PREDOMINANT UNCULTURED BACTERIA IN ACTIVATED SLUDGE TREATING SURFACTANT RICH WASTEWATER DETERMINED BY DENATURING GRADIENT GEL ELECTROPHORESIS

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

Florianopolis, Brasil

Congreso; XXII Congresso Brasileiro de Microbiologia; 2003

Asociacion Brasilera de Microbiologia

Due to their extended range of applications, non-ionic surfactants represent a significant contribution to organic pollution in the aquatic environment. Some of these surfactants, particularly nonylphenol ethoxylates (NPEO),and their metabolites have been implicated as ´environmental estrogens´ that affect fertility in animals and humans. Denaturing gradient gel electrophoresis (DGGE) was used to monitor the impact of NPEO on microbial community dynamics in lab-scale activated sludge. Biomass from an industrial activated sludge was adapted to lab conditions and split into tour activated sludge reactors, fed with synthetic effluent with or without NPEO (two replicate reactors for each treatment). After direct DNA extraction, PCR amplification of whole eubacterial community DNA were performed with universal primers that bracketed a hypervaríable regions of the 16S rDNA gene sequences, yielding PCR products of about 410 bp, which were separated by DGGE. Common dominant bands to both treated reactors and absent from unamended controls were excised from the gel. Following reamplification, PCR products were analyzed by DGGE to confirm their electrophoretic mobility relative to the fragment from which they were excised, and cloned. Cloned sequences turned out to yield a single sequence, which was phylogenetically not associated with any recognized genus, but was most closely related to uncultured environmental sequences. Bacteria belonged to hitherto unknown genera have not been implicated before in the degradation of NPEO.