Abstract:
:Acetate accumulation is a common problem observed in aerobic high cell density Escherichia coli cultures. A previous report has hypothesized that the glyoxylate shunt is active in a low acetate producer, E. coli BL21, and inactive in a high acetate producer, JM109. To further investigate this hypothesis, we now develop a model for the incorporation of (13)C from uniformly labeled glucose into key TCA cycle intermediates. The (13)C isotopomer distributions of oxaloacetate and acetyl-CoA are first determined using NMR and MS techniques. These distributions are next validated by predicting the NMR spectrum of glutamate. Under steady state isotopic conditions, and with knowledge of the full isotopomer distributions of oxaloacetate and acetyl-CoA, the flux ratios through the TCA cycle and the glycoxylate shunt are obtained with respect to the flux through the PPC anaplerotic shunt. We conclude that in BL21, the glyoxylate shunt is active at 22% of the flux through the TCA cycle, and is inactive in JM109. Further, in BL21, the flux through the TCA cycle equals the flux through the PPC shunt, while in JM109 the TCA cycle flux is only third of the flux through the PPC shunt.
journal_name
Biotechnol Bioengjournal_title
Biotechnology and bioengineeringauthors
Noronha SB,Yeh HJ,Spande TF,Shiloach Jsubject
Has Abstractpub_date
2000-05-05 00:00:00pages
316-27issue
3eissn
0006-3592issn
1097-0290pii
10.1002/(SICI)1097-0290(20000505)68:3<316::AID-BITjournal_volume
68pub_type
杂志文章abstract::The discovery of denitrifying anaerobic methane oxidation (DAMO) processes enables the complete nitrogen removal from wastewater by utilizing the methane produced on site from anaerobic digesters. This model-based study investigated the mechanisms and operational window for efficient nitrogen removal by coupling nitri...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.25866
更新日期:2016-05-01 00:00:00
abstract::Membrane chromatography (MC) systems are finding increasing use in downstream processing trains for therapeutic proteins due to the unique mass-transfer characteristics they provide. As a result, there is increased need for model-based methods to scale-up MC units using data collected on a scaled-down unit. Here, a st...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.25217
更新日期:2014-08-01 00:00:00
abstract::An approach is presented for the stable covalent immobilization of proteins with a high retention of biological activity. First, chemical modification studies were used to establish enzyme structural and functional properties relevant to the covalent immobilization of an enzyme to agarose based supports. Heparinase wa...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260370305
更新日期:1991-02-05 00:00:00
abstract::Detachment from biofilms was evaluated using a mixed culture biofilm grown on primary wastewater in a tube reactor. The growth of biofilms and the detachment of biomass from biofilms are strongly influenced by hydrodynamic conditions. In a long-term study, three biofilms were cultivated in a biofilm tube reactor. The ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.10503
更新日期:2003-03-05 00:00:00
abstract::The effects of external calcium concentrations on biosynthesis of ginsenoside Rb1 and several calcium signal sensors were quantitatively investigated in suspension cultures of Panax notoginseng cells. It was observed that the synthesis of intracellular ginsenoside Rb1 in 3-day incubation was dependent on the medium Ca...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.20386
更新日期:2005-02-20 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::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 polyvinylpyridi...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260470405
更新日期:1995-08-20 00:00:00
abstract::The budding yeast Saccharomyces cerevisiae is equipped with G protein-coupled receptors (GPCR). Because the yeast GPCR signaling mechanism is partly similar to that of the mammalian system, S. cerevisiae can be used for a host of mammalian GPCR expression and ligand-mediated activation assays. However, currently avail...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.26255
更新日期:2017-06-01 00:00:00
abstract::Two instruments were developed to mechanize the handling of anaerobic microorganisms for microbial mutant isolation. The instruments automatically dispense liquid or agar medium to large and small 96-well platesand petridishes. Protocols were developed for inoculating different microorganisms, and calibration curves o...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260280905
更新日期:1986-09-01 00:00:00
abstract::Flocculation of yeast cells occurs during the fermentation of beer. Partway through the fermentation the cells become flocculent and start to form flocs. If the environmental conditions, such as medium composition and fluid velocities in the tank, are optimal, the flocs will grow in size large enough to settle. After ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/(sici)1097-0290(19980205)57:3<330::aid-bit
更新日期:1998-02-05 00:00:00
abstract::The paper reviews the state-of-the-art in computational modeling of thrombus formation and growth and related phenomena including platelet margination, activation, adhesion, and embolization. Presently, there is a high degree of empiricism in the modeling of thrombus formation. Based on the experimentally observed phy...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章,评审
doi:10.1002/bit.26343
更新日期:2017-10-01 00:00:00
abstract::Among various routes for the biological hydrogen production, the NAD(P)H-dependent pentose phosphate (PP) pathway is the most efficient for the dark fermentation. Few studies, however, have focused on the glucose-6-phosphate 1-dehydrogenase, encoded by zwf, as a key enzyme activating the PP pathway. Although the gluco...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.23259
更新日期:2011-12-01 00:00:00
abstract::The adsorption of cellulase on cellulose and a lignacious residue was examined by using cellulase from Trichoderma reesei, hardwood pretreated by dilute sulfuric acid under high pressure, and a lignacious residue prepared by a complete enzymatic hydrolysis of the pretreated wood. A significant amount of cellulase was ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260360503
更新日期:1990-08-20 00:00:00
