Dialyzed paper pulp waste liquor added at 20% (v/v) basal medium improved the production of indole alkaloid, catharanthine, from Catharanthine roseus, yielding 51 mu g/cell as against 42 mu g/cell in non-supplemented medium. 30-40% (v/v) of catharanthine was secreted out of the cells, showing that the change of the ratio of inner to outer concentrations was from 12.3 to 2.2 at dilution rate of 0.1 h(-1) during chemostat cultivation. An optimal dilution rate was 0.34 h(-1) in 20% (v/v) supplemented medium, compared to 0.22 h(-1) in non-supplemented medium.