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。     

洋葱伯克霍尔德菌发酵产抗菌物质CF66I温度控制策略

在3.7 L发酵罐中考察了不同温度23℃～33℃对洋葱伯克霍尔德菌CF-66发酵产抗菌物质CF66I的影响,并对不同温度下的发酵过程进行了动力学特性分析。在此基础之上,提出抗菌物质CF66I合成的分阶段控制策略：发酵过程0～20 h控制温度在30℃,20 h后温度控制在25℃至发酵结束。采用此温度控制策略进行了CF66I的发酵,CF66I的活性达到了3.783 u/mL,比采用单一温度下的最大值提高了26.1%。     

细菌素发酵培养基的优化及动力学初步分析

用响应面方法对Lactococcus lactis生产细菌素乳链菌肽的培养基进行了优化。首先用部分重复因子实验对培养基组份蔗糖,大豆蛋白胨,酵母粉,KH₂PO₄,NaCl,MgSO₄·7H2O对乳链菌肽的影响进行评价,并找出主要影响因子为大豆蛋白胨和磷酸二氢钾,前者为负影响,后者为正效应,其它组份对乳链菌肽产量的影响不显著。第二步用最陡爬坡路径逼近最大响应区域。最后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。菌株在优化培养基中的乳链菌肽产量增加1倍为2150(IU/mL)。动力学分析表明,菌株生长与细菌素的产生为部分耦联型,进入对数中期菌体比生长速率和细菌素比产率在优化培养基中均大于优化前培养基。     

4-丁内酰胺水解酶法制备γ-氨基丁酸

以吡咯烷酮为唯一碳源,从采集的土样中分离、筛选得到具有4-丁内酰胺水解酶活性的菌株.采用响应面分析法对该菌株的产酶培养基组分进行了优化研究并对酶促转化反应条件也进行了研究.结果表明:编号为HHSW-16的菌株水解活性最高.优化后的培养基组成为:葡萄糖11.50 g·L-1,牛肉膏6.35 g·L-1,酵母粉5.58 g...     

响应面法优化热带假丝酵母104菌株产羰基还原酶发酵培养基

通过菌种优选得到产高选择性羰基还原酶的热带假丝酵母(Candida tropicalis)104菌株,可不对称还原1-(3,5-二三氟甲基)苯基乙酮生成(S)-1-(3,5-二三氟甲基)苯基乙醇,对映体过量值>99.9%。采用部分因子实验设计考察发酵培养基中各组分对产酶的影响,结果表明,酵母粉、葡萄糖和NH4Cl浓度对产酶影响显著。继而采用最陡爬坡路径逼近最大响应区域,并结合中心组合实验和响应面对3个显著性因素进行分析,得到优化的发酵培养基组成:葡萄糖47.14g/L,酵母粉13.25g/L,NH4Cl2.71g/L,MgSO4·7H2O0.4g/L,KH2PO41g/L和K2HPO41g/L。采用该优化培养基,供试菌株的羰基还原酶活力达851.13U/L,较优化前提高了65.2%。     

表皮短杆菌ZJB-07021产R-酰胺酶培养条件的优化

采用响应面分析法(RSM)对R-酰胺酶产生菌Brevibacterium epidermidis ZJB-07021的发酵培养基进行了优化.首先运用了单因子试验筛选出了发酵培养的最佳pH与温度,在此基础上采用Plackett-Burman(PB)设计法,对 8 种影响产酶的因素进行评价,实验结果表明,葡萄糖、酵母粉与乙酰胺含量对菌株产酰胺酶的活力具有显著的影响.通过旋转中心组合实验考察了葡萄糖、酵母粉和乙酰胺这三个主要因素对菌株所产酰胺酶活力的影响.发酵培养基优化结果为葡萄糖 17.00 g/L,酵母粉 15.74 g/L,乙酰胺 7.05 g/L,采用优化后的发酵培养条件进行摇瓶发酵培养,酰胺酶的酶活达到 72.14 U/L,比优化前的初始发酵培养条件下的酶活提高了73.3%.     

