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1.
Paprika powder, naturally contaminated with aflatoxins, was extracted by supercritical carbon dioxide at standard conditions (300 bar and 50 degrees C). A lipophilic top phase and an aqueous base phase were obtained. These and the extraction residue were analysed by HPLC for aflatoxins. The main quantity of aflatoxins, about 60% of aflatoxin B1 and about 70% of aflatoxin B2 related to the original paprika powder, was found to be located in the extraction residue. This confirms the results of previous studies with other spices and demonstrates that the use for flavouring purposes of supercritical carbon dioxide extracts, rather than natural spice, offers potential application in reducing aflatoxin levels in spiced foods. 相似文献
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We investigated a novel method for the selective separation of beta-carotene isomers from a freeze-dried powder of the algae Dunaliella bardawil using supercritical fluid extraction. The separation method relies on the different dissolution rate of the 9Z and all-E isomers of beta-carotene in SC-CO(2). At first, the equilibrium solubility of the two isomers in SC-CO(2) was determined at the extraction conditions of 44.8 MPa and 40 degrees C. The solubility of the 9Z isomer was found to be nearly 4 times higher than that of the all-E isomer (1.92 x 10(-5) g all-E isomer/g CO(2) compared to 7.64 x 10(-5) g 9Z isomer/g CO(2)). When supercritical fluid extraction was applied to a carotenoid concentrate from the algae (29 wt% beta-carotene) or a freeze-dried powder of the algae (3.1% beta-carotene), a selective separation of the 9Z/all-E isomers of beta-carotene was obtained. Thirty-nine percent recovery of beta-carotene with 80% purity of 9Z isomer was achieved at the initial stages of extraction (40 mL CO(2)). The extraction rate of beta-carotene from the freeze-dried algae powder was slower than that from the carotenoid concentrate, resulting in a reduction in the recovery and purity of the 9Z isomer. This indicates that even at the initial stage of the extraction the internal mass resistance is significant. Isomer purity and recovery could be enhanced upon grinding of the algae powder. 相似文献
4.
The topological structure of plasmid DNA can be characterized by capillary gel electrophoresis (CGE analysis)-an important tool for quality control and stability assessments in DNA storage or application. Hence, a large-scale manufacturing process was developed that allows the removal of undesired open circular (oc) or linear plasmid topologies, bacterial genomic DNA, RNA, proteins as well as lipopolysaccharides (endotoxins) and results in obtaining supercoiled (covalently closed circular, ccc) plasmid DNA in a pure form without using any animal-derived substances. Using CGE, the development and in-line monitoring for pharmaceutical plasmid production starting from fermentation control throughout the whole manufacturing process including the formulated and filled product can be performed the first time in a way conforming to good manufacturing practices (GMP). Plasmid stability data were obtained from analysis of shear effects influencing the plasmid quality in DNA drug delivery formulation and application (e.g. gene gun or jet injection). The physical stability of plasmid DNA is for the first time evaluated in DNA storage experiments on the level of different plasmid forms. 相似文献
5.
Dimethyl carbonate as potential reactant in non-catalytic biodiesel production by supercritical method 总被引:2,自引:0,他引:2
In this study, the non-catalytic supercritical method has been studied in utilizing dimethyl carbonate. It was demonstrated that, the supercritical dimethyl carbonate process without any catalysts applied, converted triglycerides to fatty acid methyl esters with glycerol carbonate and citramalic acid as by-products, while free fatty acids were converted to fatty acid methyl esters with glyoxal. After 12 min of reaction at 350 degrees C/20 MPa, rapeseed oil treated with supercritical dimethyl carbonate reached 94% (w/w) yield of fatty acid methyl ester. The by-products from this process which are glycerol carbonate and citramalic acid are much higher in value than glycerol produced by the conventional process. In addition, the yield of the fatty acid methyl esters as biodiesel was almost at par with supercritical methanol method. Therefore, supercritical dimethyl carbonate process can be a good candidate as an alternative biodiesel production process. 相似文献
6.
