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1.
Nisin is a natural peptide used as a preservative in a variety of food products, in which it inhibits mainly Gram-positive bacterial growth, including multidrug-resistant pathogens. However, its application range depends on the cost-effective production and purification of this molecule. Our group has previously produced nisin by Lactococcus lactis cultivation in milk whey, which is an industrial residue from dairy production. To our knowledge, no report used milk whey as a culture medium, although several investigators have purified nisin using different techniques. We thus aimed to establish a low-cost purification of nisin obtained by this process. Samples were diluted in ammonium sulphate, applied onto HIC columns (butyl sepharose CL 4B matrix), and eluted with Milli-Q water or PBS. Elution fractions were monitored for protein content and nisin antibacterial activity. Water elution resulted in purification factor values (270, commercial nisin; 775, nisin produced in-house) higher than those obtained with PBS elution. We concluded that purification of nisin does not require precipitation with ammonium sulphate, therefore allowing step/cost reduction. Moreover, purification from milk whey using HIC provides nisin with high activity and low salt content, which can further be applied to a variety of areas.  相似文献   

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目的探讨疏水层析纯化重组汉逊酵母(Hansenula polymorpha,HP)表达的乙型肝炎表面抗原(HBsAg)层析图谱与蛋白含量及HBsAg含量的相关性。方法采用疏水层析纯化8批HP-HBsAg小量试验样品和5批小量验证试验样品及5批酿酒酵母表达的HBsAg对照试验样品,采用Lowry法和电化学发光法(Electrochemiluminescentimmunoassay,ECLIA)分别检测纯化样品中蛋白含量和HBsAg含量,并计算HBsAg的回收率;通过几何法封闭紫外监测图谱特征峰图形,用数字求积仪采用积分法求出各封闭特征峰的图形面积,并进行分析;取小量验证试验1批样品的层析主峰和副峰收液进行电镜观察。结果 8批HP-HBsAg小量试验和5批HP-HBsAg小量验证试验HBsAg的平均回收率分别为70%和54%。HP-HBsAg疏水层析图谱由两部分构成:穿透峰和目标峰(HBsAg峰),目标峰可见高低不同的两个峰(主峰与副峰);对照图谱中有穿透峰和目标峰。对目标峰进行量化分析,主峰、副峰与目标峰的面积比值分别与其所对应的收集量、蛋白含量和HBsAg含量比值相关。电镜观察可见小量验证试验样品主峰收液中HBsAg颗粒大小均一,副峰收液中HBsAg颗粒大小不均一。结论疏水层析纯化重组HP表达的HBsAg效果良好,通过峰形之间面积比值,可获得峰形所对应的收集量、蛋白量和HBsAg量比值,为HBsAg的进一步纯化提供了参考。  相似文献   

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Process improvement is mainly triggered by quality, safety, environmental considerations or economic potentials. First, ideas for problem solving and the related economic potential need to be analyzed before proceeding to measure, cost and risk assessment.Economic process improvement potentials and options for realization are identified using a Three Stage Method developed in BASF's Process Engineering department. The method is applied to a case study involving two products and a process improvement option.The main tool for this analysis is based on systems technology and material and energy flow analysis. Cost analysis and allocation are based on the results of material and energy flow analysis and provides a basis for developing engineering solutions. The method and the tools are applicable to a wide range of scales including global interactions of production processes and supply chains.  相似文献   

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This article describes a systematic miniplant‐based approach to rapid development of simulated moving bed (SMB) chromatography applications. The methodology involves analysis of single‐column pulse tests to screen adsorbents and operating conditions and to determine initial values of profile advancement factors used to specify flow rates for an initial SMB miniplant experiment. A lumped‐parameter linear driving force rate‐based model is developed by fitting process data from a single miniplant run. The data are fit in a two‐step procedure involving initial determination of effective adsorption isotherm constants as best‐fit parameters with subsequent adjustment of calculated mass transfer coefficients to refine the data fit. The resulting simulation is used to guide further miniplant work and minimize experimental effort. The methodology is illustrated with miniplant data for a binary protein separation showing excellent agreement between model results and process data generated over a wide range of operating conditions. © 2009 American Institute of Chemical Engineers AIChE J, 2009  相似文献   

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This paper presents a systematic methodology for sustainable process systems design, combining the principles of industrial ecology, process design and process integration, Life Cycle Assessment (LCA) and multi-objective optimization (MOO). The superstructure considers an extended decision perimeter and embeds models based either on flowsheeting software or average market technologies, for which energy and material flows are extracted from the Life Cycle Inventory (LCI) database. Therefore, the overall supply chain can be synthesized within a given action system and the systematic recyclings identified. The methodology can be used to design eco-industrial parks or urban systems, to identify the best conversion pathways of resources or waste, or to fix the optimal value of environmental taxes. It is illustrated by an application to the environomic design of an urban energy system. This case study considers multiple energy services to be supplied and waste to be treated, with their seasonal variations, indigenous and imported resources, as well as different candidate conversion technologies. Results demonstrate that integrating an environmental objective in the design procedure leads to consider different system configurations than if only economic aspects are considered. The problematic of the optimal value of a CO2 tax is as well addressed.  相似文献   

