Integrated simultaneous fermentation–pervaporation for intensified bioethanol production and recovery in a corn stover cascade biorefinery

Corn stover was valorized through an integrated cascade biorefinery combining subcritical water pretreatment, enzymatic hydrolysis, alcoholic fermentation, and pervaporation for intensified bioethanol production and recovery. Subcritical water treatment effectively solubilized the hemicelluloses while increasing cellulose accessibility in the solid residue. This enabled glucose yields of approximately 80% after 24 h of enzymatic hydrolysis. The resulting hydrolysate was then used in two strategies for the production and recovery of bioethanol. In the first one, the glucose-rich liquid was efficiently fermented by Saccharomyces cerevisiae, achieving complete glucose consumption within 15 h and an ethanol yield of 91%. Subsequently, ethanol was recovered through pervaporation, where silicone membranes were identified as the most suitable option due to their superior permeation performance. A novel integrated simultaneous fermentation-pervaporation (SFP) approach was developed as the second strategy to intensify bioethanol production and recovery by coupling both processes in a single operation. Operating the hybrid process at 38 °C substantially enhanced ethanol removal, allowing 98% of the produced ethanol to be recovered within only 15.3 h, compared with 60% recovery achieved by the sequential strategy. SFP at 38 °C achieved the highest overall yield, reaching 97% and demonstrated that integrating fermentation and pervaporation at this temperature effectively improved ethanol recovery and process productivity, providing a promising approach for sustainable lignocellulosic biorefineries.