为了探讨超临界二氧化碳(supercritical carbon dioxide, SC-CO2)技术与提取物的分级分离在萃取芸香活性成分的应用价值,本研究采用SC-CO2和乙酸乙酯萃取芸香中植物蜡和活性成分,并调查粒径和CO2流量对提取产量的影响。在250 bar、40℃条件下提取,并使第一个分离器冷却到-10℃,可获得较好的提取效率。当粒径较小时,提取过程更快,即内部传质控制该过程。分级分离可选择性去除表皮植物蜡,约占由SC-CO2处理产生的总提取物的77.5%W/W。第二分离器中的获得的提取物中活性化合物可达86.3%W/W。随后采用气相色谱-质谱联用仪(gas chromatography-mass spectrometry, GC-MS)分析表明,乙酸乙酯提取物低于SC-CO2提取物的萃取效率,主要是由于提取物中含有大量的植物蜡。本研究为超临界二氧化碳技术在萃取芸香活性成分方面的提供技术参考。 相似文献
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本文综述了在海洋资源开发上应用的现代生物工程分离技术。介绍了最新的分离提取技术如制备型和生产型色谱技术、超临界萃取技术、膜分离技术、毛细管电泳技术、酶工程技术等。从海洋生物资源中提取有用的生物活性物质,需要符合特定要求的现代生物工程技术。其中柱层析技术和超临界萃取技术是海洋生物活性物质分离提取技术中的主要部分。 相似文献
8.
Formation of inhalable microparticles containing rifampicin and poly(l-lactide) (L-PLA) by using supercritical anti-solvent process (SAS) was investigated. The solutions of drug and polymer in
methylene chloride were sprayed into supercritical carbon dioxide. The effect of polymer content and operating conditions,
temperature, pressure, carbon dioxide molar fraction, and concentration of solution, on product characteristics were studied.
The prepared microparticles were characterized with respect to their morphology, particle size and size distribution, drug
content, drug loading efficiency, and drug release characteristic. Discrete, spherical microparticles were obtained at high
polymer:drug ratios of 7:3, 8:2, and 9:1. The shape of L-PLA microparticles became more irregular and agglomerated with decreasing
polymer content. Microparticles with polymer content higher than 60% exhibited volumetric mean diameter less than 5 μm, but
percent drug loading efficiency was relatively low. Drug-loaded microparticles containing 70% and 80% L-PLA showed a sustainable
drug release property without initial burst release. Operating temperature level influenced on mean size and size distribution
of microparticles. The operating pressure and carbon dioxide molar fraction in the range investigated were unlikely to have
an effect on microparticle formation. An increasing concentration of feed solution provided larger size microparticles. Rifampicin-loaded
L-PLA microparticles could be produced by SAS in a size range suitable for dry powder inhaler formulation. 相似文献
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Baig MN Santos RC Zetzl C King J Pioch D Bowra S 《Enzyme and microbial technology》2011,49(4):420-426
Supercritical fluids offer environmental advantages over chemical solvents, while providing enhanced separation and chemical selectivity. The use of supercritical fluids for the recovery of products from biomass and the transformation of selected molecules (to add value) was studied. Free fatty acids were bio-catalytically transformed to fatty acid esters using lipase within a supercritical fluid environment. A central composite rotatable design was used to evaluate the influence of operating conditions on the enzymatic esterification process and a response surface equation was optimized to identify the most favourable process conditions for maximum free fatty acid conversion. Based on the model equation the process conditions under which it was predicted a yield of 100% esters could be obtained were: pressure 200 bar, temperature 60 °C, ethanol concentration 2.0 M, enzyme concentration 11 wt.% and time 60 min. Experiments conducted under these conditions gave an ester yield of 94.3% (close to predicted results). The activity per unit mass of biocatalyst was found to be 1585 μmol/min/gcat. The results support the use of supercritical fluids for process integration. 相似文献
11.
A study was carried out on the application of supercritical fluid to the hydrolysis of boll fibers of cotton (cultivar Tashkent-6
ofGossypium hirsutum L.) by cellulase enzymes fromTrichoderma viride, Trichoderma reesei andAspergillus niger. Conditions of the enzymatic process were optimized. The stabilities of cellulase enzymes were sustained, at the pressure
of up to 160 atm for 48 hours at 50°C in supercritical carbon dioxide. 相似文献
12.
Chunsheng H Qinglin Z Yuxin L Xiaochen C Yanliang W Tong Z Zuze W 《Biotechnology and applied biochemistry》2011,58(3):162-165
Plasmid DNA for biopharmaceutical applications is produced easily in Escherichia coli bacteria. The cell lysis is the most crucial step for purification of plasmid DNA. In this paper, we describe a continuous cell alkaline lysis, neutralization, and clarification combination process for production of plasmid pUDK-HGF using hollow fiber ultrafiltration column as a lysis chamber and compare the plasmid DNA yield and homogeneity with the T-connector and manual processes, respectively. The results show that the plasmid pUDK-HGF yield of the combination process is 13% higher than manual lysis, twice higher than using T-connector. When the proportion of lysed cells and neutralization solution is 3:1, the plasmid pUDK-HGF yield can improve by 70%. This process could be easily scaled up to meet the industrial scale for cell lysis. 相似文献
13.
