title: Manipulation of the acetylation degree of Azotobacter vinelandii alginate by supplementing the culture medium with 3-(N-morpholino)-propane-sulfonic acid.
abstract: OBJECTIVE
  The aim of this study was to characterize the influence of 3-(N-morpholino)-propane-sulfonic acid (MOPS) on alginate production by Azotobacter vinelandii and its chemical composition (particularly its acetylation degree), as well as on the rheological behaviour of alginate-reconstituted solutions.
  
  
  RESULTS
  Cultures were grown in 500-ml flasks containing 90 ml of medium supplemented with MOPS in concentrations ranging from 0 to 13.6 mmol l(-1). The acetylation degree of the alginate was significantly influenced by the MOPS concentration, obtaining an alginate with an acetylation degree of 1.4% when 13.6 mmol l(-1) of MOPS was added to the medium. This value was twice as high as that obtained when no MOPS was used. The higher acetylation of the polymer resulted in higher viscosity of alginate solutions, having a more pronounced pseudoplastic behaviour.
  
  
  CONCLUSIONS
  MOPS added to the culture medium determines the acetyl content of the alginate and thus, the physico-chemical properties of the polymer.
  
  
  CONCLUSIONS
  These changes in the functional properties of the polymer can be very valuable in specific applications of alginate in the food and pharmaceutical fields.
authors.affiliation: Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Morelos. carlosf@ibt.unam.mx
authors.forename: C
authors.initials: C
authors.lastname: Peña
authors.forename: L
authors.initials: L
authors.lastname: Hernández
authors.forename: E
authors.initials: E
authors.lastname: Galindo
mesh_terms: D000107:Acetylation; D000464:Alginates / Q000737:chemistry* / Q000302:isolation & purification; D016948:Azotobacter vinelandii / Q000737:chemistry* / Q000378:metabolism; D003470:Culture Media; D020723:Glucuronic Acid / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification; D006603:Hexuronic Acids / Q000737:chemistry / Q000302:isolation & purification; D009025:Morpholines / Q000378:metabolism*; D014783:Viscosity
chemical_list: D000464:Alginates; D003470:Culture Media; D006603:Hexuronic Acids; D009025:Morpholines; C008550:morpholinopropane sulfonic acid; D020723:Glucuronic Acid