**Abstract**

The blue cabuya (*Agave americana L.*) grows wild on large tracts of land in various regions of Peru. The research is aimed at taking advantage of this renewable plant biomass as a potential substrate in one of its possible applications such as cabuya azul liquor, for which, firstly, the yields of the anaerobic fermentation process of this biomass at temperatures of 26, 28 and 30 C and a pH of 3.5 and 4.0, in a batch bioreactor of 120 liters and nutrient concentrations of diammonium phosphate (DAP) of 1 and 2 g/L and a substrate with reducing sugars (AR) of 60 g/L from the district of La Merced, province of Churcampa, Huancavelica Region. The experimental tests were carried out in the laboratories of the Faculties of Biological Sciences and Chemistry and Chemical Engineering of the Universidad Nacional Mayor de San Marcos. Using *Saccharomyces cerevisiae yeast strains* (D 47, LALVIN-Canada) at 28 C, pH 3.5 and DAP nutrient concentration of 2 g/L during 26 h of fermentation, was obtained total biomass yields Y(x/s) =. 0.1606 and ethanol Y(p/s) = 0.4739. It is concluded that the production of ethanol for use in its industrialization as blue cabuya liquor is viable and for the transfer of technology environmental aspects and economic studies must be integrated.

**Keywords:** blue cabuya, substrate, *Saccharomyces cerevisiae*, diammonium phosphate, ethanol production
