Thermochemical Pretreatment of Eucalyptus Wood for Bioethanol Production by Simultaneous Saccharification and Fermentation

This research aims to optimize thermochemical pretreatment of eucalyptus wood under various variables of acid concentration (0.040–0.080 M), temperature (120–160 °C) and time (30–60 min) using box-behnken design (BBD) and response surface methodology (RSM). Eucalyptus wood was treated with a thermochemical pretreatment process before being further used as the main raw material in fermentation step. The results of the study showed that the best optimal condition was performed at sulfuric acid concentration of 0.060 M with 140 °C for 40 min, leading to maximum glucose yield up to 95.50% of the actual experimental results after thermochemical pretreatment. Furthermore, the strain S. cerevisiae can be used to produce a high ethanol concentration in simultaneous saccharification and fermentation (SSF) and can consume all available glucose within 72 h with a high ethanol yield of 27.87 ± 0.15 g/L. This study provides evidence for the effectiveness of using an H2SO4 catalyst, a widely accepted method, as a viable choice for the pretreatment of wood material. The physiochemical properties of pretreated material under optimal condition were further characterized. This approach promotes the future development of second-generation bioethanol processes.