Melissa L. Mather Michael Brion Lisa J. White Kevin M. Shakesheff Steven M. Howdle Stephen P. Morgan John A. Crowe 《Biotechnology progress》2009,25(4):1176-1183
This article demonstrates the application of time‐lapsed imaging and image processing to inform the supercritical processing of tissue scaffolds that are integral to many regenerative therapies. The methodology presented provides online quantitative evaluation of the complex process of scaffold formation in supercritical environments. The capabilities of the developed system are demonstrated through comparison of scaffolds formed from polymers with different molecular weight and with different venting times. Visual monitoring of scaffold fabrication enabled key events in the supercritical processing of the scaffolds to be identified including the onset of polymer plasticization, supercritical points and foam formation. Image processing of images acquired during the foaming process enabled quantitative tracking of the growing scaffold boundary that provided new insight into the nature of scaffold foaming. Further, this quantitative approach assisted in the comparison of different scaffold fabrication protocols. Observed differences in scaffold formation were found to persist, post‐fabrication as evidenced by micro x‐ray computed tomography (μ x‐ray CT) images. It is concluded that time‐lapsed imaging in combination with image processing is a convenient and powerful tool to provide insight into the scaffold fabrication process. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 相似文献
14.
The purpose of this research was to micronize beclomethasone-17,21-dipropionate (BDP), an anti-inflammatory inhaled corticosteroid
commonly used to treat asthma, using the rapid expansion of supercritical solution (RESS) technique. The RESS technique was
chosen for its ability to produce both micron particles of high purity for inhalation, and submicron/nano particles as a powder
handling aid for use in next generation dry powder inhalers (DPIs). Particle formation experiments were carried out with a
capillary RESS system to determine the effect of experimental conditions on the particle size distribution (PSD). The results
indicated that the RESS process conditions strongly influenced the particle size and morphology; with the BDP mean particle
size decreasing to sub-micron and nanometer dimensions. An increase in the following parameters, i.e. nozzle diameter, BDP
mol fraction, system pressure, and system temperature; led to larger particle sizes. Aerodynamic diameters were estimated
from the SEM data using three separate relations, which showed that the RESS technique is promising to produce particles suitable
for pulmonary delivery. 相似文献
15.
Testing plasmid stability of Escherichia coli using the Continuously Operated Shaken BIOreactor System
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Michaela Sieben Gregor Steinhorn Carsten Müller Simone Fuchs Laura Ann Chin Lars Regestein Jochen Büchs 《Biotechnology progress》2016,32(6):1418-1425
Plasmids are common vectors to genetically manipulate Escherichia coli or other microorganisms. They are easy to use and considerable experience has accumulated on their application in heterologous protein production. However, plasmids can be lost during cell growth, if no selection pressure like, e.g., antibiotics is used, hampering the production of the desired protein and endangering the economic success of a biotechnological production process. Thus, in this study the Continuously Operated Shaken BIOreactor System (COSBIOS) is applied as a tool for fast parallel testing of strain stability and operation conditions and to evaluate measures to counter such plasmid loss. In specific, by applying various ampicillin concentrations, the lowest effective ampicillin dosage is investigated to secure plasmid stability while lowering adverse ecological effects. A significant difference was found in the growth rates of plasmid‐bearing and plasmid‐free cells. The undesired plasmid‐free cells grew 30% faster than the desired plasmid‐bearing cells. During the testing of plasmid stability without antibiotics, the population fraction of plasmid‐bearing cells rapidly decreased in continuous culture to zero within the first 48 h. An initial single dosage of ampicillin did not prevent plasmid loss. By contrast, a continuous application of a low dosage of 10 µg/mL ampicillin in the feed medium maintained plasmid stability in the culture. Consequently, the COSBIOS is an apt reactor system for measuring plasmid stability and evaluating methods to enhance this stability. Hence, decreased production of heterologous protein can be prevented. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1418–1425, 2016 相似文献
16.
The very first application of supercritical fluid extraction (SFE) on enantioseparation of alcohols is discussed. Resolution of three chiral alcohols (trans-2-chloro-cyclohexanol, trans-2-bromo-cyclohexanol, and trans-2-iodo-cyclohexanol) were performed by partial complexation with (-)-O,O'-dibenzoyl-(2R,3R)-tartaric acid monohydrate (DBTA). DBTA formed diastereomeric complexes with all S,S-enantiomers stable enough to extract the unreacted alcohols with supercritical carbon dioxide. Resolution efficiency increased with the size of halogen substituents, and by the proper selection of molar ratio, pure (-)-R,R-trans-2-iodo-cyclohexanol (ee > 99%, yield: 39%) or (+)-S,S-trans-2-iodo-cyclohexanol (ee = 98%, yield: 8%) were prepared in one process step. Achieved resolution efficiency values were much higher in all resolution procedures than in any other known enantioseparation of these racemic compounds. The developed method offers an environmentally friendly, efficient alternative of currently applied resolution processes, also on a preparative scale. 相似文献
17.
