Pretreatment of olive tree biomass with FeCl3 prior enzymatic hydrolysis

Olive tree biomass (OTB) is an agricultural residue which can be used as raw material for bioethanol production. OTB was pretreated with 0.05–0.275 M FeCl3 solutions at 120–180 °C for 0–30 min. Enzymatic hydrolysis yields were used for assessing pretreatment performance. Optimum FeCl3 pretreatment conditions were found to be 152.6 °C, 0.26 M FeCl3 for 30 min. Under such conditions, 100% of hemicellulose was removed, and enzymatic hydrolysis of pretreated solids resulted in a yield of 36.6 g glucose/100 g of glucose in the raw material. Hemicellulosic sugar recovery in the prehydrolysate was 63.2%. Results compare well with those obtained by other pretreatment strategies on the same raw material, confirming FeCl3 solutions as a new, feasible approach for bioethanol production.