Optimization of L-asparaginase production from novel Enterobacter sp., by submerged fermentation using response surface methodology

The culture conditions and nutritional rations influencing the production of extra cellular antileukemic enzyme by novel Enterobacter aerogenes KCTC2190/MTCC111 were optimized in shake-flask culture. Process variables like pH, temperature, incubation time, carbon and nitrogen sources, inducer concentration, and inoculum size were taken into account. In the present study, finest enzyme activity achieved by traditional one variable at a time method was 7.6 IU/mL which was a 2.6-fold increase compared to the initial value. Further, the L-asparaginase production was optimized using response surface methodology, and validated experimental result at optimized process variables gave 18.35 IU/mL of L-asparaginase activity, which is 2.4-times higher than the traditional optimization approach. The study explored the E. aerogenes MTCC111 as a potent and potential bacterial source for high yield of antileukemic drug.     

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。     

响应面法快速优化曲霉Aspergillus sp.F044产脂肪酶培养条件

运用逐因子试验(Seriatim-Factorial Experiment)、Plackett-Burman、Response Surface Methodology(RSM)和单因子试验(Monofactorial Experiment)分析对产脂肪酶曲霉Aspergillus sp.F044产酶培养条件进行了快速优化。首先运用逐因子试验确定Aspergillus sp.F044产脂肪酶最适碳源和氮源,分别为麦芽糖和牛肉膏。在此基础上,通过Plackett-Burrman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橄榄油、牛肉膏、硫酸镁三个因素。然后通过实验拟合上述三因素与发酵液脂肪酶活力的一阶线性模型,沿着一阶模型给定的路径进行最速上升试验,在上升最高点处由中心组合试验和向应面分析确定其最优培养基组成;最后通过单因子试验确定最适发酵温度和摇床转速。试验优化的最优培养条件为:麦芽糖1.5%(w/v),硫酸铵7‰(w/v),磷酸氢二钾1‰(w/v),牛肉膏1.25%(w/v),硫酸镁2.11‰(w/v),橄榄油1.41%(v/v),自然pH,250r/min和30℃培养72h酶活达32.15U/mL。与初始11.18U相比,酶活提高2.88倍。     

Optimization of antifungal lipopeptide production from Bacillus sp. BH072 by response surface methodology

Antifungal lipopeptide produced by Bacillus sp. BH072 was extracted from fermentation liquor and determined as iturin A by liquid chromatography-mass spectrometry (LC-MS). For industrial-scale production, the yield of iturin A was improved by optimizing medium components and fermentation conditions. A one-factor test was conducted; fermentation conditions were then optimized by response surface methodology (RSM) to obtain the following: temperature, 29.5°C; pH 6.45; inoculation quantity, 6.7%; loading volume, 100 ml (in 500 ml flasks); and rotary speed, 150 rpm. Under these conditions, the mass concentration of iturin A was increased from 45.30 mg/ml to 47.87 mg/ml. The following components of the medium were determined: carbon sources (glucose, fructose, sucrose, xylose, rhamnose, and soluble starch); nitrogen sources (peptone, soybean meal, NH₄Cl, urea, and ammonium citrate); and metal ions (Zn²⁺, Fe³⁺, Mg²⁺, Mn²⁺, Ca²⁺, and K⁺). The effects of these components on iturin A production were observed in LB medium. We selected sucrose, soybean meal, and Mg²⁺ for RSM to optimize the conditions because of several advantages, including maximum iturin A production, high antifungal activity, and low cost. The optimum concentrations of these components were 0.98% sucrose, 0.94% soybean meal, and 0.93% Mg²⁺. After iturin A production was optimized by RSM, the mass concentration reached 52.21 mg/ml. The antifungal specific activity was enhanced from 350.11 AU/mg to 513.92 AU/mg, which was 46.8% higher than the previous result. The present study provides an important experimental basis for the industrial-scale production of iturin A and the agricultural applications of Bacillus sp. BH072.     

