Bioenergetic parameters of two isogenic strains of Acremonium chrysogenum markedly differing in their capacity for biosynthesis of cephalosporin C were studied. It was shown that in the high productive strain the system of oxidative phosphorylation played the dominant role in the cellular energy supply (the index of the substrate consumption eficiency amounted to 0.82). In both strains terminal oxidation of the reduction equivalents mainly occurred via the respiration chain with cytochrome oxidase as the terminal component. In the low productive strain an alternative cyanide resistant pathway was observed, in addition to the classic cytochrome chain.A procedure suitable for the isolation of stable protoplasts from the mycelium of A . chrysogenum was developed. It was proved to be useful in the isolation of functionally active mitochondria possessing theoretical phosphorylation efficiency and high phosphate acceptor respiration control. It was concluded that there are three oxidative phosphorylation sites in the respiration chain of the high productive strain of A . chrysogenum. . 1981) in Fusidium coccineum, an imperfect fungus, there were peculiar changes in the respiration system were associated with antibiotic production, i.e. there was a shift to the alternative cyanideresistant oxidation pathway. Furthermore, an increase of antibiotic production has been demonstrated by supplementing the cultivation medium with chloramphenicol as an inducer of the cyanide-resistant pathway. Moreover, salicyl hydroxamate as an inhibitor of this pathway inhibited the antibiotic synthesis. Our aim was to demonstrate analogous features in the synthesis of cephalosporin C by Acremonium chrysogenum. Therefore, respiration activities of two isogenic strains of A . chrysogenum distinguished by high and low productivity were investigated.
Correlations between bioenergetic processes and antibiotic biosynthesis
Materials and methodsStock culture: Two strains of A. chrysogenum were used: the initial strain 226 A and its mutant 12/2 309 A 20 times more active in biosynthesis of cephalosporin C than the initial strain. The strains were maintained on agar containing (g/l) : peptone 0.1, sucrose 0.4 and malt extract 0.1.Submerged cultivation: The inoculum material was grown with intensive aeration in 750 ml flasks containing 50 ml of the complex medium at 28 "C for 3 days. The inoculum (1 per cent of the volume) was added to the fermentation medium consisting of follows (g/l): sucrose 0.6, KH,PO, 0.002, L-asparagine 0.075, . 7 H 2 0 0. I , MnSO, . 4 H20 0.01, pH 6.4. The mycelium was grown in ERLENMEYER flasks (volume 750 ml) containing 50 ml of the medium at 24 "C for 2-6 days depending on the aim of the experiment.18 J.