Microalgae as a source of bioavailable heme.

Heme is an iron-coordinated tetrapyrrole molecule that plays an indispensable role in various biological processes such as respiration, oxygen metabolism, oxygen transfer, photosynthetic electron transportation and oxidative stress responses. Heme is also the primary source of functional, bioavailable iron in the human body. Iron deficiency results in a range of acute and chronic human health consequences. Iron deficiency anemia affects approximately 25 % of the global human population. New sources of bioavailable heme are required to help combat this ubiquitous mineral deficiency. Microalgae do biosynthesize heme but our knowledge of the regulation of those pathways, what the actual yields of heme may be, and how heme yields may be improved is restricted to a few model species. In this review we explore the potential of microalgae as an alternative source of bioavailable heme, suggest some strategies that may be pursued, and highlight some of the challenges that still need to be overcome. Developing heme enriched microalgae could transform our access to bioavailable iron through direct use as a dietary supplement and/or incorporation into functional foods. • Critical analysis of heme biosynthetic pathway in microalgae • Analysis of abiotic triggers of heme biosynthesis in microalgae • Identification of potential molecular targets to increase heme synthesis • Critical appraisal of microalgae as a source of bioavailable heme • Reflection on upscaling production to tackle global nutritional iron deficiency [ABSTRACT FROM AUTHOR]