Carbon dioxide fixation into amino acids of penicillium chrysogenum.

The relation of CO2 to the metabolism of Penicillium chrysogenum has been studied in three ways in this work: (1) attempts were made to replace C02; (2) radioactive C1402 was used to determine the conditions under which CO2 fixation occurred; and (3) attempts were made to identify some of the products of CO2 fixation, especially amino acids. These methods, singly or in combination, have been used extensively to study CO2 fixation. The manner in which C02 is used by bacteria has been studied by the replacement technique (Lyman et al., 1947; Ajl and Werkman, 1948; Wynne and Foster, 1948). Foster et al. (1941) used radioactive C1102 to obtain direct evidence that molds fix CO2 into organic acids; recently Martin, Wilson, and Burris (1950) have used C1402 to study citric acid formation by Aspergillus nger.