(624b) Effect of Carbonyl Inhibitors on the Intracellular Metabolism in Microbial Fermentation

Carbonyl inhibitors from biomass prehydrolysates could dramatically decrease the cell growth and fermentation rate, however, the knowledge of the inhibitory mechanism of cell metabolism and biofuel production is still insufficient, especially for phenolic aldehydes and ketones. Hence, a comparative study of the primary intermediate metabolites will be critical to understand the inhibition mechanism and improve the fermentation performance. In this study, the effect of carbonyl inhibitors (such as, furfural, 2,3-dihydroxybenzaldehyde and cinnamaldehyde) on Saccharomyces cerevisiae and Clostridium saccharobutylicum metabolome were investigated. It was observed that the carbonyl inhibitors significantly decreased the intracellular glucose and ethanol concentration in yeast fermentation, although the final ethanol production was promoted with low concentration of cinnamaldehyde. Besides, the glycerol production was also limited for both intracellular and extracellular metabolism. Interestingly, the addition of carbonyl inhibitors increased the extracellular acetic acid, while the intracellular acetic acid production was decreased. Furthermore, nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry will be employed to further illustrate the response of intracellular metabolites (such as, nucleotides, fatty acids and amino acids) to the carbonyl inhibitors. In addition, the bioconversion of the supplemented inhibitors during microbial fermentation will be determined to evaluate the in-situ detoxification ability of the microorganisms. Changes of intracellular metabolic activity in presence of inhibitors will provide a comprehensive understanding of inhibitory effects on cell metabolism during the fermentation process. This would be a significant step towards the improvement of prehydrolysate fermentability for solvent production.