一株Bacillus sublitisJH-1发酵产木聚糖酶培养基的响应面优化

利用刚果红透明圈法从秸秆堆肥中筛选出一株产木聚糖酶菌株Bacillus sublitis JH-1,以单因素试验为基础,采用响应面试验设计对Bacillus sublitis JH-1液态发酵产木聚糖酶的培养基进行了优化,得到产木聚糖酶发酵最适条件为:培养温度33℃,p H值6.0,麦芽糖浓度为2.6%,酵母粉浓度为1.2%,KH2PO4浓度为1.2%,发酵产酶量比优化前提高了1.8倍。     

内生解淀粉芽孢杆菌CC09产Iturin A摇瓶发酵条件优化

【目的】提高内生解淀粉芽孢杆菌CC09发酵产抗菌脂肽Iturin A的产量。【方法】首先采用单因子实验研究了碳源、氮源、NaCl浓度、pH、温度、转速和装液量等因子对CC09产Iturin A能力的影响,然后对其中显著性因子:氮源浓度、pH、温度及装液量4个因素进行正交实验,进一步优化发酵条件。【结果】优化培养基组成及发酵条件可以提高CC09菌株的生长速度及产Iturin A的量,其中可溶性淀粉以及一定比例的蛋白胨和酵母粉是CC09菌株产Iturin A的良好碳源和氮源;培养温度、装液量、培养液pH等也对CC09菌株产Iturin A有显著影响。优化后的培养基成分:可溶性淀粉(碳源)5 g/L、比例为3:1的胰蛋白胨酵母粉混合氮源15 g/L、NaCl 1 g/L;最佳培养条件:pH 6.0、28°C、摇床转速120 r/min、培养瓶装液量20%。【结论】在此条件下,Iturin A的产量可达到690 mg/L,较优化前的138 mg/L提高了4倍。     

响应面法优化波赛链霉菌JMC 06001发酵培养基

采用响应面法对产生抑菌活性物质的波赛链霉菌（Streptomyces peucetius）菌株JMC 06001的发酵培养基进行优化。首先采用Minnimum Run Equireplicated Res IV设计对初始发酵培养基的8个营养因素进行筛选,获得影响产生抑菌活性物质的3个主要影响因素：葡萄糖、大豆粉和NaCI;然后用最陡爬坡实验快速逼近最大响应区域;最后,结合Box-Behnken设计及响应面分析,确定主要影响因素的最佳浓度,得出该菌株产抑菌活性物质的最优发酵培养基配方为：葡萄糖1．2％,麦芽糖0．7％,蛋白胨0．9％,大豆粉1．4％,NaCl3．7％,CaCO3 0．1％,复合盐A液2．0％,复合盐B液0．1％,起始pH值7．0。用优化后的培养基发酵所得发酵液对敏感指示菌藤黄八叠球菌的抑菌圈直径达31．5mm,与预测值的相对偏差仅为1．59％,与用初始发酵培养基发酵所得发酵液的抑菌效果（抑菌圈直径26．5mm）相比提高了18．9％。     

响应面法优化黑曲霉产果胶酶培养基中无机盐成分的研究

利用SAS软件中的二水平设计和响应面分析方法较系统地研究了发酵培养基中无机盐组分对黑曲霉(Aspergillus niger)JW-1菌株产果胶酶的影响.得到了在一定条件下果胶酶随无机盐组分的变化规律,并根据分析结果优化了产酶培养基.最终确定KH_2PO_4,FeSO_4·7H_2O,CaCl_2·2H_2O的最优浓度分别为0.85mg/mL,1.86mg/mL和2.52mg/mL,此时果胶酶活力可达5054.6U·g~(-1),为该菌株今后的研究和应用奠定了基础.     

Screening and optimization of nutritional factors for higher dextransucrase production by Leuconostocmesenteroides NRRL B-640 using statistical approach

To improve dextransucrase production from Leuconostocmesenteroides NRRL B-640 culture medium was screened and optimized using the statistical design techniques of Plackett-Burman and response surface methodology (RSM). Plackett-Burman design with six variables viz. sucrose, yeast extract, K2HPO4, peptone, beef extract and Tween 80 was performed to screen the nutrients that were significantly affecting dextransucrase production. The variables sucrose, K2HPO4, yeast extract and beef extract showed above 90% confidence levels for dextransucrase production and were considered as significant factors for optimization using response surface methodology. 2(4)-central composite design was used for RSM optimization. The experimental results were fitted to a second-order polynomial model which gave a coefficient of determination R2=0.95. The optimized composition of 30g/l sucrose, 18.9g/l yeast extract, 19.4g/l K2HPO4 and 15g/l beef extract gave an experimental value of dextransucrase activity of 10.7U/ml which corresponded well with the predicted value of 10.9U/ml by the model.     

