Research Product

The effects of bioaugmentation on the aerobic cometabolism of trichloroethylene (TCE) in groundwater were investigated using small-column aquifer microcosms. Nonsterile nonbioaugmented microcosms fed phenol as a primary substrate mimicked observed in-situ behavior at the Moffett Field site (1), cometabolizing approximately 60 ug/L TCE while fed 6.5 mg/L phenol. High-density single bioaugmentation with Burkholderia (Pseudomonas) cepacia G4 increased TCE removal in sterile aquifer material, while producing mixed results in nonsterile material. Low-density semicontinuous bioaugmentation enhanced TCE transformation in nonsterile microcosms. A nonrecombinant NTG-induced mutant of G4 (PR1 301) capable of uninduced constitutive degradation of TCE in the absence of phenol or toluene was developed for environmental release. Phenol-fed microcosms augmented with either B. cepacia strain G4 or PR1 301 transformed twice as much TCE as the nonaugmented phenol-fed microcosm. In addition, should primary substrate addition be a regulatory concern, TCE degradation was observed without primary substrate addition through bioaugmentation using organisms expressing the TCE-transforming enzyme.