Modeling kinetics of chloroform cometabolism in methanogenic and sulfate-reducing environments

The kinetics of chloroform cometabolism in methanogenic and sulfate-reducing environments were modeled. Chloroform inhibits acetate utilization in methanogenic environments and therefore the rate of chloroform cometabolism was modeled using two terms: cometabolism due to primary substrate utilization and cometabolism due to microbial cell decay (no primary substrate utilization). The modified Haldane equation was used to model chloroform cometabolism due to primary substrate utilization and the Monod equation was used for the cometabolism due to microbial cell decay. A commercial software, SigmaPlot (Jandel Scientific Software) was used to determine the optimum parameters for the model. The model agreed very well with the experimental results. The model parameters confirmed that the sulfate-reducing culture has a very high potential for chloroform cometabolism compared to the methanogenic cultures. Also, the methanogenic culture grown on acetate is very sensitive to chloroform compared to the methanogenic culture grown on methanol.