IDENTIFICATION OF DOMINANT BACTERIAL POPULATIONS IN NONYLPHENOL POLYETHOXYLATE DEGRADING ACTIVATED SLUDGE

LOZADA, MARIANA; FIGUEROLA, EVA; ITRIA, RAÚL F.; ERIJMAN, L.

Pinamar, Argentina

Congreso; XLI Annual Meeting of the Argentine Society for Biochemistry and Molecular Biology (SAIB 2005); 2005

Sociedad Argentina de Investigaciones Bioquímicas

We have analyzed bacterial communities associated with nonylphenol polyethoxylate (NPE) biodegradation in laboratory scale activated sludge. Four replicate lab-scale reactors were built and operated in a fill-and-draw mode, showing stable performance for a period of 21 months. All four reactors were fed with synthetic sewage, and two of them received additionally 1% NPE. The marked differences observed between treated and control reactors in NPE degradation capabilities suggested the existence of a microbial community specialized in surfactant degradation. The dynamics of the bacterial community in the reactors sludge was analyzed using nonparametric multivariate statistical analysis and diversity analysis. The clustering of NPE treated replicate reactors at similar times and the decrease in diversity in NPE treated reactors suggested the community changes were driven by a succession process consisting of the selection and establishment of dominant populations specialized in NPE degradation. Using culture independent molecular methods (ribosomal RNA genes amplification, DGGE, library construction, cloning with specific primers, membrane rRNA hybridization,fluorescence in situ hybridization and real time PCR) we identified and quantified these dominant bacterial populations associated with long term exposure to NPE in the treated reactors.