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On the basis of the quality by design approach, aggregation of knowledge in process chemistry and manufacturing operations is essential for the continuous development of pharmaceutical products and processes. We develop a model-based framework to describe process chemistry oriented phenomenal sequences leading to quality hazards (process deviation scenario), which should be independent of any specific plant structural information, and manufacturing procedural error oriented event propagations (procedural control scenario), which concern a specific plant structure. We propose a system, Quality-HAZOP, to analyze the scenarios in which manufacturing errors can affect product quality via complex propagation pathways. This system supports bidirectional improvement proposal between recipe scientists and process engineers. This proposal triggers risk information exchange that supports the continuous improvement of the process in life-cycle pharmaceutical development.  相似文献   

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Demands within the pharmaceutical sector to cut costs and improve process efficiencies have grown considerably in recent years. Major challenges exist for companies trying to establish financially viable and robust manufacturing processes for increasingly complex therapeutics. These issues have driven the investigation of miniaturised process‐design techniques by which to identify suitable operating conditions using small volumes of feed material typical of that available in the early stages of bioprocess development. Such techniques are especially valuable for the optimisation of chromatographic separations, which often represent a significant percentage of manufacturing costs and hence for which there is a pressing need to determine the best operating policies. Several methods employing microlitre volumes of sample and resin have been explored recently, which are aimed at the high‐throughput and cost‐effective exploration of the design space for chromatographic separations. This methodology paper reviews these microscale approaches and describes how they work, gives examples of their application, discusses their advantages and disadvantages and provides a comparative assessment of the different methods, along with a summary of the challenges that remain to be overcome in relation to these techniques. Copyright © 2009 Society of Chemical Industry  相似文献   

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A systematic algorithm for simulated moving bed (SMB) chromatography process development that utilizes dynamic optimization, transient experimental data, and parameter estimation to arrive at optimal operating conditions is described. These operating conditions ensure both high purity constraints and optimal productivity are satisfied. This algorithm proceeds until the SMB process is optimized without manual tuning. In a case study, it has been shown with a linear isotherm system that the optimal operating conditions can be reached in only two changes of operating conditions following the proposed algorithm. Another case study with a linear isotherm system has shown that the algorithm is robust to optimize the SMB even if there is significant model mismatch at first. © 2012 American Institute of Chemical Engineers AIChE J, 59: 736–746, 2013  相似文献   

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This paper summarizes the development of an optimized Cu(II)-catalyzed oxidation process for the dimer formation of ApoA-1M, the protein component of an HDL mimic with potential efficacy in atherosclerotic plaque reduction. This oxidation represents a major processing step in the large-scale manufacture of ApoA-1M dimer. The development approach utilizes reaction kinetic modeling, design of experiment, and neural network analysis to establish a quantitative basis for specification of process operating ranges. This work is thus an example of quality by design (QbD) principles where a systematic mechanistic understanding combined with multivariate analysis is integral to process development. Operating within the defined optimum window of operation resulted in both enhanced performance and robustness for the oxidation step in the piloting and manufacturing campaigns.  相似文献   

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Multi-objective optimization of the operation and design of a styrene manufacturing process has been studied with the elitist non-dominated sorting genetic algorithm (NSGA-II). In the first part, the study focused on bi-objective optimization and comparative analysis of three different styrene reactor designs—the single-bed, the steam-injected and the double-bed reactors. The objectives were to simultaneously maximize styrene flow rate and styrene selectivity. In the second part, on the other hand, a tri-objective optimization study was performed involving the entire manufacturing process consisting of the reactor, heat-exchangers and separation units. Only the double-bed reactor was considered in this study for maximizing the styrene flow rate and selectivity and minimizing the total heat duty required by the manufacturing process. Results are presented and discussed in detail.  相似文献   

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The adsorption of proteins to ion exchangers was investigated by finite bath experiments and by computer simulations using existing rate models. Experimental data were obtained for the binding of bovine serum albumin at different feed concentrations to both cation and anion exchangers. The results were interpreted together with model predictions and the values of the parameters characterizing the mass transfer mechanisms as well as the interaction rates of the adsorbate–adsorbent complex were estimated. The best agreement between theory and experiment throughout the whole period of adsorption process was obtained with a complex model where several steps of the overall mechanism were simultaneously controlling the overall rate. The simplified models, which offer rapid solution requiring less computational power, can be used at low feed concentrations of the proteins where the mechanisms controlling the adsorption rate are less complex. As the interaction rate mechanism and the intraparticle mass transfer mechanism in the adsorbent particles are the same in both finite bath and column adsorption systems, the information presented in this paper can be used to predict the protein adsorption in a column chromatography system. © 1997 SCI.  相似文献   

