Effect of Tryptone and Tungsten in Medium on Syngas Fermentation Using Clostridium ljundahlii

In this study, an experiment was conducted to investigate the effect of the concentrations of tryptone, an organic nitrogen supplement, and sodium tungstate on the growth of microbial and the production of acetic acid and ethanol in the culture of Clostridium ljungdahlii. Microbial growth increased by 144.6%, and ethanol and acetic acid production improved by 8.6% and 36.7%, respectively, when 2.5 g/L of tryptone was added to the medium of the control experiment (0 g/L tryptone). In the experiment with 1 & mu;M Na2WO4 & BULL;2H2O, which is 100 times higher than the condition of the medium used in the control experiment (0.01 & mu;M Na2WO4 & BULL;2H2O), there was no significant difference in microbial growth or total production of C2 metabolites, but ethanol production increased and acetic acid production decreased. As a result, the ethanol/acetic acid production ratio increased significantly from 0.24 in the control experiment to 0.56.