Influence of aeration on hydrogen cyanide biosynthesis byPseudomonas aeruginosa

Batch cultures ofPseudomonas aeruginosa were able to produce only low levels of cyanide during logarithmic growth with adequate aeration. The reduction of aeration caused a rapid increase in the ability of such cultures to produce hydrogen cyanide. The immediacy and the magnitude of this response depended on the oxygen level, with a concentration of 4% in the aeration gas giving optimal results. The reestablishment of normal aeration resulted in a cessation of the increase of the culture's cyanogenic capacity. This effect appeared to be a combination of inactivation of the hydrogen cyanide synthase and repression of synthesis of this enzyme.