Microalgal biomass as a sustainable alternative raw material

Microalgae are potential purveyors of various natural substances of commercial value. Their use is based upon their relatively efficient photosynthetic machinery and is associated with the availability of appropriate sites, surplus CO2, nutrients, solar irradiation and heat. For production to meet sustainability criteria while maintaining a competitive edge, a series of cumulative conditions must be observed, along with the prerequisites of quality and naturalness. These include complete utilisation of biomass produced, media recycling, attractive yearlong production rates, low risk of contamination, low costs for biomass harvesting and for the delivery of the active principles(s) obtained as efficacious and stable ingredients. These are ever present criteria in the work developed by the authors' group, and illustrative examples will be presented briefly. A lengthier presentation is given on the onset and peculiarities of carotenogenesis in a Chlorella sp., as well as on the evaluation of carotenoid pigments thus obtained as ingredients in the food chain, namely by inclusion in a finishing feed in order to ensure colouring of rainbow trout (Oncorhyncus mykiss) muscle.