Kinetic models for heterotrophic growth of Chlamydomonas reinhardtii in batch and fed-batch cultures

Heterotrophic growth of Chlamydomonas reinhardtii using acetate as a carbon source and nitrate, ammonium and urea as nitrogen sources in batch cultrue s was investigated. These nitrogen sources supported good growth of C. rein hardtii, the resulting cell concentrations for nitrate, ammonium chloride a nd urea were 0.48, 0.44 and 0.61 g l(-1), respectively. The specific growth rate mu(x) of the urea culture was the highest (0.071 h(-1)), followed by that of the nitrate culture (0.062 h(-1)), and the specific growth rate mu( x) of the ammonium culture was the lowest (0.058 h(-1)). Urea is therefore considered to be the best nitrogen source for the growth of the alga. Based on these results fed-batch cultures were performed to reach the maximum ce ll concentration of 1.1482 g l(-1), about 1.9-fold that obtained in batch c ulture. Finally, a group of kinetic models for describing cell growth, pH v ariation and acetate consumption were proposed and a satisfactory tit betwe en the experimental results and predicted values was demonstrated. The effe cts of dilution rate and acetate feed concentration on cell growth were ana lyzed with those with these models. (C) 1999 Elsevier Science Ltd. All righ ts reserved.