abstract::Peroxidase-catalyzed asymmetric sulfoxidations, while synthetically attractive, suffer from relatively low reaction rates due to poor substrate solubilities in water and from appreciable spontaneous oxidation of substrates (especially aryl alkyl sulfides) with H(2)O(2). In this work, we found that both of these shortc...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/1097-0290(20001105)70:3<353::aid-bit13>3.0
更新日期:2000-11-05 00:00:00
abstract::Actively growing Escherichia coli C600(pBR322), immobilized within the macroporous matrix of asymmetric-wall hollow-fiber membranes, has been propagated to extremely high densities, typically more than 10(12) cells/mL of accessible void volume, in some regions cells accounting for nearly 100% of the available macrovoi...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260251113
更新日期:1983-11-01 00:00:00
abstract::An integrated approach is used to develop a rapid sampling strategy for the quantitative analysis of in vivo kinetic behavior based on measured concentrations of intracellular metabolites in Saccharomyces cerevisiae. Emphasis is laid on small sample sizes during sampling and analysis. Subsecond residence times are acc...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.10048
更新日期:2001-11-20 00:00:00
abstract::Bacterial profile modification (BPM), a form of tertiary oil recovery, diverts water from the water-flooded high-permeability zone into the oil-bearing low-permeability zone. During field use, exopolymer-producing bacteria plug the high-permeability zone only in the immediate vicinity of the injection point (the near-...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.20315
更新日期:2005-01-05 00:00:00
abstract::N-linked glycan distribution affects important end-use characteristics such as the bioactivity and efficacy of many therapeutic proteins, (including monoclonal antibodies), in vivo. Yet, obtaining desired glycan distributions consistently during batch-to-batch production can be challenging for biopharmaceutical manufa...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.25251
更新日期:2014-10-01 00:00:00
abstract::As the therapeutic monoclonal antibody (mAb) market continues to grow, optimizing production processes is becoming more critical in improving efficiencies and reducing cost-of-goods in large-scale production. With the recent trends of increasing cell culture titers from upstream process improvements, downstream capaci...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.24377
更新日期:2012-04-01 00:00:00
abstract::Hairy roots grow quickly, reach high densities, and can produce significant amounts of secondary metabolites, yet their scale-up to bioreactors remains challenging. Artemisia annua produces a rich array of terpenoids, including the sesquiterpene, artemisinin, and transformed roots of this species provide a good model ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.10711
更新日期:2003-09-20 00:00:00
abstract::Frozen bagged seed inoculum was prepared, thawed and tested for seven cultures. Thawing techniques were developed and other key influences on thawing rate were quantified; seed bag thawing without a water bath rarely required more than 4 to 5 h and was as short as 0.5 to 1 h for lower fill volume bags. Testing include...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.10323
更新日期:2002-09-20 00:00:00
abstract::Capitalizing on components evolved to metabolize ethanol in Aspergillus nidulans, we previously designed the first molecular gas-gene expression interface using gaseous acetaldehyde as the major inducer. This fungus-derived acetaldehyde-inducible gene regulation (AIR) system operated perfectly and enabled precise and ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.20482
更新日期:2005-06-30 00:00:00
abstract::The effects of growing Clostridium acetobutylicum NCIB 8052 in a chemostat under conditions of glucose, NH(4) (+), PO(4) (3-), Mg(2+), and Fe(2+) limitation were examined. It was noted that limitation of any major nutrient resulted in the same fermentation pattern. Conditions where minor nutrient levels were reduced a...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260290315
更新日期:1987-02-01 00:00:00
abstract::Three-dimensional cell culture models, such as spheroids, can be used in the process of the development of new anticancer agents because they are able to closely mimic the main features of human solid tumors, namely their structural organization, cellular layered assembling, hypoxia, and nutrient gradients. These prop...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章,评审
doi:10.1002/bit.26845
更新日期:2019-01-01 00:00:00
abstract::A method was developed for obtaining high signal-to-noise 13C NMR spectra of intracellular compounds in metabolically active cultured cells. The method allows TCA cycle labeling kinetics to be determined in real time without significant oxygen transport limitations. Cells were immobilized on the surface of nonporous m...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.20191
更新日期:2004-09-30 00:00:00
abstract::Current techniques for characterizing biofilm physiology lack the signal filtering capability required for quantifying signals associated with real time biologically active transport. Though a great deal was learned from previous investigations, no results have been reported on the characterization of in vivo, real ti...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.22128
更新日期:2009-02-15 00:00:00
abstract::A limited life cycle assessment (LCA) was performed on a combined biological and chemical process for the production of adipic acid, which was compared to the traditional petrochemical process. The LCA comprises the biological conversion of the aromatic feedstocks benzoic acid, impure aromatics, toluene, or phenol fro...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.23074
更新日期:2011-06-01 00:00:00
abstract::CTLA4 is a membrane receptor on cytotoxic T cells whose interaction with the B7 counterreceptor on B cells is important in alloantigen responses. Soluble recombinant human and murine CTLA4 were produced using either Chinese hamster ovary or NS-0 cell lines. Expression vectors were constructed containing the gene codin...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260460502
更新日期:1995-06-05 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::Genome-scale flux analysis of Escherichia coli DH5alpha growth in a complex medium was performed to investigate the relationship between the uptake of various nutrients and their metabolic outcomes. During the exponential growth phase, we observed a sequential consumption order of serine, aspartate and glutamate in th...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.22119
更新日期:2009-02-15 00:00:00