Background: Since the industrial revolution, the consumption of processed food increased
dramatically. During processing, food material loses many of its natural properties.
Objective: The simple restoration of the original properties of the processed food as well as fortification
require food supplementation with compounds prepared chemically or of natural origin. The observations
that natural food additives are safer and better accepted by consumers than synthetic ones
have strongly increased the demand for natural compounds. Because some of them have only a low
abundance or are even rare, their market price can be very high. This is the case for most carotenoids of
natural origin to which this review is dedicated. The increasing demand for food additives of natural
origin contributes to an accelerated depletion of traditional natural resources already threatened by intensive
agriculture and pollution. To overcome these difficulties and satisfy the demand, alternative
sources for natural carotenoids have to be found. In this context, photosynthetic microalgae present a
very high potential because they contain carotenoids and are able to produce particular carotenoids under
stress. Their potential also resides in the fact that only ten thousands of microalgal strains have
been described while hundred thousands of species are predicted to exist. Carotenoids have been
known for ages for their antioxidant and coloring properties, and a large body of evidence has been accumulated
about their health potential.
Conclusion: This review summarizes both the medicinal and food industry applications of microalgae
with emphasis on the former. In addition, traditional and alternative microalgal sources used for industrial
carotenoid extraction, the chemical and physical properties, the biosynthesis and the localization
of carotenoids in algae are also briefly discussed.