Carbon Dioxide Sequestration by Microalgae

The term microalgae represents a large and diversified group of simple, typically autotrophic organisms. In general, microalga exists in unicellular to multi-cellular forms from different phylogenetic groups, representing many taxonomic divisions. Temperature is one of the vital factors in microalgal growth, particularly in the maintenance of cell morphology and physiology. The metabolic activities of the culture may increase or decrease as a function of temperature. The CO₂ supplementation up-regulated the gene encoding the components of pyruvate dehydrogenase complex, which is a multienzyme complex catalyzing the conversion of pyruvate into acetyl Co-A for TCA cycle. The C:N ratio plays an important role in microalgal growth. CO₂ supplementation to microalgal cultures was noted to up-regulate the genes involved in nitrogen acquisition and assimilation. Microalgal CO₂ sequestration provides an opportunity to reduce environmental impacts of CO₂, use of fossil fuels for energy, and to produce various food and feed grade high value metabolites at a cheaper cost.