基于SASV8.1的黄嘌呤氧化酶产酶培养基的优化

培养基优化属多变量目标函数优化,先通过Plackett-Burman法筛选出黄嘌呤、(NH4)2SO4和CaCl2为重要因素,然后采用Box-Behnken设计重要因素水平,同时应用SASV8.1软件做多元非线性回归,建立黄嘌呤氧化酶产酶培养基的优化模型.用模型预测培养基的最优组成.将预测值与验证值相比较,误差为2.6%,证明采用响应面法寻求最佳培养基组成是可行的;并且优化后黄嘌呤氧化酶产酶水平提高了5倍.     

响应面法优化农产品中抗性淀粉的体外检测

目的 采用响应面法优化农产品中抗性淀粉(Resistant Starch, RS)的体外检测方法。方法 选择谷类、薯类、豆类3类抗性淀粉主要来源的农产品，设计单因素试验和Box-Behnken试验。单因素试验考察了水浴时间、淀粉葡萄糖苷酶（AMYLOGLUCOSIDASE, AMG）作用温度、AMG作用时间、AMG添加量和离心力与离心时间5个条件，并选择AMG作用温度、AMG作用时间、AMG添加量来设计Box-Behnken试验。结果 根据单因素试验，确定了水浴时间为14 h，离心条件选择4500 g离心5 min；根据响应面实验确定对RS含量检测结果影响程度排序为AMG添加量＞AMG作用时间＞AMG作用温度。结合单因素响应面试验，确定最佳检测方法为水浴14 h，4500 g离心5 min，AMG作用温度49℃、AMG添加量0.2 mL、AMG作用时间38 min。结论 优化后的方法重复性良好，适用于玉米、马铃薯和红豆3类样品，且有望适用于其他主要农产品。     

Studies on long-term storage stability of biodiesel (B100) and its blend (B20) using Box-Behnken response surface method

The gradual depletion of fossil fuels has greatly enhanced the necessity to look for alternative fuels for automobile engines. In response to this, biodiesel is being considered as a promising and potential alternative substitute to conventional petroleum diesel. However, long-term storage stability of biodiesel is poorer compared to conventional petroleum diesel. The aim of the project work is to study the long-term storage stability of biodiesel (B100) and its blend (B20) prepared from used frying oil in different conditions of storage. In this work, the effect of antioxidants and temperature on long storage stability of biodiesel obtained from with respect to storage period is analysed using response surface methodology (RSM). The long storage of biodiesel obtained from used frying oils were optimised by varying parameters such as antioxidant concentration, storage period by Box-Behnken RSM. The properties such as the acid value and the viscosity of biodiesel were initially measured. The results of the investigation showed that the addition of sufficient concentration of antioxidant (pyrogallol) significantly maintains the acid value and viscosity of biodiesel and helps to store for a longer storage period at the given storage temperature.     

Optimization of parameters for cerium（III） biosorption onto biowaste materials of animal and plant origin using 5-level Box-Behnken design：Equilibrium,kinetic, thermodynamic and regeneration studies

Response surface methodology （RSM） employing 5-level Box-Behnken design was used to optimize the biosorption of cerium（III） onto biowaste materials of animal and plant origin viz. prawn carapace （PC） and corn style （CS）. Various process parameters viz. pH （A：3.0-9.0）, biomass dosage （B：0.05-0.35 g/L）, initial metal concentration （C：50-350 mg/L）, contact time （D：2-6 h） and temperature （E：20-60 ℃ were chosen for optimization. A log transformation was suggested by the Box-Cox plot in the present case. A low p-value of〈0.0001 validated the significance of the model. Maximum Ce（III） uptake of 218.3 mg/g for PC and 180.2 mg/g for CS was noted under optimum conditions. Among the equilibrium isotherms, Freundlich model was found to be the best fitted one suggesting a heterogeneous mode of biosorption on PC whereas Langmuir model showed the best fit suggesting homogeneous mode of cerium biosorption on CS. This was further confirmed by scanning electron microscopy （SEM）. Kinetic studies showed better applicability of pseudo-first order model suggesting physisorption as phenomena underlying the process. Film-diffusion was suggested by the non-linearity of the Boyd plot. Thermodynamic studies showed that the process was endothermic and spontaneous. FTIR analysis confirmed a major involvement of the participation of amide, amines, ketones and primary alcohol groups during Ce（III） biosorption. EDAX analysis confirmed the major participation of carbon group during Ce（III） biosorption. This was the first report on parameter optimization of Ce（III） biosorption onto biowaste materials using 5-level Box-Behnken experimental design which might be helpful for the recovery of Ce（III） from aqueous environment.     

