Bioconversion of lignocellulose in ensiled Caragana korshinskii Kom. into bioethanol by ferulic acid esterase-producing Limosilactobacillus reuteri A4-2 and Acremonium cellulase

Woody and agricultural residues, such as Caragana korshinskii Kom. (Korshinsk pea shrub), have gained significant attention as a sustainable feedstock for biofuel production. This study developed a novel ensiling approach by combining ferulic acid esterase-producing Limosilactobacillus reuteri A4–2 (LR) with Acremonium cellulase (AC) as additives to enhance bioethanol production from C. korshinskii. Four treatments were: biomass ensiled without additive (control), or with LR, AC, and a combination of LR with AC for 3, 7, 14, 30, and 60 d. The addition of LR, AC, or both improved fermentation quality by inhibiting undesirable bacteria and modifying the microbial communities, leading to increased lactic acid, ferulic acid and crude protein contents, with a lower ammonia nitrogen content in C. korshinskii silages. These treatments also enhanced the degradability of structural carbohydrates releasing more fermentable sugars after ensiling, with the LR+AC showing the best results. Spectroscopic analyses provided visual evidence of chemical bond disruption, morphological changes, and decrystallization in the ensiled C. korshinskii. Separate hydrolysis and fermentation (SHF) experiments conducted with the silages which revealed that pretreatment with LR+AC improved cellulose conversion and ethanol yield by 9.9 % and 53.4 % compared to the control, achieving a maximum ethanol yield of 29.4 % during SHF process. The Sankey diagram showed that L. reuteri abundance was positively correlated with improved silage quality, which in turn was correlated to higher ethanol yield. Overall, ensiling C. korshinskii with L. reuteri A4–2 and Acremonium cellulase provides a promising strategy for efficient biofuel production from lignocellulose biomass.