三个主要因素为:pH、V_C和麦芽糊精浓度;由最陡爬坡实验得出最佳响应面区域;最后由Box-Behnken实验,得到最优条件为:pH 5.51,V_C36.16g/L,麦芽糊精28.54 g/L,转化时间24 h,温度37℃。在此条件下,AA-2G的理论产量为3.15 g/L,通过验证实验,得出AA-2G的产量为3.13 g/L,与预测的理论值接近,比单因素优化的结果(2.76g/L)提高了14%。     

响应面法优化Burkholderiasp．SYBCLIP—Y发酵产低温脂肪酶条件的研究

用响应面法对Burkholderiasp．SYBCLIP—Y液体发酵产低温脂肪酶的发酵条件进行了快速优化。首先利用Plackett—Burman设计对影响其产酶相关因素进行评估并筛选出具有显著效应的三个因素：牛肉膏,橄榄油,TritonX-100;用最陡爬坡路径逼近最大产酶区域后,利用响应面中心组合设计对显著因素进行优化,确定出牛肉膏,橄榄油,TritonX-100的最佳浓度分别为：牛肉膏31．8g／L、橄榄油21mL／L、TritonX-10036．55mL／L,优化后脂肪酶的酶活达到61．52U／mL,是优化前的2．62倍。     

响应面法优化酶法转化合成维生素C糖苷（AA-2G）条件的研究

采用Design—Expert软件的Central Composite Design（CCD）响应面设计对环糊精葡萄糖苷转移酶转化合成糖基抗坏血酸（AA-2G）的五个主要因素（转化时间、转化温度、pH、Vc浓度、β-环糊精浓度）进行了研究。采用降维分析方法对pH与转化时间、转化温度、Vc浓度、β-环糊精浓度以及反应温度与反应时间的交互作用对酶法转化合成AA-2G的影响进行了分析。建立了影响因素与响应值之间的回归方程,根据回归方程优化得到最佳转化条件为：转化时间25h,温度36．5℃,pH5．4,Vc72dL,β-环糊精55g／L。在此条件下,AA-2G的理论产量为10．06g／L,在验证实验中AA-2G的产量为9．76g／L,与预测的理论产量接近,比优化前提高了33％。     

响应面法优化福鸽霉素发酵培养基

采用Plackett-Burman设计法,对影响纤维堆囊菌So ceMWXAB-125产生福鸽霉素的9个因素进行了筛选。结果表明,影响该菌产生福鸽霉素的主要营养因素为马铃薯淀粉、CaCl2和脱脂奶粉。在此基础上,采用响应面法对其中3个显著因子的最佳水平范围进行研究,利用Design-Expert软件进行二次回归分析得知,马铃薯淀粉、CaCl2和脱脂奶粉的质量浓度分别为8.05、2.72和10.00 g/L时,福鸽霉素的产量从67 mg/L提高到119.98 mg/L。     

响应面优化产琥珀酸放线杆菌生产丁二酸

丁二酸是一种重要的C4化合物平台,可以合成一系列重要化合物。文中对产琥珀酸放线杆菌Actinobacillus succinogenes GXAS137发酵生产丁二酸培养基成分进行优化。通过单因素和Plackett-Burman试验设计筛选出影响丁二酸发酵的重要参数,采用最陡爬坡实验逼近最大丁二酸生产区域后,利用Box-Behnken设计确定重要参数的最佳水平。筛选结果表明,影响丁二酸产量的重要参数是葡萄糖、酵母提取物和碱式碳酸镁浓度。最佳条件为(g/L)：葡萄糖70.00,酵母提取物9.20,碱式碳酸镁58.10。优化后丁二酸产量达到47.64 g/L。与初始条件 (36.89 g/L) 相比,丁二酸浓度提高了30 %。在最佳工艺条件下得到的试验结果与模型预测值很吻合,说明建立的模型是有效的。     

Optimization of flocculation conditions for kaolin suspension using the composite flocculant of MBFGA1 and PAC by response surface methodology

The response surface methodology (RSM) was employed to study the treatment of kaolin suspension by the composite flocculant of MBFGA1 and PAC. And the two quadratic models of the five factors were established with the flocculating rate and floc size as the target responses. The optimal flocculating conditions are MBFGA1 99.75 mg/L, PAC 121 mg/L, pH 7.3, CaCl₂ 27 mg/L and the top speed of stir 163 rpm, respectively. That was obtained from the compromised results of two desirable responses, flocculating rate as 100% and floc size as 0.7 mm which were deduced from the frequency of responses. By means of Zeta potential measurement and experiment of flocculating process, it could be concluded that PAC has more capability on changing the potential of colloid and MBFGA1 is good at absorption and bridge effect. The composite of two kinds of predominance makes a significant sense on enhancing flocculating rate, reducing flocculent costs and decreasing secondary pollution.     

