PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 1366832

Optimal temperature control policy for a two-stage recombinant fermentation process.

A Hortacsu·D D Ryu
View original source ↗Export metadata ↓

Abstract

The optimal temperature control policy to be followed in the operation of a two-stage fermentation system in which gene expression is induced by a temperature-sensitive gene switching system was studied. A genetically structured model was used to describe product formation, and kinetic equations based on experimental data were used to quantify the specific gene expression rate and parameters that affect plasmid instability. A constant temperature control policy and temperature profiling control policy including temperature cycling were studied and compared. Maximum average production rate was obtained from a temperature control policy in which the second stage was operated initially at about 40.5 degrees C and the temperature decreased slightly to a constant value at 40.0 degrees C. The maximum average production rate, which corresponds to the optimal temperature control policy, for an operation of 180 h was 29.7 units of protein (mg of cells)-1 h-1.

Explore related subjects

DNA, RecombinantFermentationGene ExpressionKineticsPlasmidsTemperatureJournal ArticleResearch Support, Non-U.S. Gov'tResearch Support, U.S. Gov't, Non-P.H.S.

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

A Hortacsu, D D Ryu. Optimal temperature control policy for a two-stage recombinant fermentation process.. https://doi.org/10.1021/bp00006a001

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2007

Role of SUMO in the dynamics of telomere maintenance in fission yeast.

The sheltering of chromosome ends from illegitimate DNA repair reactions and telomere length homeostasis are critical for preserving genomic integrity. Growing evidence implicates covalent protein modification by SUMO (small ubiquitin-like modifier) (sumoylation) in the regulation of numerous DNA transactions, including DNA repair and transcription, as well as heterochromatin formation and maintenance. We have recently shown that fission yeast Pli1p is a SUMO E3 ligase and that pli1 mutants, which are impaired for global sumoylation, are viable, but exhibit de-regulated homologous recombination and marked defects in chromosome segregation and centromeric silencing, as well as a consistent increase in telomere length. In this work, we explore the mechanisms underlying sumoylation-dependent telomere maintenance. We show that Pli1p, but not the related Nse2p, is the principal SUMO E3 ligase enzyme involved. Using both a pli1 mutation and a physiological "knockdown" of sumoylation, achieved by inducible expression of a dominant negative form of the conjugating enzyme Ubc9p, we further show that telomere lengthening induced by lack of sumoylation is not due to unscheduled telomere-telomere recombination. Instead, sumoylation increases telomerase activity, therefore suggesting that this modification controls the activity of a positive or negative regulator of telomerase.

DNA, Recombinant↗
PubMed2006

Medical innovation, unmet medical needs, and the drug pipeline.

This paper outlines and illustrates the working of a theoretical approach from the social sciences for analyzing medical innovation, unmet medical need, and the drug pipeline. Using the social history of three drugs made from recombinant DNA (insulin, human growth hormone, and tissue-plasminogen activator) the paper shows how drugs can be both technically and organizationally efficient while the needs they satisfy can be created or identified. The paper posits that drugs that require more organizational efficiency tend to satisfy identified, rather then created needs. Key words: Recombinant DNA, technical efficiency, organizational efficiency, anthropology.

DNA, Recombinant↗
PubMed2006

Proteome analysis of mitochondrial outer membrane from Neurospora crassa.

The mitochondrial outer membrane mediates numerous interactions between the metabolic and genetic systems of mitochondria and the rest of the eukaryotic cell. We performed a proteomic study to discover novel functions of components of the mitochondrial outer membrane. Proteins of highly pure outer membrane vesicles (OMV) from Neurospora crassa were identified by a combination of LC-MS/MS of tryptic peptide digests and gel electrophoresis of solubilized OMV proteins, followed by their identification using MALDI-MS PMF. Among the 30 proteins found in at least three of four separate analyses were 23 proteins with known functions in the outer membrane. These included components of the import machinery (the TOM and TOB complexes), a pore-forming component (porin), and proteins that control fusion and fission of the organelle. In addition, proteins playing a role in various biosynthetic pathways, whose intracellular location had not been established previously, could be localized to the mitochondrial outer membrane. Thus, the proteome of the outer membrane can help in identifying new mitochondria-related functions.

DNA, Recombinant↗