ABSTRACT
Microalgae cultivation, when compared to the growth of higher plants, presents many advantages such as faster growth, higher biomass productivity, and smaller land area requirement for cultivation. For this reason, microalgae are an alternative platform for carotenoid production when compared to the traditional sources. Currently, commercial microalgae production is not well developed but, fortunately, there are several studies aiming to make the large-scale production feasible by, for example, employing different cultivation systems. This review focuses on the main carotenoids from microalgae, comparing them to the traditional sources, as well as a critical analysis about different microalgae cultivation regimes that are currently available and applicable for carotenoid accumulation. Throughout this review paper, we present relevant information about the main commercial microalgae carotenoid producers; the comparison between carotenoid content from food, vegetables, fruits, and microalgae; and the great importance and impact of these molecule applications, such as in food (nutraceuticals and functional foods), cosmetics and pharmaceutical industries, feed (colorants and additives), and healthcare area. Lastly, the different operating systems applied to these photosynthetic cultivations are critically discussed, and conclusions and perspectives are made concerning the best operating system for acquiring high cell densities and, consequently, high carotenoid accumulation.
Subject(s)
Carotenoids/metabolism , Drug Industry , Food Industry , Microalgae/metabolism , Biomass , EcosystemABSTRACT
Since cultivations of Arthrospira platensis have a high water demand, it is necessary to develop treatment methods for reusing the exhausted medium that may prevent environmental problems and obtaining useful biomass. The exhausted Schlösser medium obtained from A. platensis batch cultivation in bench-scale mini-tanks was treated by varying concentrations of different coagulants, ferric chloride (6, 10, and 14 mg L-1) or ferric sulfate (15, 25, and 35 mg L-1) and powdered activated carbon (PAC, 30 and 50 mg L-1). Such treated effluent was restored with NaNO3 and reused in new cultivations of A. platensis performed in Erlenmeyer flasks. Reusing media through the cultivation of A. platensis showed satisfactory results, particularly in the medium treated with ferric chloride and PAC. The maximum cell concentration obtained in the flasks was 1093 mg L-1, which corresponded to the medium treated with ferric chloride (6 mg L-1) and PAC (30 mg L-1). This cellular growth was higher than in the medium treated with ferric sulfate and PAC, in which values of maximum cell concentration did not exceed 796 mg L-1. The cultures in the media after treatment did not modify the biomass composition. Thus, combined coagulation/adsorption processes, commonly used in water treatment processes, can be efficient and viable for treating exhausted medium of A. platensis, allowing the production of such biomass with the reduction of production cost and saving water.
