Effect of temperature, pH and electron donor on the microbial reductive dechlorination of chloroalkenes

In order to elucidate the effect of environmental conditions such as pH, temperature, and electron donor on the microbial reductive dechlorination of tetrachloroethylene and its transformation products, batch, acetate-fed methanogenic cultures were developed from a field contaminated soil and incubated within a pH range of 4 to 9.5 and a temperature range of 5 to 45°C. Optimum conditions for reductive dechlorination were achieved at pH and temperature values of around 7 and 35°C, respectively. Methane production was more affected by pH and temperature than was the rate of dechlorination. Increased levels of electron donor (acetate) resulted in faster rates of both methanogenesis and reductive dechlorination. The effect of pH and temperature on the dechlorination rate and methane production were simulated by using previously established relationships pertaining to the activation and deactivation of enzymatic processes.