Simultaneous saccharification and fermentation of Spirulina sp. and corn starch for the production of bioethanol and obtaining biopeptides with high antioxidant activity

Abstract

The aim was to produce bioethanol by the simultaneous saccharification and fermentation (SSF) of Spirulina sp. LEB 18 biomass and corn starch, increasing the process scale and obtaining biopeptides from bioethanol residue. Different temperatures of SSF and biomass/starch concentrations were tested, and the best conditions were chosen to scale-up the bioethanol production. The biopeptides were obtained enzymatically with a protease. The antioxidant capacity, molecular structure, thermal stability and mass loss of the biopeptides were evaluated. A total of 73 g L^-1 bioethanol was obtained during scale-up, and the residue presented a high protein content with a degree of hydrolysis of 86%. The biopeptides showed 32% ABTS radical inhibition with high thermal stability. This study showed the possibility of the biorefinery concept being able to produce bioethanol by Spirulina, and the biopeptides from the bioethanol residue presented high antioxidant capacity and can be used in many areas of the food industry.

Keywords: Antioxidant capacity; Bioethanol; Biopeptides; Biorefinery; Microalgae.