Ethanol effect on batch and fed-batch Arthrospira platensis growth

The ability of Arthrospira platensis to use ethanol as a carbon and energy source was investigated by batch process and fed-batch process. A. platensis was cultivated under the effect of a single addition (batch process) and a daily pulse feeding (fed-batch process) of pure ethanol, at different concentrations, to evaluate cell concentration (X) and specific growth rate (mu). A marked increase was observed in the cell concentration of A. platensis in runs with ethanol addition when compared to control cultures without ethanol addition. The fed-batch process using an ethanol concentration of 38 mg L-1 days(-1) reached the maximum cell concentration of 2,393 +/- A 241 mg L-1, about 1.5-fold that obtained in the control culture. In all experiments, the maximum specific growth rate was observed in the early exponential phase of cell growth. In the fed-batch process, mu decreased more slowly than in the batch process and control culture, resulting in the highest final cell concentration. Ethanol can be used as a feasible carbon and energy source for A. platensis growth via a fed-batch process.