Applied Microbiology and Biotechnology

, 72:132

Rhamnolipid production by a novel thermophilic hydrocarbon-degrading Pseudomonas aeruginosa AP02-1

  • Amedea Perfumo
  • Ibrahim M. Banat
  • Francesco Canganella
  • Roger Marchant
Applied Microbial and Cell Physiology

DOI: 10.1007/s00253-005-0234-0

Cite this article as:
Perfumo, A., Banat, I.M., Canganella, F. et al. Appl Microbiol Biotechnol (2006) 72: 132. doi:10.1007/s00253-005-0234-0

Abstract

Thermophilic bacterial cultures were isolated from a hot spring environment on hydrocarbon containing mineral salts media. One strain identified as Pseudomonas aeruginosa AP02-1 was tested for the ability to utilize a range of hydrocarbons both n-alkanes and polycyclic aromatic hydrocarbons as sole carbon source. Strain AP02-1 had an optimum growth temperature of 45°C and degraded 99% of crude oil 1% (v/v) and diesel oil 2% (v/v) when added to a basal mineral medium within 7 days of incubation. Surface activity measurements indicated that biosurfactants, mainly glycolipid in nature, were produced during the microbial growth on hydrocarbons as well as on both water-soluble and insoluble substrates. Mass spectrometry analysis showed different types of rhamnolipid production depending on the carbon substrate and culture conditions. Grown on glycerol, P. aeruginosa AP02-1 produced a mixture of ten rhamnolipid homologues, of which Rha-Rha-C10-C10 and Rha-C10-C10 were predominant. Rhamnolipid-containing culture broths reduced the surface tension to ≈28 mN and gave stable emulsions with a number of hydrocarbons and remained effective after sterilization. Microscopic observations of the emulsions suggested that hydrophobic cells acted as emulsion-stabilizing agents.

Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  • Amedea Perfumo
    • 1
    • 2
  • Ibrahim M. Banat
    • 2
  • Francesco Canganella
    • 1
  • Roger Marchant
    • 2
  1. 1.Department of Agrobiology and AgrochemistryUniversity of TusciaViterboItaly
  2. 2.Microbial Biotechnology Group, School of Biomedical SciencesUniversity of UlsterColeraineUK