Photobiology of microalgae mass cultures: understanding the tools for the next green revolution

Abstract

Several obstacles and limitations currently prevent the industrial exploitation of microalgae for feed, food and biofuel production. Photobioreactors (closed systems for algae cultivation) suffer from high-energy expenditures for mixing and cooling, while cultures in large-scale open ponds, which have a more favorable net energy ratio, are unstable ecosystems in which maintaining selected strains for long periods is difficult. Techniques for supplying nutrients and CO₂, for mixing and for harvesting and processing the biomass in an energy-efficient manner are still under study and development. Despite these impediments and although microalgae are not superior to higher plants in terms of photosynthetic efficiency and productivity, microalgal cultures remain one of the most attractive sources of feed, food and next-generation biofuels since microalgae can be grown in saline or seawater on nonarable lands, can use fertilizers with an almost 100% efficiency, are able to attain much higher oil and protein yields than traditional crops and, being endowed with high growth rates, are easier to be improved via genetic and metabolic engineering.

Acknowledgements

The author is grateful to Juergen Polle, Associate Professor in the Department of Biology of the Brooklyn College of the University of New York, USA and to Graziella Chini Zittelli, researcher at the Consiglio Nazionale delle Ricerche of Italy, for critically reading the manuscript and helpful discussion.

Financial & competing interests disclosure

The author is a consultant of companies in the field, a member of the scientific advisory board of Aurora Biofuels and member of the Board of Fotosintetica & Microbiologica. The author has no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.