Optimization of medium composition and culture conditions for agarase production by Agarivorans albus YKW-34

Effect of medium composition and culture conditions on agarase production by Agarivorans albus YKW-34 was investigated in shake flasks. The most suitable carbon source, nitrogen source, and culture temperature were agar, yeast extract, and 25 °C, respectively, for agarase production by one-factor-at-a-time design. The nutritional components of the medium and culture conditions were analyzed by Plackett–Burman design. Among the nine factors studied, agar, yeast extract, and initial pH had significant effects on agarase production (p < 0.05). The optimum levels of these key variables were further determined using a central composite design. The highest agarase production was obtained in the medium consisting of 0.23% agar and 0.27% yeast extract at initial pH 7.81. The whole optimization strategy enhanced the agarase production from 0.23 U/ml to 0.87 U/ml. The economic medium composition and culture condition as well as the dominant occupation of agarase with high activity in culture fluid enlighten the potential application of A. albus YKW-34 for the production of agarase.     

Augmented cellulase production by Bacillus subtilis strain MU S1 using different statistical experimental designs

The production of cellulase by Bacillus subtilis MU S1, a strain isolated from Eravikulam National Park, was optimized using one-factor-at-a-time (OFAT) and statistical methods. Physical parameters like incubation temperature and agitation speed were optimized using OFAT and found to be 40?°C and 150?rpm, respectively, whereas, medium was optimized by statistical tools. Plackett-Burman design (PBD) was employed to screen the significant variables that highly influence cellulase production. The design showed carboxymethyl cellulose (CMC), yeast extract, NaCl, pH, MgSO₄ and NaNO₃ as the most significant components that affect cellulase production. Among these CMC, yeast extract, NaCl and pH showed positive effect whereas MgSO₄ and NaNO₃ were found to be significant at their lower levels. The optimum levels of the components that positively affect enzyme production were determined using response surface methodology (RSM) based on central composite design (CCD). Three factors namely CMC, yeast extract and NaCl were studied at five levels whilst pH of the medium was kept constant at 7. The optimal levels of the components were CMC (13.46?g/l), yeast extract (8.38?g/l) and NaCl (6.31?g/l) at pH 7. The maximum cellulase activity in optimized medium was 566.66?U/ml which was close to the predicted activity of 541.05?U/ml. Optimization of physical parameters and medium components showed an overall 3.2-fold increase in activity compared to unoptimized condition (179.06?U/ml).     

Production of glutaminase (E.C.3.2.1.5) from Zygosaccharomyces rouxii: statistical optimization using response surface methodology

A face centered central composite design was employed to investigate the interactive effects of four variables, viz. concentrations of sucrose, yeast extract, sodium chloride, and glutamine, identified earlier by one-factor-at-a-time approach, on glutaminase production by Zygosaccharomyces rouxii. A significant influence of yeast extract on glutaminase production was noted. Response surface methodology (RSM) showed that a medium containing (g/l) sucrose, 17.8; yeast extract, 48.0; glutamine, 5.0 and sodium chloride, 55.6 to be optimum for the production of glutaminase. This medium was projected to produce, theoretically, an enzyme activity of 149.98 U/l and a specific activity of 0.488 U/mg protein. The applied methodology was validated using this optimized media and enzyme activity 155.89+/-1.68 U/l and specific activity of 0.468+/-0.088 U/mg protein was obtained. Further, this optimization strategy combined with an increase in inoculum enhanced the enzyme activity and specific activity by 2.94 and 3.58 fold, respectively, as compared to the unoptimized media.     

Response surface optimization of the critical medium components for carbonyl reductase production by Candida viswanathii MTCC 5158

Culture conditions were optimized for the growth and carbonyl reductase production by a novel yeast strain Candida viswanathii. Response surface methodology was applied for the critical medium components (initial pH, mannitol, yeast extract and calcium chloride) identified earlier by one-factor-at-a-time approach. Central composite design was used for the optimization studies. Using this methodology, the optimal values for the concentration of mannitol, initial pH, yeast extract and calcium chloride were 1.9, 7.5, 1.6 and 4, respectively. This medium was projected to produce, theoretically, growth having an optical density of 1.1 (600 nm) and an enzyme activity of 81.5 U/ml. Using this optimized medium, an experimental growth of 1.1 OD (600 nm) and enzyme activity 80.9 U/ml verified the applied methodology. This approach for medium optimization led to an enhancement of the growth and enzyme activity by 1.3 and 2.3 times higher, respectively, as compared to the unoptimized media.     

