Tuesday, May 1, 2012
Napoleon Ballroom C-D, 3rd fl (Sheraton New Orleans)
Consolidated bioprocessing has been shown to be an efficient approach for cellulosic biofuels and biochemicals production. An alternative method for the production of biobutanol from cellulosic biomass in a consolidated bioprocessing approach is the use of a clostridial co-culture. It has been demonstrated that the rate of cellulose utilization in the co-culture of Clostridium acetobutylicum and Clostridium cellulolyticum is improved compared to the mono-culture of C. cellulolyticum (Petitdemange et al., 1983), suggesting the presence of syntrophy between these two species. However, the phenotypic and metabolic behaviors of this co-culture are not well understood. Therefore, developing methods for the analysis of metabolism in this co-culture enables us to investigate the inter-species metabolic interactions for enhancing the metabolic rate and biobutanol synthesis.
Our experimental data showed 130% increase in the concentration of solubilized carbon (TOC) in the batch clostridial co-culture, compared to the mono-culture of C. cellulolyticum on cellulose. Further characterization of the co-culture metabolism using qPCR analysis showed that C. cellulolyticum growth rate is significantly higher in the co-culture compared to the mono-culture, verifying the hypothesis of syntrophic relationship between two species. These co-culture data would be useful for refining the previously developed co-culture model; since this model is not yet able to capture the growth arrest event at high cellulose concentrations.