Hydrogen Production by Anaerobic Digestion from Agave lechuguilla Hydrolysates

Hydrogen production from enzymatic hydrolysates of Agave lechuguilla pretreated by autohydrolysis was assessed in this work. The pretreatment was carried out in a high-pressure reactor using a solid/liquid ratio of 1:6 (w/v) at 190 °C for 30 min at 200 rpm. The pretreated solids were enzymatically hydrolyzed and then were digested with a treated mixed consortium under specified conditions with a Taguchi (L9(34)) experimental array. The results showed that the xylan was 65.2% solubilized during pretreatment, and the glucan preserved was 77.5% hydrolyzed, obtaining a hydrolysate with 55 g/L of glucose. The production of hydrogen after anaerobic digestion of hydrolysates was significantly influenced mainly by the temperature (80.6%) and glucose concentration (15.1%). The best conditions were 40 oC, glucose 20 g/L, inoculum 5% (v/v), and initial pH 7. Under optimal conditions, the hydrogen yield achieved was 3.48 mol H2/mol glucose consumed at 120 h.