Explorando o potencial biotecnológico de Euglena Gracilis como estratégia para inovações na produção de bioprodutos e soluções ambientais sustentáveis.

Abstract

Microalgae, as a group of highly diverse organisms, have been widely recognized for their numerous applications, ranging from wastewater treatment to biotechnology and the development of bioproducts. However, the vast biodiversity of these species remains underexplored, limiting the full potential of this group. Euglena gracilis (Euglenophyceae) is a species with an impressive evolutionary history, reflected in its resistance and adaptability to extreme environmental conditions, as well as its sophisticated and versatile metabolism, which allows for the synthesis of a wide range of high-value bioactive biomolecules, such as polyunsaturated fatty acids, amino acids, vitamins (C and E), and exclusive biomolecules, such as β-1,3-D-glucan (paramylon) and euglenatides. In this context, the main objective of this research was to investigate the biotechnological potential of E. gracilis through its biochemical characterization and evaluation of its biological activities, with an emphasis on antioxidant and biostimulant potential, while also exploring its use in sustainable environmental solutions, such as wastewater treatment. The methodology involved culturing the microalga under photo- and mixotrophic conditions, using different media and cultivation conditions: conventional BG11, modified BG11 enriched with mineral fertilizer NPK (BG11NPK), Synthetic Urban Effluent (SUE), as well as natural wastewater from pig farming diluted to 25% (P25) and pre-treated with photo-Fenton (PF). Growth and productivity parameters were assessed, and the biochemical composition was analyzed through conventional and alternative techniques, such as chromatography and FTIR spectroscopy. The antioxidant and biostimulant potential were evaluated through germination index and Oxygen Radical Absorbance Capacity (ORAC) assays. Additionally, standard methods for effluent analysis were used, focusing on the efficiency of E. gracilis in nutrient removal from piggery wastewater. The results demonstrated consistent growth and productivity in alternative media and wastewater, emphasizing its viability in piggery wastewater, promoting nutrient reduction and producing biomass rich in bioactive compounds, especially with biostimulant activity. FTIR spectroscopy, combined with multivariate analyses, provided insights into how cultivation conditions influence the metabolism and antioxidant capacity of the microalga, allowing for the optimization of the production of target compounds. This approach proved effective for a preliminary evaluation of the cellular composition of E. gracilis in a sustainable manner, minimizing the use of chemical reagents and reducing analysis time. The results demonstrate the potential of the microalga to produce high-value bioproducts, simultaneously with its use as a tool in wastewater treatment. This study reflects not only environmental benefits, such as removing nutrients from wastewater but also biotechnological gains, with the production of bioactive compounds of industrial interest. This work establishes the foundation for applying E. gracilis in industrial processes, with an impact on environmental sustainability.