响应面分析法优化重组大肠杆菌生物合成谷胱甘肽的条件

通过响应面分析法和典型性分析得出重组大肠杆菌酶法合成谷胱甘肽的最优条件:菌体量249 mg/mL,磷酸钾缓冲液145 mmol/L,MgCl243 mmol/L和ATP 34 mmol/L,预测谷胱甘肽最大量为16.50 mmol/L。验证性实验证明在优化条件下,重组大肠杆菌酶法合成谷胱甘肽达16.42 mmol/L。响应面分析还表明,在重组大肠杆菌酶法合成谷胱甘肽各因素中,MgCl2和ATP,以及菌体量与磷酸钾缓冲液之间的交互作用较显著。     

Optimization of medium components for phytase production by E. coli using response surface methodology

The medium for recombinant phytase production by E. coli BL21 was optimized using response surface methodology. A 2³ central composite experimental design was used to study the combined effect of the medium components, tryptone, yeast extract and NaCl. Addition of 2?g/l glucose to the medium greatly influenced the phytase production. The optimization of the medium has increased the phytase production by 1.2 times. The incorporation of 2?g/l glucose significantly enhanced the phytase production by 1.58 times, showing an overall 2.78 fold increase before optimization and other modifications of the medium. The optimized medium with glucose showed a highest phytase activity of 2250?U/l.     

Optimization of galacto-oligosaccharide production by Bifidobacterium infantis RW-8120 using response surface methodology

Oligosaccharide (OS) production, cell concentration (2×10⁹ colony-forming unit/ml), lactose concentration (25% wt/vol), reaction time (6 h), and temperature (50°C) were chosen as the central condition of the central composite design (CCD) for optimizing the production process using Bifidobacterium infantis RW-8120 in skim milk. Statistical analysis (P<0.01) revealed that the most relevant variable concerning OS production and yield was the lactose concentration. The coefficient of determination (R ²) is good for the second-order OS production model (0.92) and fairly good for the second-order nonlinear OS yield model (0.816). An increase of lactose concentration and temperature resulted in a higher OS production. The optimal values for OS production appear to be near the area associated with the central points of the modeling design except for the lactose concentration, which was 40% (wt/vol) of the final volume. Received 29 March 2002/ Accepted in revised form 09 August 2002     

Optimization of light and temperature for growing Chlorella sp. using response surface methodology

Summary The simultaneous effect of temperature and photon flux density on microalga Chlorella sp. growth was analysed by response surface methodology of two consecutive full factorial designs. Maximum specific growth rate was 0.128 h^-1 at 35°C and 2400 mol photon m^-2s^-1. A photoinhibition effect was observed at high photon flux densities with temperatures far below the optimum. Temperature was the main factor affecting specific growth rate.     

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   

Optimization of exopolysaccharide welan gum production by Alcaligenes sp. CGMCC2428 with Tween-40 using response surface methodology

The effect of additives on welan gum production produced by fermentation with Alcaligenes sp. CGMCC2428 was studied. Tween-40 was the best additive for improving welan gum production and welan gum displayed better rheological properties than that obtained by control fermentation without additives. Response surface methodology was employed to optimize the culture conditions for welan gum production in the shake flask culture, including Tween-40 concentration, pH and culture temperature. The optimal conditions were determined as follows: Tween-40 concentration 0.94 g/l, pH 6.9 and temperature 29.6 °C. The corresponding experimental concentration of welan gum was 23.62 ± 0.60 g/l, which was agreed closely with the predicted value (23.48 g/l). Validation experiments were also carried out to prove the adequacy and the accuracy of the model obtained. The welan gum fermentation in a 7.5 l bioreactor reached 24.90 ± 0.68 g/l.     

Optimization of cold-active protease production by the psychrophilic bacterium Colwellia sp. NJ341 with response surface methodology

Culture conditions were optimized for an extracellular cold-active protease production by the psychrophilic bacterium Colwellia sp. NJ341. Response surface methodology was applied for the most significant fermentation parameters (casein, citrate sodium, temperature and Tween-80) identified earlier by one-factor-at-a-time approach. A 2(4) full factorial central composite design was employed to determine the maximum protease production. Using this methodology, the quadratic regression model of producing cold-active protease was built and the optimal combinations of media constituents for maximum protease production (183.21 U/mL) were determined as casein 5.18 g/L, citrate sodium 3.84 g/L, temperature 7.96 degrees C, Tween-80 0.23 g/L. Protease production obtained experimentally coincident with the predicted value and the model was proven to be adequate.     