响应面法对红法夫酵母合成虾青素主要影响因素的优化

在单因素试验确定了红法夫酵母生物合成虾青素培养基组份的基础上,用响应面法对其浓度进行优化。首先用分式析因设计评价了培养基的各组份对虾青素产量的影响,并找出主要影响因子为蔗糖和酵母粉,二者分别达到了极显著和显著水平。用最陡爬坡路径逼近最大响应区域后,运用旋转中心复合设计及响应面分析,确定了主要影响因子的最佳浓度。其中,蔗糖的最佳浓度为49.8g/L,酵母粉的浓度为9.6g/L。菌株在优化培养基中的虾青素产量为9861μg/L,比优化前增加了近1倍。     

响应面法优化产酰胺酶发酵培养基

采用响应面分析方法,对阿萨希丝孢酵母（Trichosporon asahii）ZZB-1产酰胺酶的发酵培养基进行了优化。运用单N子试验筛选出麦芽糖和酵母浸膏为最适碳源、氮源,金属离子Ca^2＋、Mn^2＋可提高发酵酰胺酶产量;通过最陡爬坡实验逼近以上4个因子的最大响应区域后,采用Box—Behnken响应面分析法,确定产酰胺酶最佳发酵培养基为麦芽糖18．84g／L、酵母浸膏9．55g／L、NaC15g／L、KH2PO41g／L、MgSO4·7H2O0．2g／L、FeS040．001g／L、CaC0370．84μmol／L、MnS0465．39肚mo[／L（1％丙烯酸诱导）,NH4·H2O调节pH至7．0。培养基优化后酰胺酶产量由初始2554U／L提高到4156U／L,为原始发酵培养基配方酶活产量的1．63倍。     

Optimization of the multienzyme system for sucrose biosensor by response surface methodology

An immobilized multienzyme- and cathodic amperometry-based biosensor for sucrose was constructed for the analysis of food and fermentation samples. The multienzyme system, comprising invertase, mutarotase and glucose oxidase (GOD), was immobilized by using glutaraldehyde as cross-linking agent. Operating parameters of the biosensor for the estimation of sucrose in the range 1–10% were standardized. Response surface methodology (RSM) based on three-factor, three-variable design was used to evaluate the effect of important variables (concentration of enzymes, (varied in the range invertase (10–50 IU), mutarotase (5–105 IU) and GOD (1–9 IU)) on the response of biosensor. In the range of parameters studied, response time decreased with decrease in the invertase and with increase in mutarotase and GOD. Mutarotase concentration above 75 IU was found to result in an increased response time due to inhibition of mutarotase by its product -D-glucose. The optimal conditions achieved for the analysis of sucrose were: invertase 10 IU, mutarotase 40 IU, and GOD 9 IU. With these conditions, the predicted and actual experimental response time values were 2.26 and 2.35 min respectively, showing good agreement.     

基于响应面设计脂肪酶Novo435催化合成甘油二酯的工艺优化

以甘油、油酸为原料,优化在无溶剂体系中以固定化脂肪酶Novo435催化合成甘油二酯（diglyceride,DAG）的工艺。系统考察底物摩尔比（油酸／甘油）、反应温度、时间和加酶量等因素对油酸转化率和甘油二酯含量影响的基础上,利用响应面试验设计优化各主效因子,并经回归分析获得最优的工艺条件。所得最优条件：油酸与甘油底物摩尔比2．27、反应温度48．14℃、反应时间6．3h、加酶量1．68％。在此条件下,实验测得油酸转化率为45．42％,甘油二酯质量分数为70．01％,与响应面模型预测值吻合。     

Optimization of lipase-catalyzed synthesis of acetylated EGCG by response surface methodology

