Direct immunofluorescence and enzyme-linked immunosorbent assays for evaluating organic contaminant degrading bacteria

Abstract

Immunological procedures were developed to enumerate chlorinated hydrocarbon (CH) degrading bacteria in environmental samples. Polyclonal antibodies (Pabs) were produced by immunizing New Zealand white rabbits against 18 CH-degrading bacteria. These bacteria included methanotrophic and chlorobenzene (CB)-degrading species. An enzyme-linked immunosorbent assay (ELISA) was used to test for cross-reactivity and sensitivity of the Pabs. Direct fluorescent antibodies (DFAs) were developed against selected methanotrophic bacteria isolated from a trichloroethylene (TCE)-contaminated landfill at the Savannah River Site (SRS) and cultures from the American Type Culture Collection (ATCC). Analysis of ELISA results showed some of the Pabs to be group specific while others were species specific. The threshold of sensitivity for the ELISA is 10 5 bacteria cells/ml. Results from the DFA and ELISA techniques for enumeration of methanotrophic bacteria in groundwater were higher but not significantly different ( P<0.05) compared to indirect microbiological techniques such as MPN, although the direct enumerations were accomplished in significantly less time. These methods provide important information on in situ microbial community structure and function for bioremediation applications within 1–4 h of sampling.