Effect of cations, pH and sulfate content on the viscosity and emulsifying activity of the Halomonas eurihalina exopolysaccharide

  • C Calvo
  • F Martinez-Checa
  • A Mota
  • V Bejar
  • E Quesada

DOI: 10.1038/sj.jim.2900513

Cite this article as:
Calvo, C., Martinez-Checa, F., Mota, A. et al. J Ind Microbiol Biotech (1998) 20: 205. doi:10.1038/sj.jim.2900513

The effects of monovalent and divalent cations on the rheological behavior of Halomonas eurihalina exopolysaccharide (EPS) were studied. Sodium, potassium, magnesium and calcium were added and the relative abilities to increase viscosity were as follows: KCl > NaCl > MgCl2 > CaCl2. The highest viscosity value was measured in acidic 10−4 M KCl, in which a gel formed. A loss of sulfate content seemed to correlate with the increase of viscosity. H. eurihalina produced EPS in all growth media. Addition of hydrophobic substrates to culture media produced changes in chemical composition and emulsifying activity of the EPS. Xylene was the most effectively emulsified substance and the EPS produced on tetradecane and on corn oil the most active emulsifier.

Keywords: exopolysaccharide; rheology; emulsifier

Copyright information

© Society for Industrial Microbiology 1998

Authors and Affiliations

  • C Calvo
    • 1
  • F Martinez-Checa
    • 2
  • A Mota
    • 1
  • V Bejar
    • 2
  • E Quesada
    • 2
  1. 1.Water Institute, Faculty of Pharmacy, University of Granada 18071, SpainES
  2. 2.Department of Microbiology, Faculty of Pharmacy, University of Granada 18071, SpainES