More Heat than Light: Opportunities for Extremely Thermophilic Microorganisms and Enzymes in Biofuels

The recent interest in biofuels has motivated a closer look at microorganisms from extremely high temperature environments, not only for their capacity to deconstruct the carbohydrate content of plant biomass but also for novel metabolic pathways harbored in their genomes that could facilitate critical biotransformations. Our laboratory has used a systems biology approach to examine the microbial physiology of extreme thermophiles for clues to novel biocatalysts and metabolic features that are relevant to improved biofuels production.

Discussed here will be opportunities for biofuels that relate to extremely thermophilic microorganisms. The genus Caldicellulosiruptor contains extremely thermophilic bacteria, and includes species that produce primary cellulases, which degrade plant biomass to fermentable sugars. The growth physiology and microbial biochemistry of these bacteria suggest that these bacteria could play an important role in the production of 2nd generation biofuels. A longer-term goal is to produce biofuels directly from CO2, thus by-passing photosynthetic processes. Possible directions along these lines that implicate metabolic pathways in extremely thermophilic archaea will be considered.