Optimization of Bacillus subtilis cell growth effecting jiean-peptide production in fed batch fermentation using central composite design

BackgroundOptimization of nutrient feeding was developed to improve the growth of Bacillus subtilis in fed batch fermentation to increase the production of jiean-peptide (JAA). A central composite design (CCD) was used to obtain a model describing the relationship between glucose, total nitrogen, and the maximum cell dry weight in the culture broth with fed batch fermentation in a 5 L fermentor.ResultsThe results were analyzed using response surface methodology (RSM), and the optimized values of glucose and total nitrogen concentration were 30.70 g/L and 1.68 g/L in the culture, respectively. The highest cell dry weight was improved to 77.50 g/L in fed batch fermentation, which is 280% higher than the batch fermentation concentration (20.37 g/L). This led to a 44% increase of JAA production in fed batch fermentation as compared to the production of batch fermentation.ConclusionThe results of this work improve the present production of JAA and may be adopted for other objective products' production.     

广西发展填充母料现状及优势分析

文章综述了全国母料行业市场现状、产业现状、标准化现状及发展前景,浅谈广西母料行业发展现状,并在分析全国母料行业发展现状的基础上,提出广西应重点发展填充母料,并分析广西发展填充母料的优势。     

Improvement of ethanol production from sweet sorghum juice under batch and fed-batch fermentations: Effects of sugar levels,nitrogen supplementation,and feeding regimes

BackgroundFermentation process development has been very important for efficient ethanol production. Improvement of ethanol production efficiency from sweet sorghum juice (SSJ) under normal gravity (NG, 160 g/L of sugar), high gravity (HG, 200 and 240 g/L of sugar) and very high gravity (VHG, 280 and 320 g/L of sugar) conditions by nutrient supplementation and alternative feeding regimes (batch and fed-batch systems) was investigated using a highly ethanol-tolerant strain, Saccharomyces cerevisiae NP01.ResultsIn the batch fermentations without yeast extract, HG fermentation at 200 g/L of sugar showed the highest ethanol concentration (P_E, 90.0 g/L) and ethanol productivity (Q_E, 1.25 g/L·h). With yeast extract supplementation (9 g/L), the ethanol production efficiency increased at all sugar concentrations. The highest P_E (112.5 g/L) and Q_E (1.56 g/L·h) were observed with the VHG fermentation at 280 g/L of sugar. In the fed-batch fermentations, two feeding regimes, i.e., stepwise and continuous feedings, were studied at sugar concentrations of 280 g/L. Continuous feeding gave better results with the highest P_E and Q_E of 112.9 g/L and 2.35 g/L·h, respectively, at a feeding time of 9 h and feeding rate of 40 g sugar/h.ConclusionsIn the batch fermentation, nitrogen supplementation resulted in 4 to 32 g/L increases in ethanol production, depending on the initial sugar level in the SSJ. Under the VHG condition, with sufficient nitrogen, the fed-batch fermentation with continuous feeding resulted in a similar P_E and increased Q_P by 51% compared to those in the batch fermentation.     

研究生学位信息电子照片批量处理小程序

学位信息年报时需要对电子照片进行处理以符合上报要求,这里介绍一款基于Vb2005的小程序,能够实现照片的批量处理。     

一种基于Oracle的数据存储优化方法

介绍了Oracle的应用程序接口OCI,分析了SQL的执行过程。针对常规数据存储方法在海量数据存储和系统并发用户较多时效率低下的问题,定义一种简洁的数据结构,创建存储过程并完成对SQL信息的压缩。对比优化前后的实验数据,可以发现此方法能显著提高Oracle的数据存储效率。     

多品种小批量的多车配载模型研究

货物配载是专业第三方物流中心货物运输的关键环节,为取得最优装配方案,在容重比平衡的基础上综合了客户讨价还价能力、调车成本、送达时间等更多的因素建立相应的优化模型旨在降低运输成本提高物流中心的经济效益,从而对于物流中心的实际配载问题优化具有一定的借鉴和参考作用。     

Activism, drug regulation, and the politics of therapeutic evaluation in the AIDS era: a case study of ddC and the 'surrogate markers' debate

This paper presents an extended case study to demonstrate that the interpretation of clinical trials of antiviral AIDS drugs is significantly shaped by a widely dispersed allocation of scientific credibility. Specifically, the participation of AIDS activists in claims-making about AIDS trials and AIDS drugs complicates the politics of therapeutic evaluation, even as it challenges the monopolization of credibility by credentialed researchers. The paper tracks the social construction of belief about the efficacy of the combination therapy of AZT and ddC, between 1990 and 1995 in the United States. By intervening simultaneously in interpretative debates about the results of the clinical trials of this therapy and in methodological debates about how efficacy might best be measured in such trials, activists have helped to shape what is believed to be known about these drugs.     

