Production and Broad Characterization of a Spirulina platensis Dry Powder Grown in Bubbled Columns

Aims: The aim of this work was to show the feasibility of growing Spirulina platensis in bubbled photo-bioreactors in a defined medium and after recovery and drying processes, to obtain a dry powder with food and nutraceutic characteristics such as those obtained by the proximal analysis, lipids and pigments profile, metals content, quelant and radical scavenger, antioxidant and antibiotic properties.

Place and Duration of Study: The work was carried out at Unidad Profesional Interdisciplinaria de Biotecnologia-IPN (Mexico City) facilities during 2017.

Methodology: In this paper, the mass production of microalgae in four 200 L bubbled column addresses growing in alkaline and saline, under ambient conditions and the complete characterization of the product in terms of its proximate analysis, metal content and the ability to inhibit growth of some microorganisms. A phytochemicals profile was carried out (qualitative results), the antibiotic activities against Gram negative and positive strains and an analysis of the present lipids and pigments were carried out. Finally, antioxidant and radical scavenging properties of the product were measured.

Results: Photo-bioreactor 1 produced the highest concentration of biomass, although the largest mass of wet weight (757.6 g) and dry (160.8 g), were observed for the photo-photo-bioreactor 4. The photo-bioreactor 4 reached a mass productivity of 2.39 mg L-1h-1. On average, 153.35 g dry mass per photo-photo-bioreactor were produced, with a mass productivity of 2.28 mg L-1h-1. The obtained product compared well to a commercial one, with similar content of carbohydrates, protein, lipid, fiber, ash and total moisture (%). A phytochemicals profile was carried out (qualitative results). Regarding the Mexican standards, the product is below the recommended values only for ashes and crude fiber. Several alkaline earth and heavy metal values were found in the product. When calculating the intake of an adult weight of 70 kg who ingested 4 g day-1 of Spirulina, the values are not higher than the recommended intake for an adult by various associations (FAO/WHO, among them). It also found that the product had antibiotic activity against some Gram-positive and Gram-negative bacteria strains. It was also identified that the product had antioxidant and chelating activities and an analysis of the present lipids and pigments were carried out.

Conclusion: It can be said that the culture process in the bubbled photo-bioreactors generates a dry product with excellent food and nutraceutic properties which can be employed to solve malnutrition problems that small communities are experiencing in Mexico.