Journal of Zhejiang University SCIENCE
(ISSN 1009-3095, Monthly)

2005   Vol. 6B   No. 8   p.725-730

Biodegradation of crude oil by Pseudomonas aeruginosa in the presence of rhamnolipids

ZHANG Guo-liang^1,2, WU Yue-ting¹, QIAN Xin-ping¹, MENG Qin^†‡1

(¹School of Materials Science and Chemical Engineering, Zhejiang University, Hangzhou 310027, China)
(²Institute of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032, China)
^†E-mail: mengq@zju.edu.cn
Received Feb. 21, 2005; revision accepted Apr. 20, 2005

Abstract: The potential biodegradation of crude oil was assessed based on the development of a fermentative process with a strain of Pseudomonas aeruginosa which produced 15.4 g/L rhamnolipids when cultured in a basal mineral medium using glycerol as a sole carbon source. However, neither cell growth nor rhamnolipid production was observed in the comparative culture system using crude oil as the sole carbon source instead. As rhamnolipid, an effective biosurfactant, has been reported to stimulate the biodegradation of hydrocarbons, 1 g/L glycerol or 0.22 g/L rhamnolipid was initially added into the medium to facilitate the biodegradation of crude oil. In both situations, more than 58% of crude oil was degraded and further converted into accumulated cell biomass and rhamnolipids. These results suggest that Pseudomonas aeruginosa could degrade most of crude oil with direct or indirect addition of rhamnolipid. And this conclusion was further supported by another adsorption experiment, where the adsorption capacity of crude oil by killed cell biomass was negligible in comparison with the biologic activities of live cell biomass.

Key words: Rhamnolipid, Crude oil, Biodegradation, Pseudomonas aeruginosa
doi:10.1631/jzus.2005.B0725             CLC number: TQ658

^‡ Corresponding Author