Abstract:
:The effects of dilution rates on the performance of a two-stage fermentation system for a recombinant Escherichia coli culture were studied. Dilution rate determines the apparent or averaged specific growth rate of a heterogeneous population of cells in the recombinant culture. The specific growth rate affects the genetic parameters involved in product formation in the second stage, such as plasmid stability, plasmid content, and specific gene expression rate. Kinetic models and correlations were developed for these parameters based on experimental data. Simulations of plasmid stability in the first stage showed that for longer fermentation periods, plasmid stability is better at higher dilution rates. However, the plasmid content is lower at these dilution rates. The optimal apparent specific growth rate for maximum productivity in the second stage was determined using two methods: (1) direct search for a constant specific growth rate, and (2) dynamic optimization using the maximum principle for a time-dependent specific growth rate profile. The results of the calculations showed that the optimum constant apparent specific growth rate for maximum over-all productivity is 0.40 h(-1). This coincides with the optimal specific growth rate for maximum plasmid content in the expressed stage. A 3.5% increase in overall productivity can be obtained by using a linear time dependent apparent specific growth rate control, micro(2)(t) = 0.0007t, in the course of the fermentation time.
journal_name
Biotechnol Bioengjournal_title
Biotechnology and bioengineeringauthors
Hortacsu A,Ryu DDdoi
10.1002/bit.260380805subject
Has Abstractpub_date
1991-10-20 00:00:00pages
831-7issue
8eissn
0006-3592issn
1097-0290journal_volume
38pub_type
杂志文章abstract::The kinetic properties of acetate-degrading methanogenic granular sludge of different mean diameters were assessed at different up-flow velocities (V(up)). Using this approach, the influence of internal and external mass transfer could be estimated. First, the apparent Monod constant (K(S)) for each data set was calcu...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.1044
更新日期:2001-04-20 00:00:00
abstract::Static and dynamic characteristics of continuous cultures of recombinant methylotrophs, which are designed to improve the selectivity of plasmid-bearing cells and the plasmid stability, are investigated in detail. Operational regions in which coexistence (survival of plasmid-bearing and plasmid-free cells) operation i...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260290802
更新日期:1987-06-01 00:00:00
abstract::A major challenge when designing cell scaffolds for chondrocyte delivery in vivo is creating scaffolds with sufficient mechanical properties to restore initial function while simultaneously controlling temporal changes in the gel structure to facilitate tissue formation. To address this design challenge, degradable ph...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.20160
更新日期:2004-06-30 00:00:00
abstract::Miniaturized bioreactors for suspension cultures of animal cells, such as Chinese Hamster Ovary (CHO) cells, could improve bioprocess development through the ability to cheaply explore a wide range of bioprocess operating conditions. A miniaturized pressure-cycled bioreactor for animal cell cultures, described previou...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.23289
更新日期:2012-01-01 00:00:00
abstract::Pancreatic islet transplantation is a promising alternative to whole-pancreas transplantation as a treatment of type 1 diabetes mellitus. This technique has been extensively developed during the past few years, with the main purpose of minimizing the complications arising from the standard protocols used in organ tran...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章,评审
doi:10.1002/bit.26821
更新日期:2018-12-01 00:00:00
abstract::The G-H loop of foot-and-mouth disease virus is a disordered protrusion of the VP1 protein exposed on the virion surface. This short stretch includes an arginine-glycine-aspartic acid tripeptide, a recognized integrin-binding motif, which is responsible for cell attachment and infection. Eight copies of a peptide repr...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/(sici)1097-0290(19980805)59:3<294::aid-bit
更新日期:1998-08-05 00:00:00
abstract::This study deals with the use of an upward gas/liquid slug flow to reduce tubular mineral membrane fouling. The injection of air into the feedstream is designed to create hydrodynamic conditions that destabilize the cake layer over the membrane surface inside the filtration module complex. Experimental study was carri...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/(sici)1097-0290(19980405)58:1<47::aid-bit5
更新日期:1998-04-05 00:00:00
