Abstract:
:A model was developed to evaluate the effects of cells and surfactants on oxygen transfer in surface-aerated bioreactors. The model assumed the presence of serial layers of adsorbed surfactants and microorganisms directly adjacent to the gas-liquid interface due to their surface activities, followed by a stagnant liquid layer to account for the oxygen transfer resistance in the liquid phase. The interfacial surfactant film, although posing as an additional resistance, was found to have negligible effect on the oxygen transfer rate because of its extremely small thickness as compared to the cell monolayer and the stagnant liquid layer. On the other hand, cells affect oxygen transfer by two mechanisms: the biological enhancement due to the respiration of interfacial cells and the physical blocking resulting from the semipermeable nature of cell bodies. Due to the low specific oxygen uptake rates of the sludges, the two mechanisms were found to be of comparable importance in activated-sludge systems; the oxygen transfer enhancement factor, E, varied from about 0.97 to 1.10 depending on the operating conditions. The biological enhancement effect, however, predominated in fermentations of actively growing bacteria. At relatively low agitation speed (e. g., 300 rpm), the value of E could reach about 3 to 5 in fermentations with high cell concentrations. Effects of other operating variables, such as the agitation intensity, the oxygen content in the mixed liquor, and the bulk cell concentration, on biological oxygen transfer enhancement were also studied.
journal_name
Biotechnol Bioengjournal_title
Biotechnology and bioengineeringauthors
Ju LK,Sundarajan Adoi
10.1002/bit.260401108subject
Has Abstractpub_date
1992-12-20 00:00:00pages
1343-52issue
11eissn
0006-3592issn
1097-0290journal_volume
40pub_type
杂志文章abstract::The ability to capture cell-free DNA from the gastrointestinal tract, in a minimally invasive manner, could enhance our ability to diagnose gastrointestinal disease, or gain a better understanding of the spatial mapping of the intestinal microbiota. We, therefore, sought to identify a class of capture agents that coul...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.26207
更新日期:2017-04-01 00:00:00
abstract::Disulfide-rich peptides isolated from cone snails are of great interest as drug leads due to their high specificity and potency toward therapeutically relevant ion channels and receptors. They commonly contain the inhibitor cystine knot (ICK) motif comprising three disulfide bonds forming a knotted core. Here we repor...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.25993
更新日期:2016-10-01 00:00:00
abstract::Monolith reactors combine good mass transfer characteristics with low-pressure drop, the principle factors affecting the cost effectiveness of industrial processes. Recently, these specific features of the monolith reactors have drawn the attention toward the application of the monolith reactor in multiphase reaction ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.20674
更新日期:2006-02-05 00:00:00
abstract::Chlorophyllide a was coupled with alpha-(3-aminopropyl)-omega-methoxypoly(oxyethylene) (PEG-NH2) to form a PEG-chlorophyllide conjugate through an acid-amide bond. The conjugate catalyzed the reduction of methylviologen in the presence of 2-mercaptoethanol. It also catalyzed the photoreduction of NADP+ or NAD+ in the ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.1029
更新日期:2001-01-01 00:00:00
abstract::The effect of hydrogen and carbon dioxide partial pressure on the growth of the extremely thermophilic archaebacterium Pyrodictium brockii at 98 degrees C was investigated. Previous work with this bacterium has been done using an 80:20 hydrogen-carbon dioxide gas phase with a total pressure of 4 atm; no attempt has be...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260320405
更新日期:1988-08-05 00:00:00
abstract::Neural stem cells (NSCs) are undifferentiated, primitive cells with important potential applications including the replacement of neural tissue lost due to neurodegenerative diseases, including Parkinson's disease, as well as brain and spinal cord injuries, including stroke. We have developed methods to rapidly expand...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.20246
更新日期:2004-11-05 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::Nitrous oxide (N2 O), a potent greenhouse gas, is reduced to N2 gas by N2 O-reducing bacteria (N2 ORB), a process which represents an N2 O sink in natural and engineered ecosystems. The N2 O sink activity by N2 ORB depends on temperature and O2 exposure, yet the specifics are not yet understood. This study explores th...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.27654
更新日期:2020-12-11 00:00:00
abstract::The production of dry-grind corn ethanol results in the generation of intermediate products, thin and whole stillage, which require energy-intensive downstream processing for conversion into commercial animal feed products. Hydrothermal carbonization of thin and whole stillage coupled with anaerobic digestion was inve...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.24924
更新日期:2013-10-01 00:00:00
abstract::C-terminal lysine (C-K) variants are commonly observed in therapeutic monoclonal antibodies and recombinant proteins. Heterogeneity of C-K residues is believed to result from varying degree of proteolysis by endogenous carboxypeptidase(s) during cell culture production. The achievement of batch-to-batch culture perfor...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.24510
更新日期:2012-09-01 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::Microbial degradation of trichloroethylene (TCE) has been demonstrated under aerobic conditions with propane. The primary objective of this research was to evaluate the feasibility of introducing a vapor phase form of TCE in the presence of propane to batch bioreactors containing a liquid phase suspension of Mycobacte...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260460406
更新日期:1995-05-20 00:00:00
abstract::A stirred bath technique was developed for determining effective diffusivities in cell matrices. The technique involves cell immobilization in a dilute gel which has negligible effect on solute diffusion. Agar and collagen were tested as immobilizing gels. Agar gel was shown to have minor interactions with the diffusi...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260320810
更新日期:1988-10-05 00:00:00
abstract::Pulses of several nonreacting solutes were fed to a column containing immobilized enzyme catalyst beads. The response curves were recorded, and their first and second moments were determined by numerical integration. From the moment analysis, the void volume, internal porosity, and tortuosity of the support were calcu...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260250707
更新日期:1983-07-01 00:00:00
abstract::The placement of the reference electrode (RE) in various bioelectrochemical systems is often varied to accommodate different reactor configurations. While the effect of the RE placement is well understood from a strictly electrochemistry perspective, there are impacts on exoelectrogenic biofilms in engineered systems ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.25253
更新日期:2014-10-01 00:00:00
abstract::One of the critical problems in scale-up of affinity chromatography is the mechanical strength of the support matrix against pressure. Because the costs of both the gel matrix and the ligand for the affinity chromatography are very high, the reusability of gel matrices is directly related to the total production cost....
