THE EFFECT OF INCUBATION-TEMPERATURE ON STEADY-STATE CONCENTRATIONS OF HYDROGEN AND VOLATILE FATTY-ACIDS DURING ANAEROBIC DEGRADATION IN SLURRIES FROM WETLAND SEDIMENTS

Increasing the incubation temperature of two swamp slurries from 2 deg rees C to 37 degrees C resulted in a 8- to 18-fold increase in the H-2 partial pressure. The concentration of volatile fatty acids remained fairly constant except for butyrate, which decreased with increasing t emperature. Calculation of Gibbs free energies of syntrophic degradati on of butyrate and propionate, and of methanogenesis from acetate and H-2 revealed that these reactions were exergonic after the slurries ha d stabilized at the incubation temperatures. The changes in H-2 partia l pressure and butyrate concentration with temperature were found impo rtant to render the processes exergonic within the tested temperature range.