Efficient 2G Ethanol Production via Optimized Dilute Acid Pretreatment, High-Solids Enzymatic Hydrolysis, and High-Temperature Fermentation
Year: 2026
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide The growing demand for 2G ethanol emphasizes the need to improve its economic sustainability through different approaches, including optimized pretreatments, high-solids enzymatic hydrolysis, and high-temperature fermentation. This study evaluated the dilute acid pretreatment of deacetylated rice straw using the response surface methodology. Under optimal conditions (85 mg of H 2 SO 4 /g biomass, for 10 min at a constant temperature of 150 °C), the process was scaled up to an 80 L reactor, obtaining a cellulose-rich (58.2% w/w) pretreated solid. Then, high-solids enzymatic hydrolysis at 24% w/v solids loading was performed in a vertical ball mill (VBM) reactor in fed-batch mode, resulting in a hydrolysate of 129 g/L of fermentable sugars, which corresponded to a cellulose conversion yield (CCY) of 78.6%. Finally, the effect of nutritional supplementation of the obtained slurry and hydrolysate on the fermentability of Kluyveromyces marxianus at 43 °C was studied in conical flasks under orbital shaking. The higher Y P / S (0.46 g/g), Q P (1.74 g/L/h), and η (90%) were achieved in the hydrolysate + nutrients medium. Additionally, the effect of the VBM reactor on ethanol production was evaluated, further increasing Q P (3.04 g/L/h) with an ethanol titer of 37 g/L. Therefore, the processing sequential steps and conditions efficiently produced a glucose-rich hydrolysate, which was successfully fermented into ethanol at high temperatures and could support the process feasibility at a large scale.
Source: ACS Omega
Institution: Universidade de São Paulo
Language: English
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,935
Awards: G3271877619, G3690646728
OpenAlex ID: W7118968258