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%。     

Optimization of mycophenolic acid production in solid state fermentation using response surface methodology

Mycophenolic acid (MPA) can be produced in solid state fermentation. An isolate of Penicillium brevi-compactum ATCC 16024 grown on moist wheat bran produced a titre of 425 mg per kg of wheat bran. Central composite rotatable design and response surface methodology were employed to derive a statistical model for media optimization towards production of mycophenolic acid. Five levels with a five factorial design were adopted. The correlation coefficient was 0.82, ensuring a satisfactory adjustment of the model to the experimental values. This statistical design was very effective in improving the titre of mycophenolic acid up to 3286 mg per kg of wheat bran. Received 24 July 1998/ Accepted in revised form 4 December 1998     

Optimization of sugar release from sweet sorghum bagasse following solvation of cellulose and enzymatic hydrolysis using response surface methodology

To release sugars effectively from sweet sorghum bagasse (SSB), a cellulose solvent and organic solvent‐based lignocellulose fractionation pretreatment approach was studied using response surface methodology (RSM). Based on RSM's central composite design, a batch experimental matrix was set up to determine the effects of reaction time (20–60 min) and temperature (40–60 °C) on delignification, total reducing sugar yield, glucan digestibility, and overall glucose yields following a pretreatment‐hydrolysis process. The optimum pretreatment conditions of 50 °C and 40 min led to 51.4% delignification, 86% overall glucose yield, and 61% overall xylose yield. An effort has also been made to obtain predictive models to illustrate the correlation between independent and dependent variables using RSM. The significance of the correlations and adequacy of these models were statistically tested for the selected objective functions. The optimum pretreatment condition predicted by the model was 49.1 °C and 39.2 min which matched the experimental data well. Results from this study can be applied to large scale biorefineries using sugars released from SSB for producing various biofuels. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 30:367–375, 2014     

Optimization of enzymatic hydrolysis of mango kernel starch by response surface methodology

Amyloglucosidase (EC 3.2.1.3) from Aspergillus niger was employed for the saccharification of mango (Mangifera indica Linn) kernel starch. Response surface methodology based on a three-level three-factor Box-Behnken design was employed to optimize the important process variables such as substrate concentration (137.5-412.5 mg), enzyme concentration (4-12 mg) and temperature (35-55 °C). The sugar yield increased with both enzyme concentration and temperature, and decreased with substrate concentration. The response surface model indicated optimum conditions (substrate, 137.5 mg; enzyme, 12 mg; temperature, 55 °C) for obtaining 0.4851 mg sugar/mg substrate, which was also verified experimentally.     

Optimization of culture conditions for production of cis-epoxysuccinic acid hydrolase using response surface methodology

Response surface methodology, which allows for rapid identification of important factors and optimization of them to enhance enzyme production, was employed here to optimize culture conditions for the production of cis-epoxysuccinic acid hydrolase from Bordetella sp. strain 1–3. In the first step, a Plackett–Burman design was used to evaluate the effects of nine variables (yeast extract, cis-epoxysuccinic acid, KH₂PO₄, K₂HPO₄ · 3H₂O, MgSO₄ · 7H₂O, trace minerals solution, culture volume, initial pH and incubation time) on the enzyme production. Yeast extract, cis-epoxysuccinic acid and KH₂PO₄ had significant influences on cis-epoxysuccinic acid hydrolase production and their concentrations were further optimized using central composite design and response surface analysis. A combination of adjusting the concentration of yeast extract to 7.8 g/l, cis-epoxysuccinic acid to 9.8 g/l, and KH₂PO₄ to 1.12 g/l would favor maximum cis-epoxysuccinic acid hydrolase production. An enhancement of cis-epoxysuccinic acid hydrolase production from 5.6 U/ml to 9.27 U/ml was gained after optimization.     

响应面法优化芦荟中抗氧化活性成分的提取工艺

对芦荟中抗氧化活性物质提取工艺及其成分进行研究,通过单因素实验和响应面优化,以提取物对DPPH自由基的清除率为抗氧化的考察指标,得到芦荟中抗氧化活性成分的提取工艺条件:提取温度29 ℃、料液比(g/mL)1:33、提取时间107 s、微波功率500 W,微波辅助水提,此条件下得到的提取物对DPPH自由基的清除率达91.414%.提取物活性成分分析表明:提取物中芦荟甙含量为1.5 mg/g、黄酮为1.13 mg/g、多酚为4.33 mg/g、多糖为126.36 mg/g.     

