Abstract
Surface-active compounds (SACs) are widely used in different industries as well as in many daily
consumption products. However, with the increasing concern for their environmental
acceptability, attention has turned towards biological SACs which are biodegradable, less toxic
and more environmentally friendly. In this work, 176 marine hydrocarbon-degrading bacterial
isolates from petroleum-contaminated sites along the Norwegian coastline were isolated and
screened for their capacity to produce biological SACs. Among them, 18 isolates were capable of
reducing the surface tension of the culture medium by at least 20 mN m−1 and/or capable of
maintaining more than 40% of the emulsion volume after 24 h when growing on glucose or
kerosene as carbon and energy source. These isolates were members of the genera
Pseudomonas, Pseudoalteromonas, Rhodococcus, Catenovulum, Cobetia, Glaciecola, Serratia,
Marinomonas and Psychromonas. Two isolates, Rhodococcus sp. LF-13 and Rhodococcus sp. LF-22,
reduced surface tension of culture medium by more than 40 mN m−1 when growing on
kerosene, n-hexadecane or rapeseed oil. The biosurfactants were produced by resting cells of the
two Rhodococcus strains suggesting the biosynthesis of the biosurfactants was not necessarily
associated with their growth on hydrocarbons.
consumption products. However, with the increasing concern for their environmental
acceptability, attention has turned towards biological SACs which are biodegradable, less toxic
and more environmentally friendly. In this work, 176 marine hydrocarbon-degrading bacterial
isolates from petroleum-contaminated sites along the Norwegian coastline were isolated and
screened for their capacity to produce biological SACs. Among them, 18 isolates were capable of
reducing the surface tension of the culture medium by at least 20 mN m−1 and/or capable of
maintaining more than 40% of the emulsion volume after 24 h when growing on glucose or
kerosene as carbon and energy source. These isolates were members of the genera
Pseudomonas, Pseudoalteromonas, Rhodococcus, Catenovulum, Cobetia, Glaciecola, Serratia,
Marinomonas and Psychromonas. Two isolates, Rhodococcus sp. LF-13 and Rhodococcus sp. LF-22,
reduced surface tension of culture medium by more than 40 mN m−1 when growing on
kerosene, n-hexadecane or rapeseed oil. The biosurfactants were produced by resting cells of the
two Rhodococcus strains suggesting the biosynthesis of the biosurfactants was not necessarily
associated with their growth on hydrocarbons.