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.     

响应面法优化耐高温酵母生产高浓度乙醇

利用耐高温酵母GXASY-10菌株对木薯粉同步糖化(SSF)法生产高浓度乙醇的发酵条件进行了优化。在单因素实验的基础上,首先应用Plackett-Burman试验设计筛选影响酒精高温高浓度发酵的重要参数,采用最陡爬坡实验逼近最大酒精生产区域后,利用Box-Behnken设计确定重要参数的最佳水平。筛选结果表明,影响酒精产量的重要参数是液化时间、糖化酶用量和初始木薯粉(底物)浓度。最佳工艺条件为:液化时间为35min,糖化酶添加量为1.21AGU/g底物,底物浓度为37.62%。20L发酵罐在此条件下(发酵温度37℃,转速100r/min)经过48h发酵,酒精浓度可达16.07%(V/W)。优化条件与初始条件相比较,酒精浓度提高了33%。     

响应面法优化玉米秸秆同步酶解发酵产乙醇条件

对汽爆玉米秸秆同步酶解发酵生产乙醇的条件进行优化。首先利用Fractional Factorial设计法对影响乙醇产量的7个因素进行评价,筛选出具有显著效应的3个因素,即反应温度、酶添加量、总反应时间,再以Box—Behnken设计法及响应面分析法确定主要因素的最佳水平,即反应温度37℃,每g纤维素添加纤维素酶32u,反应时间87h,此时乙醇体积分数达到3．69％。新工艺条件实验结果表明,乙醇体积分数在87h可达到3．76％,和原工艺相比,反应时间缩短了9h,乙醇体积分数提高了13％。     

Effect of C/N ratio and starch concentration on ethanol production from sago starch using recombinant yeast

Recombinant Saccharomyces cerevisiae YKU 131 (capable of expressing glucoamylase) was used to produce ethanol from sago starch. The optimum C/N ratio for ethanol production by the recombinant yeast was 7.9, where 4.7 and 10.1 g/l ethanol was produced from 20 and 40 g/l sago starch, respectively. At sago starch concentration higher than 40 g/l and C/N ratio higher than 10.4, glucoamylase production and rate of starch hydrolysis were reduced, which in turn, reduced ethanol production significantly. The theoretical yield of ethanol based on sago starch consumed in fermentation using 40 g/l was 72.6%. This yield was slightly lower than those obtained in fermentation using soluble starch such as potato and corn starch, which ranged from 80–90% as reported in the literature. However, S. cerevisiae YKU 131 could only utilize 62% of the total amount of starch added to a medium.     

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％。     

Box-Behnken响应面法优化司替霉素B产生菌发酵条件

【背景】粗糙链霉菌(Streptomyces scabrisporus) HBERC-53204是本中心自主分离的一株链霉菌,经鉴定,其产生一种活性化合物司替霉素B (steffimycin B,SMB),对多种动植物重要病原菌具有良好生物活性。【目的】提高SMB发酵水平,拓宽放线菌活性天然产物在农牧业领域的研究及应用。【方法】以本实验室筛选出的一株产SMB的粗糙链霉菌HBERC-53204为研究对象,运用单因素试验筛选培养基的主效碳源、氮源、无机盐及各营养成分最适浓度,并基于单因素试验结果,通过Plackett-Burman(PB)试验设计筛选出显著影响因素,再结合最陡爬坡试验、Box-Behnken (BB)响应面法拟合显著因子与产量的非线性方程求解,进一步优化菌株产SMB的最佳发酵培养基配方。【结果】优化后最佳培养基配方为：葡萄糖36.22 g/L,蛋白胨8.00 g/L,酵母粉8.51 g/L,酸水解酪蛋白1.50 g/L,MgSO₄ 0.68 g/L,KNO₃ 1.00 g/L。经摇瓶验证,优化后SMB效价达到477.26 mg/L...     

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%.     

High solid simultaneous saccharification and fermentation of wet oxidized corn stover to ethanol