Optimization of protein extraction from Gelidiella acerosa by carbohydrases using response surface methodology

In this study, application of response surface methodology for enzymic pretreatment optimization of Gelidiella acerosa was investigated in order to improve the extraction of algal proteins using Viscozyme L and Celluclast 1.5L. The total protein, soluble proteins and reducing sugar recovery in the water‐soluble fraction were studied in relation to the hydrolysis time, type and concentration of the enzymes. Enzymatic digestion appeared to be an effective treatment for protein extraction. While enzyme hydrolysis by Celluclast 1.5L was able to facilitate the protein extraction, it was a relatively inefficient way to improve protein extraction yield, in comparison with Viscozyme L. The optimum conditions for protein extraction was found to be hydrolysis by 2.8 μL mL^?1 of Viscozyme L for 12 h.     

Optimization of recombinant hyperthermophilic esterase production from agricultural waste using response surface methodology

The aim of this work was to evaluate the capability of corn steep liquor being a low cost substrate on the recombinant protein production by cultivating recombinant Escherichia coli and increasing the production of hyperthermophilic esterase (HE). The effect of corn steep liquor, mineral salt and trace metals on hyperthermophilic esterase production was investigated by means of a five-level three-factor central composite rotatable design. Optimized values of the factors were determined and a maximum hyperthermophilic esterase production of 251.39 U/ml was obtained. This value equaled the yield by yeast extract and peptone medium on the whole.     

Optimization of laccase production from a novel strain-Streptomyces psammoticus using response surface methodology

Response surface methodology was employed for the optimization of different nutritional and physical parameters for the production of laccase by the filamentous bacteria Streptomyces psammoticus MTCC 7334 in submerged fermentation. Initial screening of production parameters was performed using a Plackett - Burman design and the variables with statistically significant effects on laccase production were identified. Incubation temperature, incubation period, agitation rate, concentrations of yeast extract, MgSO(4)7H(2)O, and trace elements were found to influence laccase production significantly. These variables were selected for further optimization studies using a Box-Behnken design. The statistical optimization by response surface methodology resulted in a three-fold increase in the production of laccase by S. psammoticus MTCC 7334.     

Optimization of ultrasonic circulating extraction of polysaccharides from Asparagus officinalis using response surface methodology

Polysaccharides were extracted from Asparagus officinalis. A novel ultrasonic circulating extraction (UCE) technology was applied for the polysaccharide extraction. Three-factor-three-level Box-Behnken design was employed to optimize ultrasonic power, extraction time and the liquid-solid ratio to obtain a high polysaccharide yield. The optimal extraction conditions were as follows: ultrasonic power was 600 W, extraction time was 46 min, the liquid-solid ratio was 35 mL/g. Under these conditions, the experimental yield of polysaccharides was 3.134%, which was agreed closely to the predicted value. The average molecular weight of A. officinalis polysaccharide was about 6.18 × 10⁴ Da. The polysaccharides were composed of glucose, fucose, arabinose, galactose and rhamnose in a ratio of 2.18:1.86:1.50:0.98:1.53. Compared with hot water extraction (HWE), UCE showed time-saving, higher yield and no influence on the structure of asparagus polysaccharides. The results indicated that ultrasonic circulating extraction technology could be an effective and advisable technique for the large scale production of plant polysaccharides.     

Optimization of methane fermentation from effluent of bio-hydrogen fermentation process using response surface methodology

The individual effects and interactive effects of substrate concentration, ratio of inoculum to substrate, Ca(2+) concentration on the methane yield from the effluent of bio-hydrogen fermentation of food waste were investigated in this study. A central composite design (CCD) and response methodology (RSM) were employed in designing the experiments, in order to determine the optimum conditions for methane fermentation. The experiment results showed that the effects of substrate concentration, ratio of inoculum to substrate, Ca(2+) concentration were statistically significant at 5% level. The interactive effect of substrate concentration and ratio of inoculum to substrate was significant, however the interactive effect of substrate concentration and Ca(2+) concentration, ratio of inoculum to substrate and Ca(2+) concentration were found to be insignificant at 5% level. A maximum yield of 565.76 ml CH(4)/g VS(added) was estimated under the optimum conditions for substrate concentration 7.77 g of VS/l, inoculum to substrate ratio of 2.81 and calcium concentration of 380.82 mg/l. Verification experiment of the estimated optimum conditions confirmed that the RSM was useful for optimizing the methane yield from effluent of bio-hydrogen fermentation of food waste.     

