(257f) Evaluating the Potential of Using the Thermophilic Bacterium Thermus Thermophilus for Biofuels Production

Thermus thermophilus is a thermophilic eubacterium that thrives at temperatures above 80°C. In this presentation, we will demonstrate the potential of using T. thermophilus for the production of volatile biofuels. T. thermophilus has a high growth rate (i.e. 0.55 1/hr on defined medium, and 0.95 1/hr on complex medium), high biomass yield (similar to E. coli), and shows high transformation competence making it amendable to genetic manipulations. A current bottleneck for biotechnological applications of T. thermophilus is the limited knowledge regarding its metabolism and growth characteristics. In this work, we reconstructed and validated the metabolic network model of T. thermophilus HB8 using ¹³C tracer experiments and characterized its metabolism using ¹³C-metabolic flux analysis (MFA). T. thermophilus HB8 was successfully grown in custom-designed mini-bioreactors (10 mL) on optimized minimal medium without yeast extract. A large scale metabolic network model was first extracted from KEGG and then validated using parallel labeling experiments with ¹³C-glucose tracers. For each tracer experiment we measured the labeling of amino acids (using GC-MS) and the labeling of CO₂ (using an on-line mass spectrometer). Metabolic fluxes were determined by fitting the measured isotopomer data to the reconstructed metabolic model. After validating the model, we performed tolerance studies to evaluate the potential of using T. thermophilus for the production of biofuels, including short chain alcohols such as ethanol, propanol, n-butanol, and isobutanol. Our results that strongly support the biotechnological potential of this organism for efficient biofuels production at high temperatures.