Development of new active ingredients from microalgae biomass fermentation for human healthcare applications

Microalgae are microscopic photosynthetic organisms that produce a wide range of metabolites, such as proteins, fatty acids, carbohydrates, carotenoids and vitamins, useful for different specific industrial applications, including health care, food, cosmetics and energy production. The cyanobacteria Spirulina (Arthrospira maxima) is one of the most promising source of important metabolites, particularly proteins, lipids and phytochemicals, thus it was the focus of the research aimed at developing new active ingredients for health care applications. In order to obtain valuable products from Spirulina, a total lysate, obtained from the microalga, was subjected to three types of fermentation processes: one based on the use of indigenous bacteria (auto-fermentation), those developed spontaneously in the lysate; the second based on the use of the mix Yovisà,® (Sigma-Tau), added after a sterilization procedure of the lysate; and the third performed by employing enzymes (carbohydrase and Alcalase), thus without using any microorganism. The three extracts obtained from the fermentation processes were investigated for their antioxidant activity in protecting human cells against free radicals, then, more specifically, for inducing hydration and reduce dehydration in cultured skin cells. The results of the study underlined that the Spirulina extracts, either those derived from microbial treatments or enzymatic digestion, were significantly more efficient than the untreated samples in protecting cell membrane from oxidative stress. Moreover, those extracts obtained by enzymatic treatment showed the best hydrating and moisturizing capacity. In conclusion, the products derived from Spirulina fermentation have potential applications in both the cosmetic field, as hydrating and moisturizing agents for skin care, and nutraceutics, as food supplements that increase the natural defense response of the cells and guarantee a more efficient balance of nutrients in the body.