复方新诺明在艾滋病合并卡氏肺孢子虫肺炎中的应用

艾滋病作为一种传染性疾病,正以惊人的速度在全球蔓延。这种疾病不仅是当今世界上最大的公共卫生问题之一,也是一个社会、经济问题。艾滋病具有传播迅速、发病缓慢、病死率高的特点,机会性感染是艾滋病最主要的死亡原因,复方新诺明治疗和预防艾滋病合并卡氏肺孢子虫肺炎具有良好效果。     

美NIAID所长:人类已有遏制艾滋病疫情工具

艾滋病在全球肆虐30余年来,夺去约3000万人的生命,造成严重的经济、社会负担,世界各国与这一共同敌人展开激烈的持久战。美国国家过敏和传染病研究所(NIAID)所长安东尼.福奇认为,在这场战争中,人类已拥有遏制艾滋病疫情的工具,但真正控制住这一疫情尚需时     

适宜广西产业扶贫的5种特色中药材种植关键技术

广西药用植物资源在全国位居前列,药材产量在全国具有重要影响.目前,中药材种植已在广西形成了不同规模的县市级集约产区及产业结构体系,并成为50多个贫困县的扶贫支柱产业.选择适合区域发展的特色中药材品种,了解生产种植关键技术是实现中药材高产和产业扶贫的根本保障.文章从繁育技术和栽培技术两个主要方面系统介绍了五指毛桃、皇菊等...     

SBR亚硝化处理化肥厂氨氮废水影响因素分析

利用SBR亚硝化处理化肥厂实际废水,研究其短程生物脱氮过程中pH、溶解氧、进水氨氮负荷和温度等因素影响,并确定亚硝化处理的最佳操作条件。结果表明,pH过低会抑制亚硝酸盐的生成,过高则不利于反硝化菌反硝化过程TN的去除;当pH值控制在8.0左右时,亚硝化率保持较高水平,同时出水TN浓度控制较好。当DO浓度为0.2~0.3 mg/L时,亚硝化反应继续进行,但NH4+-N亚硝化反应速率较慢;当DO浓度为1.5~2.8 mg/l时,无法实现系统中亚硝化的运行,硝化作用成为主要反应。高氨氮负荷进水有利于亚硝酸盐的积累,但对出水氨氮去除效果不佳。较高的温度有利于亚硝化反应进行。当t=35℃,初始pH控制在7.8~8.2,DO控制在0.5~0.6mg/L,进水浓度NH4+-N为100mg/L时,SBR亚硝化操作过程为最佳,此时亚硝化率基本稳定在90%以上。     

Photocatalysis in solar fuel production

<正>With the increasing concerns on energy and environmental problems caused by the combustion of fossil fuels,solar energy becomes vitally important because it is the only viable renewable energy source that can replace the fossil fuels in     

中华跌打丸及其药材鬼画符提取物的抗炎作用评价

目的:评价中华跌打丸及其药材鬼画符提取物的抗炎作用.方法:本研究采用硫酸铜诱导建立转基因中性粒细胞荧光斑马鱼炎症模型,系统评价中华跌打丸和鬼画符各浓度提取物的抗炎作用.结果:与正常对照组比较,模型对照组斑马鱼炎症部位中性粒细胞数显著增加.与模型对照组比较,中华跌打丸给药浓度为222 μg/mL、667 μg/mL和20...     

创新中药材专业市场质量监管模式的实证研究

在对成都市荷花池中药材市场现状调查分析的基础上,对创新中药材专业市场的质量监管模式进行了探索与研究,以有效保证与提高药材质量水平.     

HIV/AIDS患者肠道菌群变化研究

艾滋病是严重危害人类健康和生命的重大疾病,艾滋病病毒感染会破坏人体肠道黏膜屏障,打破肠道菌群的平衡.文章对比HIV感染者与正常人肠道菌群之间的区别,为临床诊疗提供参考依据,进而为寻求机制学说提供科研思路.