Functional analysis of the thermophilic denitrifying bacterium Geobacillus sp. strain TDN01 in continuous culture

The thermophilic denitrifying bacterium Geobacillus sp. strain TDN01 was examined to determine the effects of nitrogen and carbon sources and nitrate and nitrite concentrations on denitrification in a batch culture. The specific nitrate removal rate was 12 times higher with ammonia than without ammonia. The consumption rates of nitrate and succinate were proportional. Furthermore, the growth rates with 120 and 150 mM nitrate were only slightly lower than those with 60 mM and did not cause notable growth inhibition. Denitrification ability in continuous culture was analyzed based on the data for batch culture. The maximum specific growth rate μ_max and substrate saturation constant K_S in the Monod equation were determined by gradually changing the dilution rate. The maximum denitrification rate was six times higher than that of mesophilic bacteria.