Abstract
Agromonas oligotrophica is an oligotrophic, dinitrogen-fixing soil bacterium which is found to grow on ferulic acid.This study aimed to characterize in more detail the growth of A.oligotrophica on ferulate and the degradation of ferulate.Ten- and 100-fold dilutions of conventional nutrient broth(NB/10 and NB/100, respectively) and yeast extract-supplemented mineral salts(MS) media were used for the batch growth experiments.In these media, the initial growth of A.oligotrophica was suppressed by ferulate in a dose-dependent manner.However, the cell biomass formed in the cultures was positively correlated with the amounts of ferulate used at ferulate concentrations between 0 and 5mM, indicating that ferulate was the growth-limiting nutrient under the conditions.Thus, the growth yield on ferulate was calculated to be 59-67g dry weight(mol ferulate)-1 in the NB/10 and the yeast extract-supplemented MS cultures, while in the NB/100 cultures a lower value [33g dry weight(mol ferulate)-1] was obtained.In a resting cell experiment with ferulate, vanillate was identified by high performance liquid chromatography and the degradation pathway was expected to be analogous to the well-known pathway which includes vanillate and protocatechuate as intermediates.
