Utilization of aromatic substances by Azotobacter chroococcum.

Azotobacter chroococcum utilized catechol, protocatechuic acid and gentisic acid as sole carbon source. Rothera's test indicated the ortho cleavage of phenols. The cells displayed high levels of dioxygenase activity. Catechol was cleaved by the ortho pathway mediated by catechol 1,2-dioxygenase. Protocatechuate and gentisic acid were also cleaved by the ortho pathway and cells grown in protocatechuate and gentisic acid displayed protocatechuate, 3,4-dioxygenase and gentisate dioxygenase activity, respectively.