Ethanol Production from Enzymatic Hydrolysates Optimized of Agave tequilana Weber var. azul and Agave karwinskii bagasses

The use of biofuels obtained from lignocellulosic materials is a technology that offers great potential for their production in the future. Agave bagasse is one of the most common wastes produced in Mexico through the Syrup, Tequila, and Mezcal industry. In particular, Tequila and Mezcal are one of the largest alcoholic beverages in the country and thousands of tons of this waste are produced annually. Therefore, agave bagasse is a promising alternative in Mexico to obtain second-generation bioethanol (2G). In this work, the use of enzymatic hydrolysates obtained by an alkaline pretreatment and enzymatic hydrolysis optimized using Agave tequilana Weber var . azul bagasse (AT) and Agave karwinskii bagasse (AK) was evaluated for ethanol production. For this, the optimization design of alkaline pretreatment and enzymatic hydrolysis was carried out using a Box-Behnken design. Both hydrolysates were fermented using Saccharomyces cerevisiae ITV01 yeast. The results showed that the best lignin reduction in the alkaline pretreatment was 77.6 and 84.29% utilizing AT and AK, respectively. Furthermore, a glucose concentration of 100.06–98.08 and 64.03–60.0 g/L was found in the enzymatic hydrolysis (AT and AK, respectively), reaching in the fermentation step a yield of 0.47 and 0.46 g/g, volumetric productivity of 1.97 and 1.14 g/L/h and a fermentation efficiency of 93.1 and 90.4% using AT and AK, respectively. These results are interesting to use agave bagasse for ethanol production in Mexico as an alternative to give added value and take advantage of its availability.