Physiological conditions conducive to high cell density and high cyanophycin content in Ralstonia eutropha strain H16 possessing a KDPG aldolase gene-dependent addiction system

Polyhydroxyalkanoates (PHAs) are biodegradable plastic-like materials with versatile properties. Plant oils are excellent carbon sources for a cost-effective PHA production, due to their high carbon content, large availability, and comparatively low prices. Additionally, efficient process development and control is required for competitive PHA production, which can be facilitated by on-line or in-line monitoring devices. To this end, we have evaluated photon density wave (PDW) spectroscopy as a new process analytical technology for Ralstonia eutropha (Cupriavidus necator) H16 plant oil cultivations producing polyhydroxybutyrate (PHB) as an intracellular polymer. PDW spectroscopy was used for in-line recording of the reduced scattering coefficient µs’ and the absorption coefficient µa at 638 nm. A correlation of µs’ with the cell dry weight (CDW) and µa with the residual cell dry weight (RCDW) was observed during growth, PHB accumulation, and PHB degradation phases in batch and pulse feed cultivations. The correlation was used to predict CDW, RCDW, and PHB formation in a high-cell-density fed-batch cultivation with a productivity of 1.65 gPHB·L−1·h−1 and a final biomass of 106 g·L−1 containing 73 wt% PHB. The new method applied in this study allows in-line monitoring of CDW, RCDW, and PHA formation.

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A novel high-cell-density recombinant protein production system based on Ralstonia eutropha.

10.1349/ddlp.31 ◽

2003 ◽

Author(s):

Sriram Srinivasan

Keyword(s):

Recombinant Protein ◽

Cell Density ◽

Production System ◽

Recombinant Protein Production ◽

Protein Production ◽

Ralstonia Eutropha ◽

High Cell Density ◽

High Cell

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Expression and recovery of recombinant proteins in a novel high cell density prokaryotic system based on Ralstonia eutropha.

10.1349/ddlp.45 ◽

2004 ◽

Author(s):

Gavin C. Barnard

Keyword(s):

Cell Density ◽

Recombinant Proteins ◽

Ralstonia Eutropha ◽

High Cell Density ◽

High Cell

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Modeling of poly(3-hydroxybutyrate) production by high cell density fed-batch culture of Ralstonia eutropha

Biotechnology and Bioprocess Engineering ◽

10.1007/bf02931065 ◽

2007 ◽

Vol 12 (4) ◽

pp. 417-423 ◽

Cited By ~ 10

Author(s):

Longan Shang ◽

Dai Di Fan ◽

Moon Il Kim ◽

Jin-dal-rae Choi ◽

Ho Nam Chang

Keyword(s):

Cell Density ◽

Batch Culture ◽

Ralstonia Eutropha ◽

High Cell Density ◽

High Cell ◽

Fed Batch ◽

Fed Batch Culture

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A Novel High-Cell-Density Protein Expression System Based on Ralstonia eutropha

Applied and Environmental Microbiology ◽

10.1128/aem.68.12.5925-5932.2002 ◽

2002 ◽

Vol 68 (12) ◽

pp. 5925-5932 ◽

Cited By ~ 35

Author(s):

Sriram Srinivasan ◽

Gavin C. Barnard ◽

Tillman U. Gerngross

Keyword(s):

Protein Expression ◽

Cell Density ◽

Ralstonia Eutropha ◽

High Cell Density ◽

Expression System ◽

High Cell ◽

Protein Expression System ◽

Inclusion Body Formation ◽

High Density Cell ◽

High Level

ABSTRACT We describe the development of a novel protein expression system based on the industrial fermentation organism Ralstonia eutropha (formerly known as Alcaligenes eutrophus) NCIMB 40124. This new system overcomes some of the shortcomings of traditional Escherichia coli-based protein expression systems, particularly the propensity of such systems to form inclusion bodies during high-level expression. Using a proteomics approach, we identified promoters that can be induced by simple process parameters or medium compositions in high-density cell culture or shake flasks, respectively. By combining newly developed molecular biological tools with a high-cell-density fermentation process, we were able to produce high levels (>1 g/liter) of soluble, active organophosphohydrolase, a model enzyme prone to inclusion body formation in E. coli.

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