Title : Cultivating chlorella vulgaris in tubular photobioreactors: A potential lipid source for biodiesel generation
Abstract:
Chlorella vulgaris was grown in two distinct types of photobioreactors, specifically 2.0 L helicoidal and horizontal designs, under light intensity of 5 klux, utilizing bicarbonate from the medium and ambient air as primary sources of CO2. The effect of bicarbonate concentration on biomass growth, as well as lipid content and profile, was initially assessed in shake flasks, where the stationary phase was reached in approximately half the time compared to the control. The optimal concentration of NaHCO3 (0.2 g L−1) was subsequently applied in both photobioreactor types. The fed-batch operation in the helicoidal photobioreactor yielded the highest biomass productivity, achieving 84.8 mg L−1 d−1, which is about 2.5 times greater than that of the batch process. Conversely, the horizontal photobioreactor demonstrated superior lipid productivity at 10.3 mg L−1 d−1, attributed to a higher lipid content in the biomass (22.8%). These initial findings indicate that the design of the photobioreactor significantly influences both the growth and composition of this microalga. The lipid quality of C. vulgaris biomass cultivated in both systems is anticipated to comply with biodiesel standards, particularly in the helicoidal setup, contingent upon further optimization of production conditions for biodiesel applications.
