Enhancement of solubilization and biodegradation of polyaromatic hydrocarbons by the bioemulsifier alasan

T. Barkay*, S. Navon-Venezia, E. Z. Ron, E. Rosenberg

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Alasan, a high-molecular-weight bioemulsifier complex of an anionic polysaccharide and proteins that is produced by Acinetobacter radioresistens KA53 (S. Navon-Venezia, Z. Zosim, A Gottlieb, R. Legmann, S. Carmeli, E. Z. Ron, and E. Rosenberg, Appl. Environ, Microbiol. 61:3240-3244, 1995), enhanced the aqueous solubility and biodegradation rates of polyaromatic hydrocarbons (PAHs). In the presence of 500 μg of alasan ml-1, the apparent aqueous solubilities of phenanthrene, fluoranthene, and pyrene were increased 6.6-, 25.7-, and 19.8-fold, respectively. Physicochemical characterization of the solubilization activity suggested that alasan solubilizes PAHs by a physical interaction, most likely of a hydrophobic nature, and that this interaction is slowly reversible. Moreover, the increase in apparent aqueous solubility of PAHs does not depend on the conformation of alasan and is not affected by the formation of multimolecular aggregates of alasan above its saturation concentration. The presence of alasan more than doubled the rate of [14C]fluoranthene mineralization and significantly increased the rate of [14C]phenanthrene mineralization by Sphingomonas paucimobilis EPA505. The results suggest that alasan-enhanced solubility of hydrophobic compounds has potential applications in bioremediation.

Original languageEnglish
Pages (from-to)2697-2702
Number of pages6
JournalApplied and Environmental Microbiology
Volume65
Issue number6
DOIs
StatePublished - Jun 1999

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