CHARACTERIZATION OF FILAMENTOUS FOAMING IN ACTIVATED-SLUDGE SYSTEMS USING OLIGONUCLEOTIDE HYBRIDIZATION PROBES AND ANTIBODY PROBES

A quantitative method was developed for estimating Gordona mass in act ivated sludge foam and mixed liquor samples. The technique involves in situ hybridization with a genus-specific fluorescently labeled oligon ucleotide probe calibrated on pure cultures of Gordona. The immunofluo rescent technique of Hernandez et al. was modified to allow staining w ith fluorescently labeled antibody and hybridization probes. The resul ts of this technique were compared to those From membrane hybridizatio n studies using radioactively-labeled oligonucleotide probes. Quantita tive membrane hybridizations, in situ hybridizations, and antibody sta ining resulted in significantly different levels of Gordona in activat ed sludge foam, activated sludge mixed liquor, return activated sludge , and anaerobic digester sludge. Simultaneous staining with labeled an tibodies and oligonucleotide probes provide a definitive identificatio n for Gordona, and represents a new approach for in situ studies of th is organism's role in foaming. (C) 1998 IAWQ. Published by Elsevier Sc ience Ltd.