2026-04-23T05:53:09Zhttps://riubu.ubu.es/oai/request

oai:riubu.ubu.es:10259/104462025-05-09T00:05:15Zcom_10259_4244com_10259_5086com_10259_2604col_10259_4245

Candela Gil, Helena Illera Gigante, Alba Ester Barea Gómez, Pedro Ruiz Pérez, María Olga Beltrán Calvo, Sagrario Sanz Díez, Mª Teresa Alkaline catalysis Subcritical water Lactic acid Corn stover Molar ratio OH-/sugar monomers The optimization of hydrothermal lactic acid (LA) production from corn stover using Ca(OH)2 as catalyst was investigated. Initial studies with a 9 g L−1 glucose solution, and different Ca(OH)2 concentrations, in the range of 0.025–0.1 M, identified 0.075 M as the optimal concentration. Ca(OH)2 acted both as catalyst and reactant, neutralizing LA, and other organic acids produced, primarily acetic and formic acids. Excess Ca(OH)2 was required to maintain the alkaline environment necessary for LA production, achieving 3.5 g LA L−1 with a 40% yield. Lactic acid production from corn stover was studied at temperatures ranging from 90 to 260 °C with 0.075 M Ca(OH)2 and a biomass loading of 5 wt%. Higher temperatures increased LA production reaching 5.9 g LA L−1 with 15.1% of yield at 260 °C. The lower value of the yield compared with that obtained from glucose was attributed to the lower OH−/sugar monomer molar ratio, which was 3 for glucose, but only 0.65 for corn stover. To counteract organic acid formation, Ca(OH)2 concentrations up to 1.5 M were tested. The OH−/sugar monomer molar ratio emerged as a key design parameter, with an optimum value of 2.61, resulting in 12.4 g LA L−1 and 32% yield. This ratio compensates Ca(OH)2 consumption in neutralization reactions and minimizes excess base, which primarily remained in the solid residue owing to the low solubility of Ca(OH)2 in water. This approach also achieves minimal mass intensity, with 5.8 kg of reactants kg−1 of LA, with unnecessary reactant consumption. 2025-05-08 2025-05-08 2025-04 info:eu-repo/semantics/article 1932-104X http://hdl.handle.net/10259/10446 10.1002/bbb.2785 1932-1031 eng Biofuels, Bioproducts and Biorefining. 2025 https://doi.org/10.1002/bbb.2785 info:eu-repo/semantics/openAccess Wiley