Alterations of respiratory systems in Aspergillus niger under the conditions of citric acid fermentation.

Under the conditions of citric acid fermentation, Aspergillus niger WU-2223Lpossessed at least two respiratory systems.Onesystem wassensitive to cyanide (CN) and the other was sensitive to salicylhydroxamic acid (SHAM).The respiration of mycelia was partially, inhibited by CNor SHAM, and was completely inhibited in the presence of both CNand SHAM.With culture time, the CN-sensitivity of respiration decreased and the SHAM-sensitivity increased.The respiratory rate itself decreased suddenly at 4 days and thereafter remained at a low level.The SHAM-sensitive respiration was localized in the mitochondria.The alterations of respiration in the mitochondria were similar to those observed in mycelial cells.