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260391104
更新日期:1992-05-01 00:00:00
abstract::The spatial cell-material interaction remains vital issue in forming biodegradable scaffolds in Tissue Engineering. In this study, to understand the influence of spatial architecture on cellular behavior, 2D and 3D chitosan scaffolds of 50-190 kD and >310 kD MW were synthesized through air drying and controlled rate f...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.20703
更新日期:2006-01-05 00:00:00
abstract::Polyhydroxyalkanoates (PHA) terployesters P(3HB-co-3HV-co-3HHx) consisting of 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV), and 3-hydroxyhexanoate (3HHx) were produced by wild-type Aeromonas hydrophila 4AK4, its recombinant harboring PHA synthesis genes phaPCJ encoding PHA binding protein phasin, PHA synthase, and...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.22409
更新日期:2009-10-15 00:00:00
abstract::In this study, white rot fungus, Polyporus brumalis, was applied to degrade dibutyl phthalate (DBP), a major environmental pollutant. The degradation potential and resulting products were evaluated with HPLC and GC/MS. As DBP concentration increased to 250, 750, and 1,250 microM, the mycelial growth of P. brumalis was...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.21333
更新日期:2007-08-15 00:00:00
abstract::A method for purifying alpha-amylase inhibitor from wheat meal based on immobilized metal affinity with a thermosensitive copolymer is developed. The studies represent the thermoprecipitation properties of the copolymers of N-isopropylacrylamide (NIPAM) with iminodiacetic acid (IDA) and 1-vinylimidazole (VI), respecti...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/(sici)1097-0290(19980920)59:6<695::aid-bit
更新日期:1998-09-20 00:00:00
abstract::The evolution of microbial populations involved in simulated-heap leaching of a polymetallic black schist sulfide ore (from the recently-commissioned Talvivaara mine, Finland) was monitored in aerated packed bed column reactors over a period of 40 weeks. The influence of ore particle size (2-6.5 mm and 6.5-12 mm) on c...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.21951
更新日期:2008-11-01 00:00:00
abstract::Based on the recently constructed Escherichia coli itaconic acid production strain ita23, we aimed to improve the productivity by applying a two-stage process strategy with decoupled production of biomass and itaconic acid. We constructed a strain ita32 (MG1655 ΔaceA Δpta ΔpykF ΔpykA pCadCs), which, in contrast to ita...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.26446
更新日期:2018-01-01 00:00:00
abstract::Aggregates of Escherichia coli confined within hollowfiber reactors were either formed in place by culturing cells within the reactors, or were prepared by injecting a cell suspension that had been concentrated by centrifugation. The effective diffusive permeability of an uncharged nonreacting tracer, nitrous oxide, w...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260320111
更新日期:1988-06-20 00:00:00
abstract::All bacteria release organic compounds called soluble microbial products (SMP) as a part of their normal metabolism. In photobioreactor (PBR) settings, SMP produced by cyanobacteria represent a major pool of carbon and electrons available to heterotrophic bacteria. Thus, SMP in PBRs are a major driver for the growth o...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.25602
更新日期:2015-09-01 00:00:00
abstract::Small interfering RNAs (siRNAs) are invaluable research tools for studying gene functions in mammalian cells. siRNAs are mainly produced by chemical synthesis or by enzymatic digestion of double-stranded RNA (dsRNA) produced in vitro. Recently, bacterial cells, engineered with ectopic plant viral siRNA binding protein...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.26740
更新日期:2018-09-01 00:00:00
abstract::Fungal biofilters have been recently studied as an alternative to the bacterial systems for the elimination of hydrophobic volatile organic compounds (VOC). Fungi foster reduced transport limitation of hydrophobic VOCs due to their hydrophobic surface and extended gas exchange area associated to the hyphal growth. Nev...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.23003
更新日期:2011-04-01 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::The emissions of nitrous oxide (N(2)O) and nitric oxide (NO) from biological nitrogen removal (BNR) operations via nitrification and denitrification is gaining increased prominence. While many factors relevant to the operation of denitrifying reactors can influence N(2)O and NO emissions from them, the role of differe...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.22704
更新日期:2010-06-15 00:00:00
abstract::This communication demonstrates that two-phase aqueous mixed (nonionic/ionic) micellar systems have the potential for improving the separation of proteins from viruses. Specifically, two separation experiments were performed to show that the addition of the anionic surfactant sodium dodecyl sulfate (SDS) to the two-ph...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.10377
更新日期:2002-10-20 00:00:00
abstract::Hemicellulose residues can be hydrolyzed into a sugar syrup using dilute mineral acids. Although this syrup represents a potential feedstock for biofuel production, toxic compounds generated during hydrolysis limit microbial metabolism. Escherichia coli LY01, an ethanologenic biocatalyst engineered to ferment the mixe...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/(sici)1097-0290(1999)66:4<203::aid-bit1>3.
更新日期:1999-01-01 00:00:00