Abstract:
:Recent studies have demonstrated the feasibility of using ultrafiltration for the purification of plasmid DNA, but there is still little understanding of the factors governing DNA transmission. Experimental data were obtained for the transmission of a 3.0 kbp supercoiled plasmid DNA through composite regenerated cellulose ultrafiltration membranes as a function of solution ionic environment in a stirred ultrafiltration cell. The dependence on salt concentration was quite dramatic, with the sieving coefficient increasing by more than 80-fold as the NaCl concentration increased from 1 to 150 mM at a fixed filtrate flux. At the same total ionic strength, the sieving coefficient in an MgCl2 solution was significantly larger than that evaluated in NaCl. The sieving results are consistent with independent studies showing a reduction in the effective plasmid size due to salt specific shielding of intramolecular electrostatic interactions. DNA transmission was also a strong function of the filtrate flux, with negligible transmission below a critical value of the flux. The predicted values of the critical filtrate flux determined using a modified elongational flow model were in excellent agreement with the experimental data. These results clearly demonstrate that salt-induced changes in plasmid DNA structure have a significant effect on plasmid DNA transmission through ultrafiltration membranes.
journal_name
Biotechnol Bioengjournal_title
Biotechnology and bioengineeringauthors
Latulippe DR,Zydney ALdoi
10.1002/bit.21575subject
Has Abstractpub_date
2008-02-01 00:00:00pages
390-8issue
2eissn
0006-3592issn
1097-0290journal_volume
99pub_type
杂志文章abstract::The hydrolysis of lactose by a beta-galactosidase from the thermophilic microorganism Thermus sp. strain T2, both in solution and immobilized on a commercial silica-alumina, has been studied. The enzyme has been previously produced by Escherichia coli JM101 harboring the plasmid pBGT1, which contains the codifying gen...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.10466
更新日期:2003-01-20 00:00:00
abstract::A novel method has been developed for the separation of bioproducts from yeast cells. The method uses a combination of physical, chemical, and biological agents such as lytic enzymes, osmotic supports, and spheroplast stabilizers. Using this technique, products (proteins and enzymes) can be released from specific cell...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260380904
更新日期:1991-11-01 00:00:00
abstract::The development of new gene delivery technologies is a prerequisite towards gene therapy clinical trials. Because gene delivery mediated by viral vectors remains of limited scope due to immunological and propagation risks, the development of new non-viral gene delivery systems is of crucial importance. We have synthes...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:
更新日期:1998-04-01 00:00:00
abstract::A computer-controlled headspace gas chromatograph was used to monitor the progress of ethanol production from both aerobic batch and anaerobic continuous fermentations. Using an automatic, electropneumatic sampling system, aliquots of fermentation headspace gas were injected directly onto the column for quantitative e...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260251103
更新日期:1983-11-01 00:00:00
abstract::Morphology has a crucial effect on productivity and the supply of substrate for cultures of filamentous fungi. However, cultivation parameters leading to the desired morphology are often chosen empirically as the mechanisms governing the processes involved are usually unknown. For coagulating microorganisms like Asper...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.20130
更新日期:2004-07-20 00:00:00
abstract::Ralstonia eutropha grows on and produces polyhydroxyalkanoates (PHAs) from fermentation acids. Acetic acid, one major organic acid from acidogenesis of organic wastes, has an inhibitory effect on the bacterium at slightly alkaline pH (6 g HAc/L at pH 8). The tolerance of R. eutropha to acetate, however, was increased ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.1080
更新日期:2001-06-20 00:00:00
abstract::Short-chain carboxylic acids generated by various mixed- or pure-culture fermentation processes have been considered valuable precursors for production of bioalcohols. While conversion of carboxylic acids into alcohols is routinely performed with catalytic hydrogenation or with strong chemical reducing agents, here, a...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.24786
更新日期:2013-04-01 00:00:00
