Isolation from coastal sea water and characterization of bacterial strains involved in non-ionic surfactant degradation

A bacterial community degrading branched alkylphenol ethoxylate (APE) was selected from coastal sea water intermittently polluted by urban sewage. This community degraded more than 99% of a standard surfactant, TRITON X 100, but I.R. analysis of the remaining compound showed the accumulation of APE(2) (alkylphenol with a two units length ethoxylated chain) which seemed very recalcitrant to further biodegradation. Twenty-five strains were isolated from this community, essentially Gram negative and were related to Pseudomonas, Oceanospirillum or Deleya genera. Among these strains, only four were able to degrade APE(9-10) (TRITON X 100). They were related to the Pseudomonas genus and were of marine origin. Pure cultures performed with these strains on TRITON X 100 gave APE(5) and APE(4) as end products. These products were further degraded to APE(2) by two other strains unable to degrade the initial surfactant.