1,3-Propanediol production from crude glycerol by Clostridium butyricum DSP1 in repeated batch

BackgroundThe production of biofuels from renewable energy sources is one of the most important issues in industrial biotechnology today. The process is known to generate various by-products, for example crude glycerol, which is obtained in the making of biodiesel from rapeseed oil. Crude glycerol may be utilized in many ways, including microbial conversion to 1,3-propanediol (1,3-PD), a raw material for the synthesis of polyesters and polyurethanes.ResultsThe paper presents results of a study on the synthesis of 1,3-propanediol from crude glycerol by a repeated batch method with the use of Clostridium butyricum DSP1. Three cycles of fermentation medium replacement were carried out. The final concentration of 1,3-PD was 62 g/L and the maximum productivity, obtained during the second cycle, reached 1.68 g/L/h. Additionally, experiments conducted in parallel to the above involved using the entire quantity of the culture broth removed from the bioreactor to inoculate successive portions of fermentation media containing crude glycerol at concentrations of 80 g/L and 100 g/L. Under those conditions, the maximum 1,3-PD concentrations were 43.2 g/L and 54.2 g/L.ConclusionsThe experiments proved that by using a portion of metabolically active biomass as inoculum for another fermentation formula it is possible to eliminate the stage of inoculum growth and thereby reduce the length of the whole operation. Additionally, that strategy avoids the phase of microbial adaptation to a different source of carbon such as crude glycerol, which is more difficult to utilize, thus improving the kinetic parameters of 1,3-PD production.     

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.     

基于长尾理论的创客运动多品种小批量生产模式分析

创客运动是创新活动趋向大众化的新兴现象。从长尾理论的角度,对创客运动的多品种小批量生产模式进行分析,研究其在生产主体、盈利空间以及融资方式的创新之处,并针对其存在的问题提出相应的建议。     

Lead Poisoning Due to Herbal Medications

Lead ranks as one of the most serious environmental poisons all over the world amongst toxic heavy metals with no known biological function useful for the human body. A case of lead toxicity due to consumption of herbal medicine is being discussed. The case presented with gastrointestinal complaints and history of intake of herbal medicines for diabetes control for past 8 months. The analysis of the powdered herbal medicine procured from ayurveda practitioner was found to have high content of lead responsible for the lead toxicity. The patient is under regular followup. He has improved symptomatically on chelating therapy and blood lead levels have gradually improved. Regular awareness programs should be conducted in the population regarding possible exposure through home made herbal remedies so that general public can be made aware of the dangerous side effects of lead and other heavy metals on health.     

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。     

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.     

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。     

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。     

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     

中国科学院首批资深院士名单

根据国务院决定和《中国科学院院士章程》的规定,从１９９８年７月１日起,在中国科学院院士中实行资深院士制度,对年满８０周岁的中国科学院院士,授予“中国科学院资深院士”称号。首批资深院士名单如下：（１４５人,按姓氏笔画排序）数学物理学部：１９人马大猷王淦昌严志达何泽慧应崇福李正武汪德昭沈元苏步青柯召段学复谈镐生钱伟长钱学森钱临照彭桓武程民德葛庭燧魏荣爵化学部：２４人冯新德卢嘉锡申泮文邢其毅严东生吴征铠吴浩青张滂张青莲时钧汪德熙肖伦陈冠荣侯祥麟唐敖庆钱人元高鸿高济宇梁树权黄耀曾嵇汝运彭少逸蔡启瑞戴安邦…     

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...