Characteristics and potential of micro algal cultivation strategies: a review

The review highlights the correlation between removal of various eco-toxins by micro algae and the production of high-value products thereof. It appraises established and novel strategies for micro algal cultivation, downstream processing methods for product recovery, and recent progress in algal generation of the green energy carriers biogas and biohydrogen micro algae. The suitability of selected micro algal species for various final products, and the potential of different strains for abating environmental problems are discussed. the fact that low cell densities and moderate growth rates are known as the major obstacles towards a broad market penetration of micro algal products, the article shows how high cell densities and reasonable volumetric productivities can be obtained. Here, the article deals with the improvements of process design and nutrient supply regimes that are needed to achieve these goals. onstrated by an integrated case study, mixotrophic cultivation results in increased biomass concentration in a first cultivation step for some micro algal strains like Nannochloropsis oculata. In a second step, the fresh active algal biomass accumulates desired products via CO2 fixation, e.g. from industrial effluent gases, as the sole carbon source. This can be realized by a novel, two-stage, continuously operated closed photo-bioreactor system. After cell harvest and optimized product recovery, the value-added conversion of residual algal biomass for generation of green energy carriers, e.g. in biogas plants, constitutes another focal point of the ongoing research.