Production and characterization of a new bioemulsifier from Pseudomonas putida ML2.
OBJECTIVE
To characterize the bioemulsifier produced by a nonfluorescent strain of Pseudomonas putida isolated from a polluted sediment and to determine the influence of pH, temperature, media composition, and carbon and nitrogen source on growth and emulsifying activity.


RESULTS
Different indexes were employed to determine the emulsifying properties of culture supernatants of P. putida ML2 in defined and complex media. Surface tension of cell-free supernatants was measured. Purification and chemical analysis of the emulsifier was performed. Confirmed results indicate that a polysaccharide with hexasaccharide repeating units is responsible for the emulsifying activity in a mineral medium with glucose as sole carbon source. Moreover, an emulsifier is produced when growing on naphthalene.


CONCLUSIONS
Culture media composition influences the amount and the properties of the emulsifier produced by this P. putida strain. Under nitrogen limiting conditions, a polysaccharide is responsible for the emulsifying activity in defined mineral media. In complex nitrogen rich medium, a different kind of emulsifier is produced. The exopolymer may contribute to hydrocarbons solubilization.


CONCLUSIONS
This is the first exopolysaccharide with emulsifying properties produced by a Pseudomonas strain reported to the present. Also chemical composition is significantly different from previous reports. This strain has potential use in bioremediation and the purified polysaccharide may be used in food and cosmetic industry. Moreover, the production of the exopolymer may play a role on biofilm formation.
Bonilla
M
M
Department of Microbiology, School of Chemistry, Universidad de la Republica, Montevideo, Uruguay.
Olivaro
C
C
Corona
M
M
Vazquez
A
A
Soubes
M
M
D001431:Bacteriological Techniques; D045703:Emulsifying Agents; D005947:Glucose; D009281:Naphthalenes; D016958:Pseudomonas putida / Q000378:metabolism*; D012988:Soil Microbiology
D045703:Emulsifying Agents; D009281:Naphthalenes; C031721:naphthalene; D005947:Glucose