abstract::Acid phosphatase thermal deactivation follows a complex path: an initial decay toward an equilibrium distribution of at least two intermediate structures, mutually at the equilibrium, followed by a final breakdown toward a completely inactive enzyme configuration. The results obtained in the presence of sorbitol have ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260381006
更新日期:1991-12-05 00:00:00
abstract::Porcine pancreatic lipase and Fusarium solani cutinase were used to catalyze transesterification reactions between methyl propionate, ethyl propionate, and a series of primary alcohols at high temperatures in a continuous packed-bed gas-solid reactor, in which the solid phase is composed of the enzyme and the substrat...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260390415
更新日期:1992-02-20 00:00:00
abstract::A framework using material balances in metabolic pathways to study cellular metabolism is examined and the results are discussed. Rate measurements on extracellular compounds alone were found to be not always sufficient to validate proposed unique intracellular mechanisms. The conditions to delineate among candidate m...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260340409
更新日期:1989-08-05 00:00:00
abstract::We studied the resolution of racemic glycidol through esterification with butyric acid catalyzed by porcine pancreatic lipase in organic media. A screening of seven solvents (log P values between 0.49 and 3.0, P being the n-octanol-water partition coefficient of the solvent) showed that neither log P nor the logarithm...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260420409
更新日期:1993-08-05 00:00:00
abstract::For the commercial exploitation of lipase biocatalysis to be successful, it is essential that effective supports are selected for lipase immobilization. In this study hydrophobic controlled-pore glasses have been used as model systems for the immobilization of Rhizomucor miehei lipase. The effect of pore diameter and ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260431006
更新日期:1994-04-25 00:00:00
abstract::Clostridium tyrobutyricum ATCC 25755 is known as a natural hyper-butyrate producer with great potentials as an excellent platform to be engineered for valuable biochemical production from renewable resources. However, limited transformation efficiency and the lack of genetic manipulation tools have hampered the broade...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.27435
更新日期:2020-09-01 00:00:00
abstract::The implementation of control algorithms to batch bioreactors is often complicated by variations in process dynamics that occur during the course of fermentation. Such a wide operating range often renders the performance of fixed gain proportional-integral-differential (PID) controllers unsatisfactory. In this work, d...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260320415
更新日期:1988-08-05 00:00:00
abstract::Two thermophilic bacteria, Thermus aquaticus ATCC 25104 and Thermus species ATCC 27978, were investigated for their abilities to degrade BTEX (benzene, toluene, ethylbenzene, and xylenes). Thermus aquaticus and the Thermus sp. were grown in a nominal medium at 70 degrees C and 60 degrees C, respectively, and resting c...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260480609
更新日期:1995-12-20 00:00:00
abstract::Stem cell self-renewal versus differentiation fate decisions are difficult to characterize and analyze due to multiple competing rate processes occurring simultaneously among heterogeneous cell subpopulations. To address this challenge, we describe a mathematical model for cell population dynamics that allows flow cyt...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.20244
更新日期:2004-11-05 00:00:00
abstract::A nuclear magnetic resonance (NMR) method has been developed to monitor on-line lipase-catalyzed esterification reactions without the need to sample the reaction medium. The technique, through (1)H NMR, measures the concentrations of alcohol, ester, hydroxylic hydrogens in the organic phase, and hydroxylic hydrogens i...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/(SICI)1097-0290(19960920)51:6<636::AID-BIT
更新日期:1996-09-20 00:00:00
abstract::This paper describes a novel surface immobilization method for live-cell imaging of Chlamydomonas reinhardtii for continuous monitoring of lipid droplet accumulation. Microfluidics allows high-throughput manipulation and analysis of single cells in precisely controlled microenvironment. Fluorescence imaging based quan...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.25453
更新日期:2015-03-01 00:00:00
abstract::A recently discovered thermophilic bacterium, Geobacillus thermoglucosidasius M10EXG, ferments a range of C5 (e.g., xylose) and C6 sugars (e.g., glucose) and is tolerant to high ethanol concentrations (10%, v/v). We have investigated the central metabolism of this bacterium using both in vitro enzyme assays and 13C-ba...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.22181