Optimization of media composition for Nattokinase production by Bacillus subtilis using response surface methodology

Response surface methodology and central composite rotary design (CCRD) was employed to optimize a fermentation medium for the production of Nattokinase by Bacillus subtilis at pH 7.5. The four variables involved in this study were Glucose, Peptone, CaCl(2), and MgSO(4). The statistical analysis of the results showed that, in the range studied; only peptone had a significant effect on Nattokinase production. The optimized medium containing (%) Glucose: 1, Peptone: 5.5, MgSO(4): 0.2 and CaCl(2): 0.5 resulted in 2-fold increased level of Nattokinase (3194.25U/ml) production compared to initial level (1599.09U/ml) after 10h of fermentation. Nattokinase production was checked with fibrinolytic activity.     

Optimization of microbiological parameters for enhanced griseofulvin production using response surface methodology

Central composite design was used to determine the optimal levels of microbiological parameters, viz., slant age, seed age and inoculum level, for enhanced griseofulvin production by Penicillium griseofulvum MTCC 1898 and Penicillium griseofulvum MTCC 2004 in shake flask fermentation. The optimal levels of slant age, seed age and inoculum level for Penicillium griseofulvum MTCC 1898 were found to be 8.8772 days, 4.2093 days, 12% (v/v) (᷁.56 kg dry cell mass/m³) and for Penicillium griseofulvum MTCC 2004, 8.221 days, 3.4875 days and 9% (v/v) (̀.09 kg dry cell mass/m³) respectively. The yield of griseofulvin under optimal conditions was found to be 1.65 times for Penicillium griseofulvum MTCC 1898 and 1.07 times for Penicillium griseofulvum MTCC 2004 higher than that obtained using unoptimized conditions. The fermentation time for maximum production of griseofulvin by Penicillium griseofulvum MTCC 1898 and Penicillium griseofulvum MTCC 2004 decreased by 4 days and 2 days respectively.     

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 fermentation medium for amidase production by response surface methodology

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.运用单因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Ca2+、Mn2+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18.84 g/L、酵母浸膏9.55 g/L、NaCl 5g/L、KH2 PO41g/L、MgSO4·7H2O 0.2 g/L、FeSO40.001g/L、CaCO370.84 μmol/L、MnSO4 65.39 μmol/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4156 U/L,为原始发酵培养基配方酶活产量的1.63倍.     

Optimization of isoamyl acetate production by using immobilized lipase from Mucor miehei by response surface methodology

Immobilized lipase from Mucor miehei was employed for the esterification of isoamyl alcohol with acetic acid in n-heptane solvent. The important process variables studied were enzyme/substrate (E/S) ratio, alcohol (acid) concentration, and incubation period. Based on Box-Behnken design of experiments, a second order response function was developed. The percentage esterification increased with both E/S ratio and time and decreased with alcohol (acid) concentration. The model indicated optimum conditions for maximum esterification ranging from 20 to 99.6% in the alcohol (acid) concentration range of 0.031 to 0.3 M for a range of E/S ratios 8.33 to 50 g/mol, which were in good agreement with the experimental yields.     

Optimization of fermentative biohydrogen production by response surface methodology using fresh leachate as nutrient supplement

Fresh compost leachate was used as a nutrients source to facilitate anaerobic fermentative hydrogen production from glucose inoculated with mixed culture. The optimum condition for hydrogen production was predicted by response surface methodology (RSM). The model showed the maximum cumulative hydrogen volume (469.74 mL) and molar hydrogen yield (1.60 mol H₂/mol glucose) could be achieved at 6174.93 mg/L glucose and 3383.20 mg COD/L leachate. According to the predicted optimal condition, four tests were carried out to validate the predicted values and evaluate the leachate’s effect on co-fermentation with juice wastewater. A maximum cumulative hydrogen volume of 587.05 ± 15.08 mL was obtained in co-fermentation test, and the molar hydrogen yield reached 2.06 ± 0.06 mol H₂/mol glucose. The co-fermentation of fresh leachate and glucose/juice wastewater was a combination of acetic acid and butyric acid type-fermentation. The results demonstrated that leachate can serve as a nutrients source for biohydrogen production.     

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 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