Potencial biotecnológico de Synechococcus nidulans cultivada em meio alternativo utilizando extrato de bagaço de caju

Abstract

The cultivation of microalgae has attracted a lot of attention in recent years, since these microorganisms are sources of bioactive compounds that offer a wide area of application, including in the area of cosmetics. Particularly, Brazil has the fourth largest cosmetics market in the world, as well as favorable climatic conditions for the cultivation of microalgae. However, given the numerous species of microalgae that are little explored and the high cost of biomass production, it is necessary to invest in research that involves the study of little-studied species and low-cost biomass production strategies. In this sense, the objective of this research was to evaluate the potential of the microalgae Synechococcus nidulans, a species little studied, using mixotrophic cultures with the addition of Cashew Bagasse Extract (EBC) as an organic carbon source in order to increase biomass production and evaluate the potential production of bioactive compounds of interest to the cosmetics industry. S. nidulans cultivation experiments were carried out under autotrophic and mixotrophic conditions with different concentrations of EBC (0.5%, 1.5% and 2.5% (v/v)) and the biomass composition was determined in terms of carbohydrates, proteins, lipids, ash and carotenoids. Cultivations were carried out in triplicate, under controlled conditions (temperature of 24 ± 1ºC, light intensity of approximately 310 µmol/m2/s photons, provided by 5 fluorescent lamps of 40 W, constant aeration, photoperiod of 12 h light/dark). Crops subjected to stress with EBC indicated better biomass yields. A 25.9% drop in ash levels was observed in mixotrophic cultivation with the addition of 2.5% (v/v) of EBC, unlike carbohydrate levels, which increased by up to 28.5% with the addition of 2.5% (v/v) of EBC in relation to the control culture. The results showed that the use of EBC in the production of bioactives by microalgae reduced the yields of total lipids and total carotenoids in relation to the control culture (13.22% ±0.25% and 10.02mg/g ±4.33 mg/ g). However, the increase in biomass production in mixotrophic crops justifies the increased production of bioactives at a lower cost compared to control. Regarding total protein production, the cultivation with addition of 2.5% EBC stood out, presenting 54.07% ±3.59%. Thus, the results demonstrate that the microalgae under study contains biocompounds of interest to the cosmetics industry and that these can be explored in mixotrophic cultivation with agro-industrial residues as a source of organic carbon.