PREDOMINANCE OF YET UNCULTURED GAMMA- PROTEOBACTERIA IN NONYLPHENOL ETHOXYLATE-ENRICHED ACTIVATED SLUDGE

EVA L. M. FIGUEROLA; RAÚL F. ITRIA; MARIANA LOZADA; LEONARDO ERIJMAN

Bariloche, Argentina

Congreso; XXXIX Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2003

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

PREDOMINANCE OF YET UNCULTURED GAMMA- PROTEOBACTERIA IN NONYLPHENOL ETHOXYLATE-ENRICHED ACTIVATED SLUDGE Figuerola, Eva L.; Itria, Raúl F.; Lozada, Mariana; Erijman, Leonardo. INGEBI-CONICET, Buenos Aires, Argentina. E-mail: figuerola@dna.uba.ar Surfactants are among the most common organic contaminants in wastewater. Some of these surfactants, particularly nonylphenol ethoxylates, and their metabolites have been implicated as ´environmental estrogens´ that affect fertility in animals and humans. Two libraries were constructed with amplified full-length insert 16S rDNA from reactors fed with synthetic effluent plus nonylphenol ethoxylate (NPEO) and two of unamended controls. A total of 187 clones were digested with restriction enzymes RsaI and HhaI. Changes of relative diversities under different treatment regimens, i.e. presence or absence of NPEO in the feeding solution, within otherwise identical environments, were taken as representative of qualitative changes in the microbial community. NPEO had a significant effect in the increase in relative abundance of a few RFLP patterns compared to control libraries. The sequences of several clones corresponding to the dominant phylotype in libraries from reactors treated with NPEO (ca. 35% of total clones in each replicate reactor) were assigned to uncultivated gamma-proteobacteria subclass, suggesting the involvement of this group in NPEO degradation. Two new specific rRNA-targeted oligonucleotide probes were designed from our five 16S rDNA sequences and four other sequences retrieved from public databases of closely related environmental clones. Real time PCR using UNG1026 and UNG1228 demonstrated the applicability of the probes to monitoring the abundance of these so far uncultured species in natural and engineered environments.