Optimization of polyphenol extraction from red grape pomace using aqueous glycerol/tartaric acid mixtures and response surface methodology

Grape pomace is a food industry waste containing a high burden of antioxidant polyphenols and several methodologies have been developed for their efficient extraction. However, a sustainable and environmentally friendly process should involve recovery means composed of benign, non-toxic solvents, such as tartaric acid and glycerol, which are natural food constituents. In this line, this study examined the extraction of polyphenols using aqueous tartaric acid/glycerol solutions. The aim was to assess the role of acid and glycerol concentration in the extraction yield, employing a Box-Behnken experimental design and response surface methodology. The results showed that solutions containing only glycerol (20%, w/v) are more suitable for retrieving polyphenols, flavonoids, and pigments from grape pomace, while tartaric acid exerted a negative effect in this regard, when tested at concentrations up to 2% (w/v).     

Optimization of transesterification of animal fat ester using response surface methodology

In an effort to optimize the reaction conditions of biodiesel production from lard, response surface methodology was applied, and the effects of five-level-three-factors and their reciprocal interactions were assessed. A total of 20 individual experiments were conducted, and were designed to study reaction temperature, catalyst amount, and oil-to-methanol molar ratio. A statistical model predicted that the highest conversion yield of lard biodiesel would be 98.6%, at the following optimized reaction conditions: a reaction temperature of 65 degrees C, a catalyst amount of 1.26%, and an oil-to-methanol molar ratio of 7.5:1, with a 20-min reaction time. Using these optimal factor values under experimental conditions in three independent replicates, an average content of 97.8+/-0.6% was achieved, and this value was well within the range predicted by the model. The quality of biodiesel produced from lard at the optimum reaction conditions satisfied the relevant quality standards, with the exception of cold filter plugging point.     

Optimization of flocculation conditions for Botryococcus braunii using response surface methodology

Biodiesel from microalgae is recognized as a desirable, renewable biofuel to replace petroleum-derived transport fuels. However, the efficient harvesting of microalgae is a major hurdle for commercialization. Therefore, the development of a cost-effective harvesting method is essential to reduce production cost. A partial factorial design was used to screen the main factors involved, which were the concentration of FeCl₃, the bioflocculant, and the time of slow mixing. Response surface methodology (RSM) was used to further investigate the optimal conditions for these factors on flocculation of Botryococcus braunii. Analysis of variance and other relevant tests confirmed the validity of the suggested model. The optimal conditions inferred from the obtained equation were 0.79 mM FeCl₃, 0.58 % (v/v) bioflocculant, and 180 sec of slow mixing for 1.1 g DCW L^?1 of B. braunii. The flocculating activity under these conditions was 90.6 %. By using RSM, the optimal conditions for flocculation of B. braunii could be reached more quickly and efficiently.     

Optimization of fermentation parameters in phage production using response surface methodology

Previously, we used computer-controlled fermentation technology to improve the yield of filamentous phage produced in Escherichia coli by 10-fold (Grieco et?al., Bioprocess Biosyst Eng 32:773-779, 2009). In the current study, three major fermentation parameters (temperature, dissolved oxygen [DO], and pH) were investigated using design of experiments (DOE) methodology. Response surface methodology (RSM) was employed to create a process model and determine the optimal conditions for maximal phage production. The experimental data fitted best to a quadratic model (p?相似文献   

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。     

产S-酰胺酶培养基统计学筛选与响应面优化

利用Design Expert软件中的两水平实验设计和响应面法,对发酵生产S-酰胺酶(可用于拆分2,2-二甲基环丙甲酰胺外消旋体)的培养基进行了优化。采用Plackett-Burman(PB)设计对培养基中相关影响因素的效应进行评价并筛选出了有显著效应的葡萄糖、酵母粉及2,2-二甲基环丙甲酰胺浓度,其他因素对酰胺酶产量的影响不显著。然后用旋转中心组和实验设计及响应面分析确定了主要影响因素的最佳条件,在优化的培养基中,酰胺酶产量达到168 U/L,比优化前的80 U/L提高了110.0%。     

响应面设计法优化单葡萄糖醛酸基甘草次酸（GAMG）发酵转化培养基

以甘草酸（dycyfrhizin,GL）为底物,利用产紫青霉（Penicillium purpurogenum Li-3）液态发酵转化单葡萄糖醛酸甘草次酸（GAMG）,采用响应面设计法对初始发酵培养基进行优化。用部分因子分析法研究原始发酵培养基各成分对响应值的显著程度,发现甘草酸（GL）、NaNO3和K2HPO4的质量浓度对发酵产生GAMG的影响显著（P〈0．01）。用中心组合设计确立甘草酸、NaNO3和K2HPO4的适宜质量浓度分别为2．8、3．0和0．8g／L。在优化条件下进行发酵时,GAMG的转化率从75．49％提高到89．11％,比优化前提高了13．62％。