星点设计-效应面法优化凤尾草总黄酮超声提取工艺

目的:星点设计-效应面法优化凤尾草总黄酮的提取工艺。方法:采用超声波提取法提取,在单因素试验的基础上,以乙醇浓度(%)、提取时间(分钟)和料液比(倍数)为自变量,以凤尾草中总黄酮提取率为考察量,利用线性多元回归和拟合二项式方程对自变量不同因素水平进行预测,设计星点设计-效应面法优化最佳提取工艺,并预测分析结果。结果:最佳提取工艺为乙醇浓度63.7%,提取时间25.80min,液料比44.47倍。凤尾草总黄酮提取率预测值为1.831%,与实际值1.814%的偏差为-0.928%。结论:试验设计简便合理,稳定可行,可预测性好。     

复合酶提取香菇多糖的研究

采用蛋白酶和纤维素酶两种复合酶处理,对酶液的用量(蛋白酶浓度为8%、纤维素酶为4%),料液比,最适pH值,反应时间进行单因子和正交试验.确定了复合酶法提取香菇多糖的最佳工艺为:料液比1∶25,pH值4.8,酶液量0.35ml(蛋白酶浓度为8%、纤维素酶为4%),反应时间1.5h,多糖提取率为15.13%,比起传统水提法有大幅提高.     

女贞子多糖的提取优化工艺研究

目的:研究女贞子多糖的提取优化工艺。方法:在复合酶辅助前提下,以女贞子多糖提取率为指标,在单因素考察的基础上,采用正交试验法优化女贞子多糖的提取工艺。结果:各因素对提取工艺的影响顺序:料液比提取时间p H值提取温度;最佳提取工艺为复合酶(纤维素酶:木瓜蛋白酶=1∶2)添加量为2.0%,料液比为1∶50,提取时间为1.0 h,p H为4,提取温度为50℃。此条件得到的多糖提取率达到15.93%。结论:通过验证结果表明该优选工艺合理、稳定、重现性好,条件温和,易于实现放大,可为女贞子多糖的生产实践提供参考依据。     

凤尾草总黄酮超声波提取工艺研究

目的:研究超声波提取法对凤尾草总黄酮的优化作用,确定最佳的工艺条件和参数。方法:利用超声波提取技术,以凤尾草总黄酮含量为指标,以提取温度、提取时间、提取次数、乙醇浓度及料液比5个因素设计正交实验,每个因素设计4个水平,优选凤尾草超声波提取法工艺。结果:最佳工艺条件为提取温度70℃,提取时间20 min,提取次数4次,乙醇浓度80%,料液比为1∶15。结论:该项研究可为凤尾草总黄酮提取工艺提供参考。     

正交试验联用星点设计-效应面法优化西瓜皮总黄酮提取工艺研究

以总黄酮得率为指标,采用正交试验联合星点设计-效应面法考察乙醇体积分数、提取时间和固液比对西瓜皮总黄酮提取工艺的影响。结果表明正交试验确定最佳提取工艺为30倍量90％乙醇,提取3次,每次120min;星点设计一效应面法确定最佳提取工艺为14.22倍量71.17％乙醇,提取3次,每次48.25min。通过星点设计-效应面法优选的工艺合理可行,且比正交试验设计法更为准确。     

微波辅助提取红菇多糖的工艺条件优化

为提高红菇多糖得率,在单因素试验基础上,选择料液比、微波温度、微波时间为自变量,通过正交试验确定得到微波辅助提取红菇多糖的最佳工艺条件为:料液比为1∶40,微波时间为400 s,微波温度设定60℃,浸提时间为2 h,在此条件下,红菇多糖得率达到6.28%.     

