Comparison of different fermentation modes to enhance the simultaneous recycling of starch and fiber residues from processed medical plant wastes for bioethanol production

Abstract Background Treatment of ever‐increasing processed medical plant wastes (PMPWs) has become a challenging task. Numerous PMPWs are rich in starch and fiber residue (FR) and can serve as promising raw materials for bioethanol production. Simultaneously recycling the starch and FR from these PMPWs for bioethanol production is an effective approach to their utilization. This work used kudzu root waste as a model PMPW, established a novel biorefinery process to simultaneously recycle starch and FR from the PMPW for bioethanol production, and compared different fermentation modes to enhance bioethanol production. Results Sieving recovered nearly all starch in crude starch (CS) and 87.1% of cellulose in FR from PMPW. Sulfomethylation treatment increased the cellulose in the sulfomethylation‐treated FR (STFR) to 84.3 ± 1.3%, and decreased its lignin to 2.7 ± 0.2%. After simultaneous saccharification and cofermentation (SSCF) of 12.8% liquefied CS and 10% STFR for 60 h, the final ethanol concentration reached 80.9 ± 1.2 g L −1 , and the ethanol yield was 79.5 ± 1.2%. Under suitable conditions, 1 kg of PMPW yielded 0.318 kg of anhydrous ethanol, 0.322 kg of crude lignosulfonate, 0.05 kg of organic fertilizer, and approximately 50 L of biogas. Conclusions A novel biorefinery process was established to simultaneously recycle starch and FR from PMPW for bioethanol production. Among the tested modes, SSCF of liquefied CS and STFR proved to be the most suitable fermentation mode for bioethanol production from PMPWs. This work provides a new example of integrating bioethanol production with PMPW disposal. © 2026 Society of Chemical Industry (SCI).