Pioneering industrial culture of mixotrophic microalgae

Microalgae has received much attention in the recent years for it capacity to utilize solar energy and convert carbon dioxide into storage energy (i.e., photoautotrophy). Large scale microalgae production using solar energy as a free energy source and carbon dioxide is generally carried out in low cost culturing system comprising a shallow (30 cm) open ponds.  Although microalgae can be cultivated in inexpensive systems and utilize a free source of energy, process economics are determined by the low cell densities that results from meager light penetration into the culture broth of such systems.  The process economics may be improved thanks to the metabolic versatility observed in mixotrophic microalgae, which can simultaneously utilize solar energy, and uptake/oxidize an organic carbon source as both an energy and carbon source.  Small scale systems have demonstrated that mixotrophy could increase the cell densities above the photoautotrophic compensation point and improve the economics in a relatively low cost culturing system, but this approach has rarely been scale up due to risks associated with microbial control. Heliae, an Arizona based Microalgae Company, has pioneered an industrial mixotrophic approach which addresses such economic and technical challenges.