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Lipases from Geotrichum candidum were produced in two different medium: A = 12 % (w/v) clarified corn steep liquor (CCSL) + 0.6 % (w/v) soybean oil (SO) and B = 3.5 % (w/v) yeast hydrolysate (YH) + 0.7 % (w/v) SO. Lipases were partially purified from both media by hydrophobic interaction chromatography using 3.0 mol L?1 of NaCl as mobile phase, and they were characterized in the crude and partially purified forms. The recovery of lipase activity from CCSL and YH via HIC were 96 and 94.3 %, and the purification factors were 44.3 and 86.7‐fold, respectively. All evaluated lipases had similar optimum pH (7.0–7.7), but, for the CCSL crude lipase, optimum temperature (47 °C) was 10 °C higher than others lipases evaluated. CCSL crude lipase possessed a higher thermo stability than YH crude lipase, e.g., at 37 °C (pH 7.0) the half‐life of CCSL crude lipase was 19.25 h and at pH 8.0 (30 °C) the half‐life was 48 h, which are five and ten times higher than with YH crude lipase, respectively. On the other hand, the YH crude lipase possessed a higher catalytic constant (kcat = 2.3 min?1) but with almost the same catalytic efficiency (Km/kcat = 32.12 mg mL min?1) in relation to CCSL crude lipase. The lipases differ in biocatalytic properties between substrates, suggesting that the two lipases can be employed for different applications.  相似文献   

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Ubiquinone (UQ) is a polyisoprenoid lipid found in the membranes of bacteria and eukaryotes. UQ has important roles, notably in respiratory metabolisms which sustain cellular bioenergetics. Most steps of UQ biosynthesis take place in the cytosol of E. coli within a multiprotein complex called the Ubi metabolon, that contains five enzymes and two accessory proteins, UbiJ and UbiK. The SCP2 domain of UbiJ was proposed to bind the hydrophobic polyisoprenoid tail of UQ biosynthetic intermediates in the Ubi metabolon. How the newly synthesised UQ might be released in the membrane is currently unknown. In this paper, we focused on better understanding the role of the UbiJ-UbiK2 heterotrimer forming part of the metabolon. Given the difficulties to gain functional insights using biophysical techniques, we applied a multiscale molecular modelling approach to study the UbiJ-UbiK2 heterotrimer. Our data show that UbiJ-UbiK2 interacts closely with the membrane and suggests possible pathways to enable the release of UQ into the membrane. This study highlights the UbiJ-UbiK2 complex as the likely interface between the membrane and the enzymes of the Ubi metabolon and supports that the heterotrimer is key to the biosynthesis of UQ8 and its release into the membrane of E. coli.  相似文献   

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The optimal design of a compression refrigeration system (CRS) with multiple temperature levels is very important to chemical process industries and also represents considerable challenges in process systems engineering. In this paper, a general methodology for the optimal synthesis of the CRS, which simultaneously integrates CRS and Heat Exchanger Networks (HEN) to minimize the total compressor shaft work consumption based on an MINLP model, has been proposed. The major contribution of this method is in addressing the optimal design of refrigeration cycle with variable refrigeration temperature levels. The method can be used to make major decisions in the CRS design, such as the number of levels, temperature levels, and heat transfer duties. The performance of the developed methodology has been illustrated with a case study of an ethylene CRS in an industrial ethylene plant, and the optimal solution has been examined by rigorous simulations in Aspen Plus to verify its feasibility and consistency.  相似文献   

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The purpose of this work was to demonstrate the use of the AQbD with the DOE approach to the methodical step-by-step development of a UHPLC method for the quantitative determination of the impurity profile of new CPL409116 substance (JAK/ROCK inhibitor) on the preclinical and clinical step of drug discovery studies. The critical method parameters (CMPs) have been tested extensively: the kind of stationary phase (8 different columns), pH of the aqueous mobile phase (2.6, 3.2, 4.0, 6.8), and start (20–25%) and stop (85–90%) percentage of organic mobile phase (ACN). The critical method attributes (CMAs) are the resolution between the peaks (≥2.0) and peak symmetry of analytes (≥0.8 and ≤1.8). In the screening step, the effects of different levels of CMPs on the CMAs were evaluated based on a full fractional design 22. The robustness tests were established from the knowledge space of the screening step and performed by application fractional factorial design 2(4−1). Method operable design region (MODR) was generated. The probability of meeting the specifications for the CMAs was calculated by Monte-Carlo simulations. In relation to literature such a complete AQbD approach including screening, optimization, and validation steps for the development of a new method for the quantitative determination of the full profile of nine impurities of an innovative pharmaceutical substance with the structure-based pre-development pointed out the novelty of our work. The final working conditions were as follows: column Zorbax Eclipse Plus C18, aqueous mobile phase 10 mM ± 1 mM aqueous solution of HCOOH, pH 2.6, 20% ± 1% of ACN at the start and 85% ± 1% of ACN at the end of the gradient, and column temperature 30 °C ± 2 °C. The method was validated in compliance with ICH guideline Q2(R1). The optimized method is specified, linear, precise, and robust. LOQ is on the reporting threshold level of 0.05% and LOD at 0.02% for all impurities.  相似文献   

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