Effect of emulsan on biodegradation of crude oil by pure and mixed bacterial cultures.
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 CO(2) from mineralized C-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.
Foght
J M
JM
Department of Microbiology, University of Alberta, Edmonton, Alberta, Canada T6G 2E9, and Department of Microbiology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv 69978, Israel.
Gutnick
D L
DL
Westlake
D W
DW