Optimization of alkaline protease production by <Emphasis Type="Italic">Aspergillus clavatus</Emphasis> ES1 in <Emphasis Type="Italic">Mirabilis jalapa</Emphasis> tuber powder using statistical experimental design

Medium composition and culture conditions for the bleaching stable alkaline protease production by Aspergillus clavatus ES1 were optimized. Two statistical methods were used. Plackett-Burman design was applied to find the key ingredients and conditions for the best yield. Response surface methodology (RSM) including full factorial design was used to determine the optimal concentrations and conditions. Results indicated that Mirabilis jalapa tubers powder (MJTP), culture temperature, and initial medium pH had significant effects on the production. Under the proposed optimized conditions, the protease experimental yield (770.66 U/ml) closely matched the yield predicted by the statistical model (749.94 U/ml) with R (2)=0.98. The optimum operating conditions obtained from the RSM were MJTP concentration of 10 g/l, pH 8.0, and temperature of 30 degrees C, Sardinella heads and viscera flour (SHVF) and other salts were used at low level. The medium optimization contributed an about 14.0-fold higher yield than that of the unoptimized medium (starch 5 g/l, yeast extract 2 g/l, temperature 30 degrees C, and pH 6.0; 56 U/ml). More interestingly, the optimization was carried out with the by-product sources, which may result in cost-effective production of alkaline protease by the strain.     

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 medium composition for alkali-stable xylanase production by Aspergillus fischeri Fxn 1 in solid-state fermentation using central composite rotary design

Response surface methodology and central composite rotary design (CCRD) was employed to optimize a fermentation medium for the production of alkali-stable cellulase-free xylanase by Aspergillus fischeri in solid-state fermentation at pH 9.0 with wheat bran as substrate. The four variables involved in this study were sodium nitrite, potassium dihydrogen phosphate, magnesium sulphate and yeast extract. The statistical analysis of the results showed that, in the range studied, only sodium nitrite had a significant effect on xylanase production. The optimized medium containing (in g/l) NaNO(2)-7.0, K2HPO(4)-1.0, MgSO(4)-0.5 and yeast extract-5.0 resulted in 1.9-fold increased level of alkali-stable xylanase (1024 U/g wheat bran) production compared to initial level (540 U/g) after 72 h of fermentation, whereas its value predicted by the quadratic model was 931 U/g. The level of protease activity was considerably decreased in optimized medium, thus helping to preserve the xylanase activity and demonstrating another advantage of applying statistical experimental design.     

Inulinase production and mathematical modeling from carob extract by using Aspergillus niger

The main objectives of the study were to produce inulinase from carob extract by Aspergillus niger A42 (ATCC 204447) and to model the inulinase fermentation in the optimum carob extract-based medium. In the study, carob extract was used as a novel and renewable carbon source in the production of A. niger inulinase. For medium optimization, eight different variables including initial sugar concentration (°Bx), (NH₄)₂HPO₄, MgSO₄.7H₂O, KH₂PO₄, NH₄NO₃, yeast extract, peptone, and ZnSO₄.7H₂O were employed. After fermentations, optimum medium composition contained 1% yeast extract in 5°Bx carob extract. As a result of the fermentation, the maximum inulinase activity, maximum invertase-type activity, I/S ratio, maximum inulinase- and invertase-type activity rates, maximum sugar consumption rate, and sugar utilization yield were 1507.03 U/ml, 1552.86 U/ml, 0.97, 175.82 and 323.76 U/ml/day, 13.26 g/L/day, and 98.52%, respectively. Regarding mathematical modeling, the actual inulinase production and sugar consumption data were successfully predicted by Baranyi and Cone models based on the model evaluation and validation results and the predicted kinetic values, respectively. Consequently, this was the first report in which carob extract was used in the production of inulinase as a carbon source. Additionally, the best-selected models can serve as universal equations in modeling the inulinase production and sugar consumption in shake flask fermentation with carob extract medium.