Journal of Energy Bioscience 2025, Vol.16, No.3, 117-127 http://bioscipublisher.com/index.php/jeb 119 Figure 1 Topological analysis of pretreated sweet sorghum (SSB) and corncob (CC) feedstocks using scanning electron microscopy (SEM). The captions above the images indicate the control (untreated), type of treatment and the biomass in each SEM image. The scale bar was 20 µm and the magnification was 2.22 kx (Adopted from Mafa et al., 2020) 3.2 Suitability for bioconversion: comparison with corn stover, sugarcane bagasse, etc. Compared with corn stover, sweet sorghum bagasse has lower cellulose and hemicellulose contents, but higher lignin contents. For example, corn stover has 23.58% cellulose, 33.34% hemicellulose, and 22.51% lignin (Mafa et al., 2020). More lignin usually makes conversion more difficult. However, if sorghum biomass is treated with appropriate methods first, the saccharification rate can exceed 80%. This shows that it still has good conversion potential (Rao and Binod, 2014; Dong et al., 2019; Xu et al., 2020). Like sugarcane bagasse, cellulose can be retained after sorghum is treated with alkali or acid, while lignin and hemicellulose can be effectively removed, making it easier to enzymatically hydrolyze later (Santos et al., 2021; García-Negrón et al., 2024). After pretreatment with dilute sulfuric acid, the glucose enzymatic hydrolysis rate of some sorghum mutants can reach 82.4%, which is similar to that of well-treated corn straw and sugarcane bagasse (Xu et al., 2020). 3.3 Challenges in pretreatment and enzymatic hydrolysis Sorghum has a lot of lignin and a complex cell wall structure, which is the main difficulty encountered in bioconversion. To improve the conversion rate, pretreatment must be done first. For example, the alkaline method, acid method, hydrogen peroxide method, or "silage + alkaline method" can remove a lot of lignin and hemicellulose, making cellulose easier to be decomposed by enzymes (Dong et al., 2019; Santos et al., 2021; García-Negrón et al., 2024; Zhao et al., 2024; Bhati and Sharma, 2025). Among these methods, treatment with 2%
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