Content and Color Stability of Anthocyanins Isolated from Schisandra chinensis Fruit

In this work, a multivariate study based on Box-Behnken Design was used to evaluate the influence of three major variables affecting the performance of the extraction process of Schisandra chinensis anthocyanins. The optimum parameters were 5.5 h extraction time; 1:19 solid-liquid ratio and 260 r/min stirring rate, respectively. The extraction yield of anthocyanins was 29.06 mg/g under the optimum conditions. Moreover, many factors on the impact of heating, ultrasound, microwave treatment and ultraviolet irradiation on content and color stability of anthocyanins from Schisandra chinensis fruit were investigated. The results show that thermal degradation reaction of anthocyanins complies with the first order reaction kinetics, and the correlation coefficient is greater than 0.9950 at 40–80 °C. Ultrasound and microwave treatment has little effect on the stability of anthocyanins, and the extraction time of ultrasound and microwave should be no more than 60 min and 5 min, respectively. The anthocyanins degradation effect of UVC ultraviolet radiation is greater than UVA and UVB; after 9 h ultraviolet radiation, the anthocyanins content degradation of UVC is 23.9 ± 0.7%, and the ΔE* was changed from 62.81 to 76.52 ± 2.3. Through LC-MS analysis, the major composition of Schisandra chinensis anthocyanins was cyanidin-3-O-xylosylrutinoside.     

Optimization of combined (acid + thermal) pretreatment for fermentative hydrogen production from Laminaria japonica using response surface methodology (RSM)

In the present work, a combined (acid + thermal) pretreatment was applied for the enhanced fermentative H₂ production (FHP) from Laminaria japonica. Various pretreatment conditions including HCl concentrations, heating temperatures, and reaction times were optimized via response surface methodology (RSM) with a Box-Behnken design (BBD). Through regression analysis, it was found that H₂ yield was well fitted by a quadratic polynomial equation (R² = 0.97), and the HCl concentration was the most significant factor influencing FHP. The desirable pretreatment conditions found were HCl concentration of 4.8%, temperature of 93 °C, and reaction time of 23 min, under which H₂ yield reached to 159.6 mL H₂/g dry cell weight (dcw). The main organic acids produced were acetic and butyric acids that related closely with H₂ production. The concentration of hydroxymethylfurfural (HMF), a byproduct formed during the pretreatment process, showed an inverse relationship with H₂ yield, indicating that pretreatment conditions for the H₂ production from L. japonica were successfully optimized, by increasing the hydrolysis rate of the feedstock and also reducing the formation of HMF.     

响应面法优化产酸丙酸杆菌丙酸发酵条件的研究

采用Box-Behnken设计和响应面分析法(Response surface methodology,RSM),以产酸丙酸杆菌发酵甘油产丙酸的3个关键因素(培养温度、pH和接种量)为自变量,以丙酸产量为响应值,对上述因素的最佳水平范围进行了探讨与优化。实验结果表明,培养温度和pH对丙酸产量有显著性影响,并据此建立了相关的数学模型。得到的工艺参数的优选结果是:培养温度为29.75℃、pH为6.61、接种量为6.15%(v/v),丙酸产量最大预测值为17.96g/L。经过优化,丙酸产量提高了27.9%,实验值与预测值基本相符。     

响应面法优化刺参(Apostichopus japonicus)中金刚烷胺检测

目的利用响应面分析法优化刺参中金刚烷胺的检测。方法在单因素基础上,确定采用1%乙酸乙腈作为提取溶剂,以1%乙酸乙腈的添加量、超声时间、PSA吸附剂的添加量、C_(18)吸附剂的添加量为影响因素,以金刚烷胺的回收率为响应值,根据Box-Behnken试验设计原理对刺参中金刚烷胺提取条件进行响应面分析,优化前处理条件。结果1%乙酸乙腈为15 mL,超声提取10 min, PSA吸附剂为250 mg时刺参中金刚烷胺的回收率最大。在此优化条件下进行验证性试验,测得金刚烷胺的回收率为118%,与预测值相对误差为9.62%。实际检测刺参样品20个,2个样品检出,分别为4.3、1.6μg/kg。结论该优化前处理方法具有良好的可行性。     

Modeling of biodiesel production: Performance comparison of Box-Behnken,face central composite and full factorial design

The performances of the response surface methodology (RSM) in connection with the Box-Behnken, face central composite or full factorial design (BBD, FCCD or FFD, respectively) were compared for the use in modeling of the NaOH-catalyzed sunflower oil ethanolysis. The influence of temperature, catalyst loading, and ethanol-to-oil molar ratio (EOMR) on fatty acid ethyl esters (FAEE) content was evaluated. All three multivariate strategies were efficient in the statistical modeling and optimization of the influential process variables but BBD and FCCD realization involved less number of experiments, generating smaller costs, requiring less work and consuming shorter time than the corresponding FFD. All three designs resulted in the same optimal catalyst loading (1.25% of oil) and EOMR (12:1). The reduced two-factorinteraction (2FI) models based on the BBD and FCCD defined a range of optimal reaction temperature (25℃-75℃) and 25℃, respectively while the same model based on the 3³ FFD appointed 75℃. The predicted FAEE content of about 97%-98.0% was close to the experimentally obtained FAEE content of about 97.0%-97.6% under the optimal reaction conditions. Therefore, the simpler BBD or FCCD might successfully be applied for statistical modeling of biodiesel production processes instead of the more extensive, more laborious and more expensive FFD.