Total Lipid Production of Microalgae Chlorella sp. and Chlorella Vulgaris under Mixotrophic Culture Conditions

Abstract

The freshwater microalgae Chlorella sp. and Chlorella Vulgaris were cultured in a laboratory-scale photobioreactor and their growth kinetics and total lipid production were evaluated. These species were grown in a modified Conway medium, with an 8:16 photoperiod and mechanical air ventilation. The evaluation time was twenty days, the cell density was determined daily using the Neubauer chamber and by optical density using spectrophotometry at 685 nm. The growth rate and the percentage of total lipids produced were determined, the biomasses obtained were analyzed by Fourier transform infrared (FTIR) spectroscopy. The comparison of the growth kinetics showed a significant difference between the growth of the species, reaching maximum growth values of 7,022,000 cells · mL-1 for Chlorella sp. and 8,750,000 cells · mL-1 for Chlorella vulgaris. The Chlorella species showed a growth rate of 0.298 days-1, which was slightly higher than Chlorella Vulgaris, which was 0.279 days-1. The results also show that the highest total lipid production species was Chlorella sp. (27.3%), compared to Chlorella vulgaris (21.5%)