Intracellular pH and metabolic activity of long-chain dicarylic acid-producing yeast Candida tropicalis.

The intracellular pH (pH(i) of alpha-omega-dicarylic acid producing Candida tropicalis was determined by a fluorescence technique using the pH-sensitive fluorescent probe 5(6)-carboxyfluorescein diacetate. Fermentations with n-tridecane substrate to produce alpha,omega-tridecanedioic acid were carried out in a 5-l bioreactor in which growth and production were separated. During the growth phase, the measured pH(i) values were varied from 5.