正交试验法提取黄芪多糖工艺研究

以黄芪多糖粗提物综合评价,利用L9(34)正交实验从水提醇沉法中优选黄芪多糖最佳提取工艺条件,为黄芪多糖的开发利用提供实验基础。最佳工艺条件为:100℃、4 h、140 mL/10克、pH(8),醇沉以无水、三倍量最佳。     

凤尾草多糖两种测定方法的比较

目的:为选出一种比较准确、方便测定凤尾草多糖的方法。方法:通过热浸法提取凤尾草中多糖,采用蒽酮-硫酸法、苯酚-硫酸法两种方法进行含量测定比较。结果:蒽酮-硫酸法和苯酚-硫酸法的稳定性实验RSD分别为1.56%和0.68%,精密度实验RSD分别为9.35%和2.28%,回收率平均值分别91.71%和99.23%。结论:苯酚-硫酸法具有稳定性好、精密度高,而且回收率实验也较为理想,是测定凤尾草多糖含量较为理想的方法。     

麦冬多糖提取工艺的研究

以麦冬总多糖百分含量为指标,采用正交设计对用热水浸提醇沉法提取麦冬多糖的工艺条件进行了优选研究。在提取过程中,根据单因素实验确定了醇沉时乙醇的用量为浓缩液体积的5倍,含量测定时的最佳显色时间为15min;设计L9(33)正交实验,利用苯酚-硫酸法进行含量测定,重点考察加水量、提取温度和提取次数对提取效果的影响。结果显示提取麦冬多糖的优选工艺条件为加12倍量水,70℃水浴,提取3次,总多糖含量为67.83%。     

正交试验优化芒果叶多糖的提取工艺

对利用超声波辅助法提取芒果叶多糖的最佳工艺进行研究,结果表明,芒果叶多糖的最佳提取条件为:料液比1∶50、超声波温度50℃、超声波功率400 W、超声波时间20 min、3.5倍体积的95%乙醇进行沉淀,以此条件提取的多糖含量为9.979mg/g.     

正交试验法研究藏药鬼箭锦鸡儿总黄酮含量

采用正交试验设计，以总黄酮含量为考察指标，研究鬼箭锦鸡儿总黄酮最佳提取方法。采用分光光度法，以芦丁为对照物，测定总黄酮含量。结果显示，藏药鬼箭锦鸡儿总黄酮平均含量5．32％(RSD=1．52％，n=5)。     

Improvement of xylanase production by Aspergillus niger XY-1 using response surface methodology for optimizing the medium composition

Objective: To study the optimal medium composition for xylanase production by Aspergillus niger XY-1 in solid-state fermentation (SSF). Methods: Statistical methodology including the Plackett-Burman design (PBD) and the central composite design (CCD) was employed to investigate the individual crucial component of the medium that significantly affected the enzyme yield. Results: Firstly, NaNO3, yeast extract, urea, Na2CO3, MgSO4, peptone and (NH4)2SO4 were screened as the significant factors positively affecting the xylanase production by PBD. Secondly, by valuating the nitrogen sources effect, urea was proved to be the most effective and economic nitrogen source for xylanase production and used for further optimization.Finally, the CCD and response surface methodology (RSM) were applied to determine the optimal concentration of each sig-nificant variable, which included urea, Na2CO3 and MgSO4. Subsequently a second-order polynomial was determined by mul-tiple regression analysis. The optimum values of the critical components for maximum xylanase production were obtained as follows: x1 (urea)=0.163 (41.63 g/L), x2 (Na2CO3)=-1.68 (2.64 g/L), x3 (MGSO4)=1.338 (10.68 g/L) and the predicted xylanase value was 14374.6 U/g dry substrate. Using the optimized condition, xylanase production by Aspergillus niger XY-1 after 48 h fermentation reached 14637 U/g dry substrate with wheat bran in the shake flask. Conclusion: By using PBD and CCD, we obtained the optimal composition for xylanase production by Aspergillus niger XY-1 in SSF, and the results of no additional expensive medium and shortened fermentation time for higher xylanase production show the potential for industrial utilization.     

Improved elastase production by Bacillus sp.EL31410--further optimization and kinetics studies of culture medium for batch fermentation

An efficient culture medium producing a bacterial elastase with high yields was developed further following preliminary studies by means of response surface method. Central composite design (CCD) and response surface methodology were applied to optimize the medium constituents. A central composite design was used to explain the combined effect of three medium constituents, viz, glucose, K2HPO4, MgSO4@7H2O. The strain produced more elastase in the completely optimized medium, as compared with the partially optimized medium. The fitted model of the second model, as per RSM,showed that glucose was 7.4 g/100 ml, casein 1.13 g/100 ml, corn steep flour 0.616 g/100 ml, K2HPO4 0.206 g/100 ml and MgSO4@7H2O 0.034 g/100 ml. The fermentation kinetics of these two culture media in the flask experiments were analyzed. It was found that the highest elastase productivity occurred at 54 hours. Higher glucose concentration had inhibitory effect on elastase production. At the same time, we observed that the glucose consumption rate was slow in the completely optimized medium, which can explain the lag period of the highest elastase production. Some metal ions and surfactant additives also affected elastase production and cell growth.     

