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1.
Lipid extraction from biological samples is a critical and often tedious preanalytical step in lipid research. Primarily on the basis of automation criteria, we have developed the BUME method, a novel chloroform-free total lipid extraction method for blood plasma compatible with standard 96-well robots. In only 60 min, 96 samples can be automatically extracted with lipid profiles of commonly analyzed lipid classes almost identically and with absolute recoveries similar or better to what is obtained using the chloroform-based reference method. Lipid recoveries were linear from 10-100 μl plasma for all investigated lipids using the developed extraction protocol. The BUME protocol includes an initial one-phase extraction of plasma into 300 μl butanol:methanol (BUME) mixture (3:1) followed by two-phase extraction into 300 μl heptane:ethyl acetate (3:1) using 300 μl 1% acetic acid as buffer. The lipids investigated included the most abundant plasma lipid classes (e.g., cholesterol ester, free cholesterol, triacylglycerol, phosphatidylcholine, and sphingomyelin) as well as less abundant but biologically important lipid classes, including ceramide, diacylglycerol, and lyso-phospholipids. This novel method has been successfully implemented in our laboratory and is now used daily. We conclude that the fully automated, high-throughput BUME method can replace chloroform-based methods, saving both human and environmental resources.  相似文献   
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Nonexhaustive extraction (propanol, butanol, hydroxypropyl-β-cyclodextrin [HPCD]), persulfate oxidation and biodegradability assays were employed to determine the bioavailability of polycyclic aromatic hydrocarbons (PAHs) in creosote-contaminated soil. After 16 weeks incubation, greater than 89% of three-ring compounds (acenaphthene, anthracene, fluorene, and phenanthrene) and 21% to 79% of four-ring compounds (benz[a]anthracene, chrysene, fluoranthene, and pyrene) were degraded by the indigenous microorganisms under biopile conditions. No significant decrease in five- (benzo[a]pyrene, benzo[b+k]fluoranthene) and six-ring compounds (benz[g,h,i]perylene, indeno[1,2,3-c,d]pyrene) was observed. Desorption of PAHs using propanol or butanol could not predict PAH biodegradability: low-molecular-weight PAH biodegradability was underestimated whereas high-molecular-weight PAH biodegradability was overestimated. Persulfate oxidation and HPCD extraction of creosote-contaminated soil was able to predict three- and four-ring PAH biodegradability; however, the biodegradability of five-ring PAHs was overestimated. These results demonstrate that persulfate oxidation and HPCD extraction are good predictors of PAH biodegradability for compounds with octanol-water partitioning coefficients of < 6.  相似文献   
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研究在培养基中加入不同电子载体对丁醇发酵的影响。结果表明:添加微量的苄基紫精可以促进丁醇的产生,同时可强烈抑制丙酮的合成,丁醇体积分数由66.92%提高到82.35%。苄基紫精可促进菌株快速进入产溶剂期,发酵周期明显缩短,丁醇生产强度显著提高。7%玉米培养基中加入40 mg/L苄基紫精,丁醇产量最高达16.10 g/L,生产强度为0.37 g/(L.h),分别较对照提高10.96%和60.87%。在初始丁醇体积分数较低的条件下,苄基紫精对丁醇合成的促进作用更明显。  相似文献   
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纤维素丁醇作为一种新型可再生能源,具有与汽油配伍性好、蒸汽压较低、安全系数高、能量密度高及抗爆性好等优势,在替代化石燃料方面极具发展前景,已受到广泛关注。虽然纤维素丁醇工业化生产仍存在一定的技术瓶颈,生产技术经济性也较差,产业化发展受到限制,但未来通过政策支持,在丰富的农林剩余物资源及巨大市场需求的条件下,纤维素丁醇作为新型能源仍具有非常广阔的发展前景。为了更好地促进纤维素丁醇产业发展,以纤维素丁醇的产业化发展为研究对象,总结了纤维素丁醇产业发展现状,分析了纤维素丁醇产业发展过程中存在的问题,从政策、资源及市场等方面对未来纤维素丁醇产业发展的前景进行了预测,并对如何促进其产业化发展提出了建议。  相似文献   
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Continuous butanol/isopropanol fermentation with immobilized Clostridium isopropylicum was performed in a downflow column reactor using molasses as the substrate. In order to prevent product inhibition and at the same time obtain high concentration of the products, the column reactor was coupled with a pervaporation module using a supported liquid membrane. The liquid membrane was prepared with oleyl alcohol nontoxic to the microorganism. In comparison with the continuous fermentation without product removal, the specific butanol production rate was 2 times higher. The butanol concentration in the permeate was 230 kg/m(3), which was about 50 times higher than that in the culture broth. A numerical investigation suggested a further increase in the productivity by improving the module construction.  相似文献   
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Studies on the lipozyme-catalyzed synthesis of butyl laurate   总被引:4,自引:0,他引:4  
The effects of temperature, speed of agitation, enzyme concentration, etc., on butyl laurate synthessis using Mucor miehei lipase (Lipozymetrade mark) have been studied. Although the soluble enzyme was quite thermcstable in aqeous solution, it deactivated rapidly at and above 40 degrees C in the presence of butanol. This enzyme immobilized on an anion-exchange resin (Lipozymetrade mark) showed enhanced stability (as compared to the soluble form) to denaturation by butanol under the same conditions. The denaturation of M. miehei lipase was found to be a function of the butanol concentration in the aqueous phase, and rapid denaturation takes place at the concentration corresponding to its saturation at that temperature. (c) 1995 John Wiley & Sons, Inc.  相似文献   
8.
A novel acetone-butanol production process was developed which integrates a repeated fed-batch fermentation with continuous product removal and cell recycle. The inhibitory product concentrations of the fermentation by Clostridium acetobutylicum were reduced by the simultaneous extraction process using polyvinylpyridine (PVP) as an adsorbent. Because of the reduced inhibition effect, a higher specific cell growth rate and thus a higher product formation rate was achieved. The cell recycle using membrane separation increased the total cell mass density and, therefore, enhanced the reactor productivity. The repeated fed-batchoperation overcame the drawbacks typically associated with a batch operation such as down times, long lag period, and the limitation on the maximum initial substrate concentration allowed due to the substrate inhibition. Unlike a continuous operation, the repeated fed-batch operation could beoperated for a long time at a relatively higher substrate concentration without sacrificing the substrate loss in the effluent. As a result, the integrated process reached 47.2 g/L in the equivalent solvent concentration (including acetone, butanol, and ethanol) and 1.69 g/L . h in the fermentor productivity, on average, over a 239.5-h period. Compared with a controlled traditional batch acetone-butanol fermentation, the equivalent solvent concentration and the tormentor productivity were increased by 140% and 320%, respectively. (c) 1995 John Wiley & Sons Inc.  相似文献   
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生物柴油耦联丙酮丁醇发酵的初步研究   总被引:10,自引:0,他引:10  
以4种生物柴油(原料为地沟油、菜籽油、棕榈油和废肯德基油)作为萃取剂,开展了丙酮丁醇静态萃取发酵。通过分析发酵过程中的产气量及发酵40 h后油水两相中的溶剂浓度,发现生物柴油对丙丁梭菌有毒性。另外,静置条件下丁醇在不同油水两相中的液液平衡系数大致相同。在发酵24 h时加入棕榈生物柴油(油水体积比为0.4∶1),丁醇发酵强度达到最大值0.213 g.(L.h)-1、比对照(传统发酵)提高10.9%,且生物柴油中的丁醇质量浓度达到6.44 g.L-1。  相似文献   
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