Effects of Medium Composition on the Growth of Chlorella vulgaris During Photobioreactor Batch Cultivations

摘要

A promising alternative to petroleum-derived fuels lies in microalgae-produced biodiesel. Compared to major terrestrial crops, microalgae have higher rates of oil and biomass production and appear to be the only source of renewable biodiesel that can meet global demand for transport fuels. Chlorella vulgaris may be suitable for biodiesel production due to its faster growth and easier cultivation compared to other strains. Lipid production is achieved in two steps: a biomass production phase, and a lipid production phase, in which the lipid content of algal cells is increased by submitting them to environmental stress such as nitrogen starvation. As a preliminary step towards the optimization of the biomass production step, the effect of different nutrient concentrations in TAP medium on the photobioreactor cultivation of C. vulgaris was studied. The results showed good growth of Chlorella vulgaris in 2X TAP, reaching a biomass concentration of 6.0 g/liter. Growth inhibition was observed at concentrations of the nitrogen source, NH_(4)Cl, between 500 and 1000 mg/liter in the medium. Varying the concentration of the phosphorus source, K_(2)HPO_(4) in the medium had no effect on cell growth within the range studied, provided phosphorus sufficiency is ensured. Other medium components are non-limiting at the levels studied.