Effect of emulsan on biodegradation of crude oil by pure and mixed bacterial cultures

J. M. Foght, D. L. Gutnick, D. W.S. Westlake

Research output: Contribution to journalArticlepeer-review


Crude oil was treated with purified emulsan, the heteropolysaccharide bioemulsifier produced by Acinetobacter calcoaceticus RAG-1. A mixed bacterial population as well as nine different pure cultures isolated from various sources was tested for biodegradation of emulsan-treated and untreated crude oil. Biodegradation was measured both quantitatively and qualitatively. Recovery of 14CO2 from mineralized 14C-labeled substrates yielded quantitative data on degradation of specific compounds, and capillary gas chromatography of residual unlabeled oil yielded qualitative data on a broad spectrum of crude oil components. Biodegradation of linear alkanes and other saturated hydrocarbons, both by pure cultures and by the mixed population, was reduced some 50 to 90% after emulsan pretreatment. In addition, degradation of aromatic compounds by the mixed population was reduced some 90% in emulsan-treated oil. In sharp contrast, aromatic biodegradation by pure cultures was either unaffected or slightly stimulated by emulsification of the oil.

Original languageEnglish
Pages (from-to)36-42
Number of pages7
JournalApplied and Environmental Microbiology
Issue number1
StatePublished - 1989
Externally publishedYes


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