Aerobic Degradation of 3-Methylindole by Pseudomonas aeruginosa Gs Isolated from Mangrove Sediment

ABSTRACT

3-Methylindole (3MI), an N-heterocyclic aromatic compound also called skatole, is associated with animal waste and industrial processing. A pure culture of bacterium capable of using 3MI as the sole source of carbon and energy was isolated from mangrove sediment using an enrichment technique and identified as Pseudomonas aeruginosa Gs based on 16S rDNA sequence. Microbial degradation of 3MI was studied in batch culture experiments for several factors, including initial substrate concentrations, pH, and salinity. The optimum pH and salinity was 7.0 and 5‰, respectively. Degradation of 3MI by P. aeruginosa Gs was quantified by reversed-phase high-performance liquid chromatography. Two metabolites of 3MI degradation were detected and proposed to be indoline-3-carboxylic acid and indoline-3-ol based on data obtained from HPLC/MS. Our results suggest that 3MI can be rapidly degraded by indigenous microorganisms found in mangrove sediment.

Key Words:

• aerobic
• biochemical pathway
• biodegradation
• mangrove
• metabolites
• 3-methylindole.

ACKNOWLEDGMENTS

This research was supported by the Chinese Academy of Sciences, “863 Project” No. 2002AA601160, and SCSIO project no. LYQY200306. We thank Pan Li for the determination of the 16S rDNA of the bacterial isolates.