Chlorinated solvent bioremediation: A novel approach to measuring bacterial kinetics

A variety of anaerobic microorganisms can degrade perchloroethylene (PCE) in situ. Kinetic analyses of these cultures are required to determine the optimal growth conditions for remediation. It is difficult to supply PCE at the constant concentration required for kinetic analyses because of its volatility. Thus, a bioreactor with a bed of solid-phase sorbent Tenax was used to maintain steady-state concentrations of PCE in aqueous phase. Steady-state concentrations of PCE can be maintained for several months in halorespiring cultures using Tenax as a source. Tenax adsorbed the byproducts of dechlorination before they can accumulate to toxic levels. The microbial culture used was the anaerobic bacterial strain BB1, which gains energy by dechlorinating PCE to 1,2-cis-dichloroethene. The use of 1.0 mM radiolabeled acetate was a reliable approach for determining the growth rates of slow-growing anaerobes with low biomass concentrations over short time periods.