Temperature Compensation in Methanosarcina barkeri by Modulation of Hydrogen and Acetate Affinity

The affinity of Methanosarcina barkeri 227 for acetate and hydrogen at different incubation temperatures was investigated. Increasing the temperature from 20 to 37°C resulted in a 4.5-fold increase in K_m for acetate and a 4.8-fold increase for hydrogen. The corresponding increase in V_max for acetate was 8.3-fold (5.4-fold for hydrogen). This response implied a decrease in the temperature coefficient (Q₁₀) and hence a decrease in the temperature dependency as a function of decreasing substrate concentration.