Kinetics of sulfur oxidation at suboptimal temperatures.

Chemolithoautotrophic bacteria were enriched from mine water at incubation temperatures ranging from 4 to 46 degrees C, using elemental sulfur as a substrate in acid mineral salts media. Thiobacillus-type bacteria were successfully enriched for at all test temperatures except 46 degrees C. Changes in pH (-dpH/dt) were used to estimate the rate constants for the enrichment cultures. The rate constants yielded a linear Arrhenius plot, an activation energy of 65 kJ/mol, and a temperature coefficient (Q(10)) of 2.1 for the 4 to 37 degrees C temperature interval.