更新日期:2009-04-01 00:00:00
abstract::Animal cell cultivation in vitro has been studied for more than 40 years. However, the culture medium composition has not been designed on the basis of the stoichiometric nutritional demands for animal cell growth. In this article, a model was developed to study the stoichiometric demands for nutrients (including gluc...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260431122
更新日期:1994-05-01 00:00:00
abstract::Metabolically active resting (i.e., nongrowing) bacterial cells have a high potential in cofactor-dependent redox biotransformations. Where growing cells require carbon and energy for biomass production, resting cells can potentially exploit their metabolism more efficiently for redox biocatalysis allowing higher spec...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.24404
更新日期:2012-05-01 00:00:00
abstract::We consider the application of high-throughput experimentation (HTE), including combinatorial methods, to catalyst discovery and early-phase optimization. While combinatorial- and parallel-testing methods have an already substantial history in catalysis, recent work by several groups promises significant efficiency ga...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/(sici)1097-0290(1998)61:4<203::aid-cc3>3.0
更新日期:1998-01-01 00:00:00
abstract::The microbial degradation of quinoline by Comamonas acidovorans was studied in a laboratory scale stirred tank reactor. In continuous culture experiments using quinoline as a sole source of carbon and nitrogen, it was shown by means of mass balances that quinoline was converted completely to biomass, carbon dioxide, a...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260420506
更新日期:1993-08-20 00:00:00
abstract::The kinetics in batch culture of the acetone butanol fermentation by Clostridium acetobutylicum is compared on glucose, xylose, and mixtures of both sugars. The fastest initial growth and transition from an acid to a solvent metabolism occurs on glucose, with a final 62 g/L glucose conversion. On xylose, an initial sl...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260280203
更新日期:1986-02-01 00:00:00
abstract::Mathematical modeling of animal cell growth and metabolism is essential for the understanding and improvement of the production of biopharmaceuticals. Models can explain the dynamic behavior of cell growth and product formation, support the identification of the most relevant parameters for process design, and signifi...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.27288
更新日期:2020-05-01 00:00:00
abstract::Utilization of renewable feedstocks for the production of bio-based chemicals such as d-lactic acid by engineering metabolic pathways in the yeast Saccharomyces cerevisiae has recently become an attractive option. In this study, to realize efficient d-lactic acid production by S. cerevisiae, the expression of 12 glyco...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.26330
更新日期:2017-09-01 00:00:00
abstract::The production of heterologous proteins by secretion from cellular hosts is an important determinant for the cost of biotherapeutics. A single-cell analytical method called microengraving was used to examine the heterogeneity in secretion by the methylotrophic yeast Pichia pastoris. We show that constitutive secretion...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.22688
更新日期:2010-06-01 00:00:00
abstract::Membrane morphology is compared to protein depostion under passive adsorption and ultrafiltration conditions. Solute resistance of protein deposits for membranes of varying roughness, structure, and permeability can vary dramatically with operating conditions. Using Brunauer-Emmett-Teller adsorption isotherm (BET), st...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260470208
更新日期:1995-07-20 00:00:00
abstract::Protein engineering is a powerful tool for improving the properties of enzymes. However, large changes in enzyme properties are still challenging for traditional evolution strategies because they usually require multiple amino acid substitutions. In this study, a feasible evolution approach by a combination of fragmen...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.27203
更新日期:2020-02-01 00:00:00
abstract::The growth and product formation of a Savinase-producing Bacillus clausii were investigated in high-cell-density fed-batch cultivations with both linear and exponential feed profiles. The highest specific productivity of Savinase was observed shortly after the end of the initial batch phase for all feed profiles appli...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.10675
更新日期:2003-08-05 00:00:00