ABSTRACT
With the exception of a few species that are capable of autotrophic growth, clostridia lead a heterotrophic existence relying on organic molecules as a source of carbon and energy [1]. The acquisition of these molecules from the surrounding environment is a prerequisite for growth and development, and it is therefore unsurprising that specific mechanisms exist to catalyze and control their uptake. The majority of uptake, or transport, processes in bacteria utilize metabolic energy to enable concentration of the substrate in the cytoplasm at a level that can support metabolism. These active transport processes are classified according to the form of energy involved; either high-energy phosphate bonds (ATP or PEP) or ion gradients (H+ or Na+). Examples of each of these categories have been found in clostridia, and while the transport systems have in many cases not been characterized in detail, it is clear that clostridia employ typical bacterial mechanisms to support nutrient uptake. This chapter will review the current understanding of uptake of carbohydrates by clostridial species; strains that have been reclassified as members of the genera Thermoanaerobacter and Thermoanaerobacterium [2] have not been included.