In this study ethanol was produced from corn stover pretreated by alkaline and acidic wet oxidation (WO) (195 degrees C, 15 min, 12 bar oxygen) followed by nonisothermal simultaneous saccharification and fermentation (SSF). In the first step of the SSF, small amounts of cellulases were added at 50 degrees C, the optimal temperature of enzymes, in order to obtain better mixing condition due to some liquefaction. In the second step more cellulases were added in combination with dried baker's yeast (Saccharomyces cerevisiae) at 30 degrees C. The phenols (0.4-0.5 g/L) and carboxylic acids (4.6-5.9 g/L) were present in the hemicellulose rich hydrolyzate at subinhibitory levels, thus no detoxification was needed prior to SSF of the whole slurry. Based on the cellulose available in the WO corn stover 83% of the theoretical ethanol yield was obtained under optimized SSF conditions. This was achieved with a substrate concentration of 12% dry matter (DM) acidic WO corn stover at 30 FPU/g DM (43.5 FPU/g cellulose) enzyme loading. Even with 20 and 15 FPU/g DM (corresponding to 29 and 22 FPU/g cellulose) enzyme loading, ethanol yields of 76 and 73%, respectively, were obtained. After 120 h of SSF the highest ethanol concentration of 52 g/L (6 vol.%) was achieved, which exceeds the technical and economical limit of the industrial-scale alcohol distillation. The SSF results showed that the cellulose in pretreated corn stover can be efficiently fermented to ethanol with up to 15% DM concentration. A further increase of substrate concentration reduced the ethanol yield significant as a result of insufficient mass transfer. It was also shown that the fermentation could be followed with an easy monitoring system based on the weight loss of the produced CO2.     

马铃薯淀粉同步糖化发酵制备L-乳酸条件的统计学优化

以马铃薯淀粉为原料,采用同步糖化发酵方法制备乳酸。通过Plackett-Burman实验设计对影响乳酸产量的7个因子进行筛选,结果表明淀粉质量浓度、糖化酶用量和发酵温度3个因素对乳酸产量影响显著。利用最陡爬坡试验逼近最大响应区,采用中心复合实验设计及响应面分析法进行回归分析,建立影响乳酸产量的二次模型。模型求解得出最优淀粉质量浓度为271.89g/L,糖化酶用量为265.09U/g,发酵温度为39.05℃,最大理论乳酸产量为196.99g/L。3批验证实验结果平均值与预测值接近,表明该模型与实际情况拟合良好,实际最大乳酸产量为193.6g/L,较优化前提高了13.9%,L-乳酸的平均纯度达到95.2%。     

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。     

响应面法对微拟球藻产微藻蛋白的发酵条件优化

以稳定期微藻蛋白浓度为评价指标,利用响应面设计对微拟球藻(Nannochloropsis gaditana)的分批发酵条件进行优化。在单因素试验的基础上,选取温度、p H、搅拌速度及通气量为影响因子,采用四因素三水平的Box-Benhnken中心组合法设计试验。结果表明:微拟球藻的最佳发酵条件为温度30℃、p H 6.9、搅拌速度340 r/min以及通气量0.65 vvm,在此优化条件下得到微藻蛋白浓度为6.18 g/L,与模型预测值基本相符,较优化前提高了9.18%。     

响应面设计优化莱氏绿僵菌SZCY固体发酵培养条件及致病力测定

【背景】莱氏绿僵菌(Metarhizium rileyi)对新入侵我国的草地贪夜蛾(Spodoptera frugiperda)具有较强的致病力和田间流行性,因此具备深入开发的价值。【目的】优化莱氏绿僵菌SZCY固态发酵培养条件,测定所产分生孢子对草地贪夜蛾幼虫的毒力,为提高该菌株分生孢子规模化生产奠定基础。【方法】采用单因素试验确定了相对适宜的固态培养基,利用Box-Behnken响应面法优化该菌株的固态培养基和发酵参数,同时评价不同条件下该菌所产分生孢子对草地贪夜蛾幼虫的毒力。【结果】去颖稻谷(rice)为莱氏绿僵菌SZCY菌株固相产孢最佳载体。培养温度、光周期及酵母浸粉含量是影响莱氏绿僵菌SZCY固态发酵产孢量的主要因素。莱氏绿僵菌SZCY固态发酵最佳工艺参数为温度22.83℃、光周期18.68 h L:5.32 h D、酵母浸粉4.98 g/100 g,在此条件下,莱氏绿僵菌在去颖稻谷固态培养基上的产孢量为5.65×10¹⁰孢子/g,用其制备浓度为10⁷孢子/mL的孢子悬浮液,对草地贪夜蛾3龄幼虫的LT₅₀为3....     

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     

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％。     

Mathematical modelling of ethanol production from glucose/xylose mixtures by recombinant Zymomonas mobilis

A model has been developed for the fermentation of mixtures of glucose and xylose by recombinant Zymomonas mobilis strain ZM4(pZB5), containing additional genes for xylose assimilation and metabolism. A two-substrate model based on substrate limitation, substrate inhibition, and product (ethanol) inhibition was evaluated, and experimental data was compared with model simulations using a Microsoft EXCEL based program and methods of statistical analysis for error minimization. From the results it was established that the model provides good predictions of experimental batch culture data for 25/25, 50/50, and 65/65 g l^–1 glucose/xylose media.     

