How do obligate anaerobes, like the bacteria c. botulinum, get energy?

It ferments.

Explanation:

This bacteria ferments glycine, proline, phenylaline, and leucine. The remaining energy is obtained by sugar metabolism.

enzyme active site and substrate specificity

enzymes bind with chemical reactants called substrates. there may be one or more substrates for each type of enzyme, depending on the particular chemical reaction. in some reactions, a single-reactant substrate is broken down into multiple products