Improved elastase production by Bacillus sp. EL31410─further optimization and kinetics studies of culture medium for batch fermentation

INTRODUCTION Elastase is an enzyme that attacks and solubi-lizes elastin. As elastase can degrade elastin (Mori-hara, 1967) that other proteases cannot; it has broad applications in medical therapy, food processing and daily use chemicals industry. Considerable eff- orts were made to screen the elastase-producing strains, to study its pathogen effect and its charac-terizations (Tsuzuki and Oka, 1965; Tsai et al., 1988; Sharon et al., 1997; Ozaki and Shiio, 1975). Shiio, 1975). Reporte…     

Influence of medium components on elastase production using crude sources by Bacillus sp. EL31410

A newly isolated strain EL31410, producing elastase (E.C3.4.4.7) with high elastolytic activity was identified as Bacillus sp. In the medium optimization, it was found that wheat bran and soybean flour hydrosate were the best crude carbon and nitrogen source for enzyme production, respectively. Addition of corn steep flour can affect the bacterium growth and elastase production. A fractional factorial design was applied to study the main factors that affect the enzyme production, and central composite experimental design and response surface methodology were adopted to derive a statistical model for the effect of wheat bran and soybean flour hydrosate on elastase production. The experimental results showed that wheat bran had positive effect but soybean flour hydrosate had negative effect, on enzyme production. An initial concentration of 3.4%(w/v) wheat bran and 9.4%(v/v) soybean flour hydrosate were found to be optimal for enzyme production in batch culture. The time course of elastase production in the optimized medium composition was also described.     

Influence of medium components on elastase production using crudesources by Bacillus sp. EL31410

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Improved elastase production by<Emphasis Type="Italic">Bacillus</Emphasis> sp. EL31410 —Further optimization and kinetics studies of culture medium for batch fermentation

An efficient culture medium producing a bacterial elastase with high yields was developed further following preliminary studies by means of response surface method. Central composite design (CCD) and response surface methodology were applied to optimize the medium constituents. A central composite design was used to explain the combined effect of three medium constituents, viz, glucose, K₂HPO₄, MgSO₄·7H₂O. The strain produced more elastase in the completely optimized medium, as compared with the partially optimized medium. The fitted model of the second model, as per RSM, showed that glucose was 7.4 g/100 ml, casein 1.13 g/100 ml, corn steep flour 0.616 g/100 ml, K₂HPO₄ 0.206 g/100 ml and MgSO₄·7H₂O 0.034 g/100 ml. The fermentation kinetics of these two culture media in the flask experiments were analyzed. It was found that the highest elastase productivity occurred at 54 hours. Higher glucose concentration had inhibitory effect on elastase production. At the same time, we observed that the glucose consumption rate was slow in the completely optimized medium, which can explain the lag period of the highest elastase production. Some metal ions and surfactant additives also affected elastase production and cell growth. Project (No. 300024) supported by the Natural Science Foundation of Zhejiang Province, China     

Influence of medium components on elastase production using crude sources by<Emphasis Type="Italic">Bacillus</Emphasis> sp. EL31410

A newly isolated strain EL31410, producing elastase (E. C3. 4. 4. 7) with high elastolytic activity was identified asBacillus sp. In the medium optimization, it was found that wheat bran and soybean flour hydrosate were the best crude carbon and nitrogen source for enzyme production, respectively. Addition of corn steep flour can affect the bacterium growth and elastase production. A fractional factorial design was applied to study the main factors that affect the enzyme production, and central composite experimental design and response surface methodology were adopted to derive a statistical model for the effect of wheat bran and soybean flour hydrosate on elastase production. The experimental results showed that wheat bran had positive effect but soybean flour hydrosate had negative effect, on enzyme production. An initial concentration of 3.4% (w/v) wheat bran and 9.4% (v/v) soybean flour hydrosate were found to be optimal for enzyme production in batch culture. The time course of elastase production in the optimized medium composition was also described. Project (No. 300024) supported by the Zhejiang Provincial Natural Science Foundation of China