Emprego de resíduo cervejeiro e NPK no cultivo de Euglena sp. : crescimento e perfil de biomassa.

Abstract

The craft brewery industry generates large volumes of wastewater during its production process and is generally discharged without any treatment. These industrial residues can be used as a culture medium for microalgae, contributing to an economically viable biomass production. As a result, wet residues from craft breweries become an interesting biotechnological alternative. The microalgae Euglena sp. is a species that has been widely studied due to the biological, ecological and economic potential of its biomolecules. In this context, this research aimed to evaluate the applicability of the use of brewery residue and NPK (12:11:18) in the cultivation of Euglena sp. considering cell growth and the nutritional profile of the biomass. Initially, different concentrations of NPK (0.5 to 6.0 g L -1) in the medium were investigated, and a brewer residue mixture (BR-Mix) was used as a supplement. Under the best growing conditions, scale-up and supplementation were carried out. In a second moment, the cultures were carried out with the medium of 0.5 g L-1 of NPK supplemented with the separated residues (malting, hopping and fermentation). Biomass was evaluated in terms of productivity and composition of lipids, proteins and carbohydrates, and for antioxidant potential. In the biomass of the cultivation with BR-Mix supplementation and lower concentration of NPK (0.5 g L-1), the lipid profile rich in polyunsaturated (61.3%) and antioxidant potential of 170.9 ± 26.3 µmol eq g-1. In scale-up and supplementation, it was observed that there was a limit of BR-Mix (10%) in which the microalgae maintained productivity. In cultures with separated residues, the fermentation residue reached a higher final productivity (1.031 g L-1), as well as the highest concentration of lipids (15.9 ± 1.3%) and proteins (39.8 ± 0.1 %). In hopping and malting residue there was a greater reserve of paramyl in the cells, evidenced by the presence of glucose as the only monosaccharide after biomass hydrolysis. Thus, it was concluded that the use of artisanal brewery waste supplementation can be used to nourish Euglena sp., especially if it is fermentation residue collected in production, allowing the use of microalgal biomass for more noble purposes.