Abstract
Gellan gum is a new bacterial polysaccharide exhibiting interesting properties. This study deals with the effect of fermentor hydrodynamics on production, physico-chemical characteristics and potentialities of this biopolymer in non polluting well drilling fluids. The crucial role of oxygen transfer on gellan production was clearly shown by fermentations carried out with three impeller systems generating different macromixing patterns, or with nitrogen limitation or extra oxygen supply. In addition, understanding of the physiology of gellan synthesis was improved. Furthermore, the more homogeneous the macromixing conditions, the higher the molecular weight of the polysaccharide. Besides, no effect of oxygen transfer on gellan molecular weight was observed whereas oxygen limited conditions led to an increase of the esterification degree of the polymer. Finally, native gellan gum displayed thixotropic and fluid loss control properties and thereby seems to be a very interesting polymer for water-based well drilling fluids. For this application, performances obtained with gellan are similar to those of the widely used semi-synthetic polymer CMC. Moreover, gellan was less sensitive to the presence of divalent cations and led to more thixotropic fluids.
Citation Formats
Dreveton, E.
Gellan: Influence of the fermentor hydrodynamics on its production, its physico-chemical characteristics and its possibilities of appliance in drilling fluids.
France: N. p.,
1994.
Web.
Dreveton, E.
Gellan: Influence of the fermentor hydrodynamics on its production, its physico-chemical characteristics and its possibilities of appliance in drilling fluids.
France.
Dreveton, E.
1994.
"Gellan: Influence of the fermentor hydrodynamics on its production, its physico-chemical characteristics and its possibilities of appliance in drilling fluids."
France.
@misc{etde_10155913,
title = {Gellan: Influence of the fermentor hydrodynamics on its production, its physico-chemical characteristics and its possibilities of appliance in drilling fluids}
author = {Dreveton, E}
abstractNote = {Gellan gum is a new bacterial polysaccharide exhibiting interesting properties. This study deals with the effect of fermentor hydrodynamics on production, physico-chemical characteristics and potentialities of this biopolymer in non polluting well drilling fluids. The crucial role of oxygen transfer on gellan production was clearly shown by fermentations carried out with three impeller systems generating different macromixing patterns, or with nitrogen limitation or extra oxygen supply. In addition, understanding of the physiology of gellan synthesis was improved. Furthermore, the more homogeneous the macromixing conditions, the higher the molecular weight of the polysaccharide. Besides, no effect of oxygen transfer on gellan molecular weight was observed whereas oxygen limited conditions led to an increase of the esterification degree of the polymer. Finally, native gellan gum displayed thixotropic and fluid loss control properties and thereby seems to be a very interesting polymer for water-based well drilling fluids. For this application, performances obtained with gellan are similar to those of the widely used semi-synthetic polymer CMC. Moreover, gellan was less sensitive to the presence of divalent cations and led to more thixotropic fluids.}
place = {France}
year = {1994}
month = {Jan}
}
title = {Gellan: Influence of the fermentor hydrodynamics on its production, its physico-chemical characteristics and its possibilities of appliance in drilling fluids}
author = {Dreveton, E}
abstractNote = {Gellan gum is a new bacterial polysaccharide exhibiting interesting properties. This study deals with the effect of fermentor hydrodynamics on production, physico-chemical characteristics and potentialities of this biopolymer in non polluting well drilling fluids. The crucial role of oxygen transfer on gellan production was clearly shown by fermentations carried out with three impeller systems generating different macromixing patterns, or with nitrogen limitation or extra oxygen supply. In addition, understanding of the physiology of gellan synthesis was improved. Furthermore, the more homogeneous the macromixing conditions, the higher the molecular weight of the polysaccharide. Besides, no effect of oxygen transfer on gellan molecular weight was observed whereas oxygen limited conditions led to an increase of the esterification degree of the polymer. Finally, native gellan gum displayed thixotropic and fluid loss control properties and thereby seems to be a very interesting polymer for water-based well drilling fluids. For this application, performances obtained with gellan are similar to those of the widely used semi-synthetic polymer CMC. Moreover, gellan was less sensitive to the presence of divalent cations and led to more thixotropic fluids.}
place = {France}
year = {1994}
month = {Jan}
}