The purpose of this study was to test the utility of rapid expansion of supercritical solution (RESS) based cocrystallizations
in inducing polymorph conversion and crystal disruption of chlorpropamide (CPD). CPD crystals were recrystallized by the RESS
process utilizing supercritical carbon dioxide as the solvent. The supercritical region investigated for solute extraction
ranged from 45 to 100°C and 2000 to 8000 psi. While pure solute recrystallization formed stage I of these studies, stage II
involved recrystallization of CPD in the presence of urea (model impurity). The composition, morphology, and crystallinity
of the particles thus produced were characterized utilizing techniques such as microscopy, thermal analysis, x-ray powder
diffractometry, and high-performance liquid chromatography. Also, comparative evaluation between RESS and evaporative crystallization
from liquid solvents was performed. RESS recrystallizations of commercially available CPD (form A) resulted in polymorph conversion
to metastable forms C and V, depending on the temperature and pressure of the recrystallizing solvent. Cocrystallization studies
revealed the formation of eutectic mixtures and solid solutions of CPD+urea. Formation of the solid solutions resulted in
the crystal disruption of CPD and subsequent amorphous conversion at urea levels higher than 40% wt/wt. Consistent with these
results were the reductions in melting point (up to 9°C) and in the ΔHfvalues of CPD (up to 50%). Scanning electron microscopy revealed a particle size reduction of up to an order of magnitude
upon RESS processing. Unlike RESS, recrystallizations from liquid organic solvents lacked the ability to affect polymorphic
conversions. Also, the incorporation of urea into the lattice of CPD was found to be inadequate. In providing the ability
to control both the particle and crystal morphologies of active pharmaceutical ingredients, RESS proved potentially advantageous
to crystal engineering. Rapid crystallization kinetics were found vital in making RESS-based doping superior to conventional
solvent-based cocrystallizations. 相似文献
18.
Triplex affinity interaction provides a new process for the purification of plasmid DNA, which is especially suited to meet the demands of a gene therapy use. We developed a method for the functionalization of a large pore affinity support suitable for this application. A 5-modified DNA oligonucleotide containing an aldehyde group was coupled to adipic acid hydrazide functionalized Sephacryl beads with a yield of 31% (over all immobilization yield 22.6% from starting oligonucleotide). The resulting selective and covalent immobilization of the ligand via a 16 atom, hydrophilic linker arm enables the oligonucleotide bases to freely bind to the target sequence. The proposed method provides affinity supports that might be used in large scale affinity purification of plasmid DNA.This revised version was published online in October 2005 with corrections to the Cover Date. 相似文献
19.
A procedure for the large-scale isolation of highly purified plasmid DNA using alkaline extraction and binding to glass powder 总被引:42,自引:0,他引:42
A preparative procedure for obtaining highly purified plasmid DNA from bacterial cells is described. The method is adapted from our earlier procedure, which gave partially purified plasmid in a form suitable for rapid screening of a large number of samples. In the present method, all detectable RNA, chromosomal DNA, and protein are removed without the use of enzymes, phenol extraction, dialysis, or equilibrium centrifugation. Binding of plasmid DNA to glass powder in the presence of 6 m sodium perchlorate is used for the final purification step. 相似文献
20.
Luca Bilancetti Denis Poncelet Catherine Loisel Stefania Mazzitelli Claudio Nastruzzi 《AAPS PharmSciTech》2010,11(3):1257-1267
This article describes the preparation of starch particles, by spray drying, for possible application to a dry powder coating
process. Dry powder coating consists of spraying a fine powder and a plasticizer on particles. The efficiency of the coating
is linked to the powder morphological and dimensional characteristics. Different experimental parameters of the spray-drying
process were analyzed, including type of solvent, starch concentration, rate of polymer feeding, pressure of the atomizing
air, drying air flow, and temperature of drying air. An optimization and screening of the experimental parameters by a design
of the experiment (DOE) approach have been done. Finally, the produced spray-dried starch particles were conveniently tested
in a dry coating process, in comparison to the commercial initial starch. The obtained results, in terms of coating efficiency,
demonstrated that the spray-dried particles led to a sharp increase of coating efficiency value. 相似文献