Pyruvate Carboxylase Of Rhizopus Nigricans And Its Role In Fumaric Acid Production

The chief carbon dioxide-fixing system in a fumaric acid-producing strain of Rhizopus nigricans is an acetyl coenzyme A - dependent pyruvate carboxylase. This enzyme is produced in high levels during the period of rapid glucose utilization, and precedes fumarate accumulation. It is proposed that this system is the principal anaplerotic CO 2 fixing mechanism in this organism, and its continued operation in high glucose media after biosynthesis has ceased results in production of fumaric acid.