abstract::Enzymatic acrylation is a process of potentially strong interest to the chemical industry. Direct esterification involving acrylic acid is unfortunately rather slow, with inhibition phenomena appearing at high acid concentrations. In the present study the acrylation of 1-octanol catalyzed by immobilized Candida antarc...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.21706
更新日期:2008-04-15 00:00:00
abstract::Membrane adsorbers may be a viable alternative to the packed-bed chromatography for clearance of virus, host cell proteins, DNA, and other trace impurities. However, incorporation of membrane adsorbers into manufacturing processes has been slow due to the significant cost associated with obtaining regulatory approval ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.24720
更新日期:2013-02-01 00:00:00
abstract::Biosorption of elements is a little understood phenomenon exhibited by some types of even nonliving microbial biomass. A common fungus Rhizopus arrhizus has been reported to take up uranium from aqueous solutions to the extent of 180 mg U(6+)/g. The mechanism of uranium sequestering by this type of biomass was studied...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260240211
更新日期:1982-02-01 00:00:00
abstract::The yeast Pachysolen tannophilus was entrapped in calcium alginate beads to ferment D-xylose on a continous basis in the presence of high cell densities. Experimental operating variables included the feed D-xylose concentration, the dilution rate, and the fermentor biomass concentration. Under favorable operating cond...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260241010
更新日期:1982-10-01 00:00:00
abstract::A desirable feature of many therapeutic glycoprotein production processes is to maximize the final sialic acid content. In this study, the effect of applying a novel chemical analog of the sialic acid precursor N-acetylmannosamine (ManNAc) on the sialic acid content of cellular proteins and a model recombinant glycopr...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.26291
更新日期:2017-08-01 00:00:00
abstract::Being biosurfactants, rhamnolipids create severe foaming when produced in aerobic Pseudomonas aeruginosa fermentation. The necessary reduction of aeration causes oxygen limitation and restricts cell and product concentrations. In this study, we evaluate the new strategy of rhamnolipid production under denitrification ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/1097-0290(20010105)72:1<25::aid-bit4>3.0.c
更新日期:2001-01-05 00:00:00
abstract::The first genome scale model (GSM) for Streptomyces leeuwenhoekii C34 was developed to study the biosynthesis pathways of specialized metabolites and to find metabolic engineering targets for enhancing their production. The model, iVR1007, consists of 1,722 reactions, 1,463 metabolites, and 1,007 genes, it includes th...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.26598
更新日期:2018-07-01 00:00:00
abstract::Addition of Tween 85 to aqueous suspensions of Anabaena variabilis induced photosynthetic evolution of hydrogen over a time span of several weeks: As much as 148 nmol H(2)/h . mg dry weight was produced in the first week by a suspension containing 4.2 mg dry weight of cells and 77 mM Tween 85. The chemical structure o...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260420812
更新日期:1993-10-01 00:00:00
abstract::Metabolite accumulation has pleiotropic, toxic, or beneficial effects on cell physiology, but such effects are not well understood at the molecular level. Cells respond and adapt to metabolite stress by mechanisms largely unexplored, especially in the context of multiple and simultaneous stresses. Solventogenic and re...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.22628
更新日期:2010-04-15 00:00:00
abstract::This article provides the analysis on biomass yields and energetic yields of the oleaginous yeasts. The biomass yields of the oleaginous yeasts are consistently lower than nonoleaginous microorganisms, whereas their energetic yields are higher. Data inconsistencies of literature are explained by the variation of energ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260280117
更新日期:1986-01-01 00:00:00
abstract::We propose that transcript levels for some genes are affected by the bacterial cell division cycle and this may be an important factor to consider when designing synthetic bacterial genomes. To test this hypothesis, transcript levels of 58 genes in Escherichia coli B/r A were determined at five times during the cell d...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.22098
更新日期:2009-02-15 00:00:00
abstract::Lipase from Candida cylindracea (CCL) was incorporated into polymerizable positively charged dialkylammonium bromide surfactant vesicles. The enzyme was incorporated by the use of the dehydration-rehydration method or by incubation. In the latter case, trapping efficiencies of up to 100% could be obtained. Activities ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260420207
