Co‐culture‐based bioconversion of sugarcane bagasse into bioethanol with <i>Saccharomyces cerevisiae</i> and <i>Pseudomonas aeruginosa</i> by separate hydrolysis and fermentation

Abstract This study examined the use of Saccharomyces cerevisiae and Pseudomonas aeruginosa as a mixed microbial culture to enhance bioethanol production from sugarcane bagasse (SCB). Traditional single‐culture fermentation is limited by substrate utilization and environmental fluctuations, whereas mixed‐culture fermentation exploits the complementary metabolic activities of both microorganisms. Sugarcane bagasse was pretreated with 2% v/v sulfuric acid (H 2 SO 4 ), followed by enzymatic hydrolysis and separate hydrolysis and fermentation (SHF). The optimal cellulase: β ‐glucosidase ratio (1:4) produced the highest glucose concentration (8.28 ± 0.06 g L −1 ). Response surface methodology (RSM) predicted a bioethanol yield of 3.48 g L −1 (0.17 g/g SCB‐to‐ethanol) with 82.4% conversion efficiency. Experimental validation using the S. cerevisiae – P. aeruginosa system yielded 3.43 g L −1 of bioethanol (0.172 g/g SCB‐to‐ethanol) and an 81.23% conversion efficiency under the optimized conditions (7.36% (v/v) total inoculum, 72 h, 30 °C, pH 4.8). This study demonstrates the advantages of mixed‐culture fermentation, showing improved efficiency and potential cost reductions for large‐scale bioethanol production.