Optimization of fermentation condition for antibiotic production by Xenorhabdus nematophila with response surface methodology

Aims: To evaluate the influence of environmental parameters on the production of antibiotics (xenocoumacins and nematophin) by Xenorhabdus nematophila and enhance the antibiotic activity. Methods and Results: Response surface methodology (RSM) was employed to study the effects of five parameters (the initial pH, medium volume in flask, rotary speed, temperature and inoculation volume) on the production of antibiotics in flask cultures by X. nematophila YL001. A 2^5?1‐factorial central composite design was chosen to explain the combined effects of the five parameters and to design a minimum number of experiments. The experimental results and software‐predicted values of production of antibiotics were comparable. The statistical analysis of the results showed that, in the range studied, medium volume in flask, rotary speed, temperature and inoculation volume had a significant effect (P < 0·05) on the production of antibiotics at their individual level, medium volume in flask and rotary speed showed a significant influence at interactive level and were most significant at individual level. The maximum antibiotic activity was achieved at the initial pH 7·64, medium volume in 250 ml flask 25 ml, rotary speed of 220 rev min^?1, temperature 27·8°C and inoculation volume of 15·0%. Maximum antibiotic activity of 331·7 U ml^?1 was achieved under the optimized condition. Conclusions: As far as known, there are no reports of production of antibiotic from X. nematophila by engineering the condition of fermentation using RSM. The results strongly support the use of RSM for fermentation condition optimization. The optimization of the environmental parameters resulted not only in a 43·4% higher antibiotic activity than unoptimized conditions but also in a reduced amount of the experiments. The chosen method of optimization of fermentation condition was efficient, relatively simple and time and material saving. Significance and Impact of the Study: This study should contribute towards improving the antibiotics activity of X. nematophila. Integrated into a broader study of the impact of environmental factors on the production of antibiotic, this work should help to build more rational control strategy, possibly involving scale‐up of production of antibiotics by X. nematophila.     

Optimization of fermentation conditions for the production of ethanol from sago starch by co-immobilized amyloglucosidase and cells of Zymomonas mobilis using response surface methodology

Statistical experimental design was used to optimize the conditions of simultaneous saccharification and fermentation (SSF), viz. temperature, pH and time of fermentation of ethanol from sago starch with co-immobilized amyloglucosidase (AMG) and Zymomonas mobilis MTCC 92 by submerged fermentation. Maximum ethanol concentration of 55.3 g/l was obtained using a starch concentration of 150 g/l. The optimum conditions were found to be a temperature of 32.4 °C, pH of 4.93 and time of fermentation of 17.24 h. Thus, by using SSF process with co-immobilized AMG and Z. mobilis cells MTCC 92, the central composite design (CCD) was found to be the most favourable strategy investigated with respect to ethanol production and enzyme recovery.     

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。     

Statistical optimization of production conditions of alkaline pectin lyase from Bacillus cereus using response surface methodology

Alkaline pectin lyase finds applications in the degumming and retting of plant fibres, textile industry and pectic wastewater treatment where it degrades highly methylesterified pectin without prior action of any other pectinase. Response surface methodology (RSM) has been frequently utilized for the optimization of production process of industrially important enzymes from microbes. In the present work, fermentation conditions for the production of pectin lyase from Bacillus cereus were optimized using the factorial and central composite design of RSM. The cubic order polynomial regression model was found to be adequate and significant with a determination coefficient R² of 0.9505 (p?相似文献   

响应面分析法优化黑根霉胞外多糖发酵工艺

实验以商品化的马铃薯葡萄糖液体培养基为基础培养基,以胞外粗多糖产量为考察指标,运用响应面分析法考察玉米浆浓度、KH₂PO₄浓度和发酵时间3个因素对胞外多糖发酵产量的影响,以获得黑根霉胞外多糖发酵最优工艺,建立高产、稳定、可控的胞外多糖发酵生产工艺技术方案。经响应面分析,各因素按照对响应值的影响顺序为：玉米浆浓度>发酵时间> KH₂PO₄浓度,且玉米浆浓度、发酵时间对胞外多糖产量的影响极显著,KH₂PO₄浓度对胞外多糖产量的影响不显著。胞外多糖发酵最优工艺为：玉米浆3.2mg/mL、KH₂PO₄ 1.5mg/mL和发酵时间132h,在此条件下胞外多糖的最大预测产量为0.824mg/mL。实验重复性好,是一个高产、稳定、可控的胞外多糖发酵生产工艺技术方案,可以指导黑根霉胞外多糖发酵。