更新日期:1993-06-20 00:00:00
abstract::Application of the well-characterized Streptococcus pyogenes CRISPR-Cas9 system in actinomycetes streptomycetes has enabled high-efficiency multiplex genome editing and CRISPRi-mediated transcriptional regulation in these prolific bioactive metabolite producers. Nonetheless, SpCas9 has its limitations and can be ineff...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.27021
更新日期:2019-09-01 00:00:00
abstract::An unadapted mixed methanogenic sludge transformed formaldehyde into methanol and formate. The methanol to formate ratio obtained was 1:1. Formaldehyde conversion proceeded without any lag phase, suggesting the constitutive character of the formaldehyde conversion enzymes involved. Because the rate of formaldehyde con...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.10294
更新日期:2002-08-05 00:00:00
abstract::Hydrophobins are small highly surface-active fungal proteins with potential as biosurfactants in a wide array of applications. However, practical implementation of hydrophobins at large scale has been hindered by low recombinant yields. In this study, the effects of increasing hydrophobin gene copy number and overexpr...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.26982
更新日期:2019-08-01 00:00:00
abstract::In this study we describe a model that estimates the extracellular (nonfungal) and overall water contents of wheat grains during solid-state fermentation (SSF) with Aspergillus oryzae, using on-line measurements of oxygen, carbon dioxide, and water vapor in the gas phase. The model uses elemental balances to predict s...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/1097-0290(20000120)72:2<231::aid-bit11>3.0
更新日期:2001-01-20 00:00:00
abstract::A kinetic model for anaerobic digestion of insoluble solid-state substrates was developed. Rate equations for cell growth and substrate consumption were derived based on the assumption that the microorganisms assimilate the substrate mainly at the point of contact where they grow. The model emphasizes effects of subst...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260350602
更新日期:1990-03-15 00:00:00
abstract::The Waterloo Fast Pyrolysis Process (WFPP) can produce an organic liquid high in levoglucosan (1, 6-anhydro-beta-D-glucopyranose) content from suitably pretreated lignocellulosics. A variety of fungi and yeasts were screened for their ability to utilize and ferment this organic liquid. To enhance its fermentability, t...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260420419
更新日期:1993-08-05 00:00:00
abstract::Seven different supports were compared in solid-phase S(N)Ar and S(N)2 macrocyclization reactions. Product purities were assayed for a relatively facile ring-closure process to give products 1 and 3. Some less-facile ring-closure reactions give the undesired dimeric macrocyclization by-products 2; some of these more-d...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/(sici)1097-0290(200024)71:1<3::aid-bit2>3.
更新日期:2000-01-01 00:00:00
abstract::Pichia pastoris, a methylotrophic yeast, is an efficient producer of recombinant proteins in which the heterologous gene is under the control of the methanol-induced AOX1 promoter. Hence, the accepted production procedure has two phases: In the first phase, the yeast utilizes glycerol and biomass is accumulated; in th...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.10587
更新日期:2003-05-20 00:00:00
abstract::Protein-protein interactions were measured for ovalbumin and for lysozyme in aqueous salt solutions. Protein-protein interactions are correlated with a proposed potential of mean force equal to the free energy to desolvate the protein surface that is made inaccessible to the solvent due to the protein-protein interact...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.10342
更新日期:2002-08-20 00:00:00
abstract::Proteinaceous organic wastes are suitable substrates to produce high added-value products in anaerobic mixed-culture fermentations. In these processes, the stoichiometry of the biotransformation depends highly on operational conditions such as pH or feeding characteristics and there are still no tools that allow the p...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.27177
更新日期:2020-01-01 00:00:00
abstract::Clostridium difficile has emerged as a major cause of infectious diarrhea in hospitalized patients, with increasing mortality rate and annual healthcare costs exceeding $3 billion. Since C. difficile infections are associated with the use of antibiotics, there is an urgent need to develop treatments that can inactivat...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.26029
更新日期:2016-12-01 00:00:00