(−)-Epigallocatechin-3-O-gallate (EGCG) acetylated derivatives, which can be widely used as a natural antioxidant in both lipid containing food and cosmetic applications, were prepared by lipase catalyzed acylation of EGCG with vinyl acetate. Response surface methodology (RSM) and 5-level-4-factor central composite rotatable design (CCRD) were employed to evaluate the effects of synthesis parameters, such as reaction time (6–10 h), temperature (30–50 °C), enzyme amount (1.5–2.5% (w/w) of substrate), and substrate molar ratio of EGCG to vinyl acetate (0.5–1.5) on conversion of EGCG. By using multiple regression analysis, the experimental data were fitted to a second order polynomial model. The most suitable combination of variables was 40 °C, 2.12%, 10 h and 1.13 for the reaction temperature, the enzyme amount, the reaction time, and EGCG/vinyl acetate mole ratio, respectively. At these optimal conditions, the conversion yield reached 87.37%. The presence of mono-, di- and tri-acetylated derivatives in acetylated EGCG was confirmed by LC–MS-MS and identified as 5″-O-acetyl-EGCG, 3″, 5″-2-O-acetyl-EGCG and 5′, 3″, 5″-3-O-acetyl-EGCG by NMR.     

响应面法优化以豆饼粉为基质发酵猪苓菌

为了提高豆饼粉的附加值,以豆饼粉为液体基质发酵猪苓菌。首先用Plackett-Burman方法筛选出影响菌体产量的主要因素,继而采用中心组合设计及响应面分析确定主要影响因子的最佳浓度。通过实验发现,当豆饼粉质量分数为3.7%,蛋白胨质量分数为0.6%,MgSO4质量分数为0.27%时,菌体产量达到最大值47.44 g/L。     

Modeling and optimization of lipase-catalyzed esterification of policosanols with conjugated linoleic acid by response surface methodology

Abstract

The aim of this study was to model the lipase-catalyzed esterification of policosanols with conjugated linoleic acid (CLA) in a solvent-free system to produce wax esters which had a lower melting point than that of their corresponding policosanol forms and to optimize the reaction conditions by response surface methodology (RSM). Novozym 435 was selected as a suitable biocatalyst for the reaction. The molar ratio of substrates (policosanols to CLA) was 1:2. A well-fitting quadratic polynomial regression model for the degree of esterification (DE) of policosanols with CLA was established with regard to temperature (35–65°C), enzyme loading (1–5% of weight of total substrates), and reaction time (10–50 min). Optimal reaction conditions were 61.3°C for temperature, 3.7% for enzyme loading, and 34.1 min for reaction time, and the DE was ? 95 mol% under these conditions. The policosanols and wax esters synthesized under optimal conditions had melting points of 79°C and 57°C, respectively.     

Optimization of medium constituents and fermentation conditions for the production of ethanol from palmyra jaggery using response surface methodology

The quantitative effects of sugar concentration, nitrogen concentration, EDTA, temperature, pH and time of fermentation on ethanol production were optimized using a Box-Wilson central composite design (CCD) experiment. It was found that palmyra jaggery (sugar syrup from the palmyra palm) is a suitable substrate for the production of high concentrations of ethanol using Saccharomyces cerevisiae NCIM 3090 by submerged fermentation. A maximum ethanol concentration of 129.4 g/l was obtained after optimizing media components and conditions of fermentation. The optimum values were a temperature of 26.2 °C, pH of 8.4, time of fermentation of 4.2 days with 398.5 g of substrate/l, 3.1 g of urea/l and 0.51 g of EDTA/l. Thus by using the CCD, it is possible to determine the accurate values of the fermentation parameters where maximum production of ethanol occurs.     

响应面法优化荷叶离褶伞菌丝体产漆酶条件

为了对荷叶离褶伞产漆酶条件进行优化,在单因素实验基础上,通过最陡爬坡实验(PB)对培养基8因素进行筛选,获得影响产漆酶的3个显著性因素:葡萄糖,pH和KH₂PO₄;通过中心组合(CCD)设计及响应面分析确定了最优发酵条件:葡萄糖20.09g/L,酪蛋白1.5g/L,酵母提取物1.5g/L,MgSO₄ 3g/L,CuSO₄ 3.75mg/L,KH₂PO₄ 3.97g/L,pH 4.98,VB₁ 0.1g/L,愈创木酚12mg/L,该条件下,漆酶酶活为829.83U/mL,较未优化对照提高46.6%.