Journal of Energy Bioscience 2024, Vol.15, No.1, 20-27 http://bioscipublisher.com/index.php/jeb 23 In recent years, the bagasse papermaking process has made significant technological progress. New pretreatment technologies, such as alkali pretreatment, steam explosion and organic solvent methods, have improved fiber separation efficiency, reduced chemical consumption, and improved pulp quality. The use of environmentally friendly bleaching agents such as oxygen and hydrogen peroxide instead of traditional chlorine bleaching improves the whiteness of the pulp and reduces pollution emissions during the bleaching process. In addition to traditional paper products, bagasse can also be used to produce new materials such as nanocellulose, composite materials, and bioplastics, expanding its application in the paper industry (Vangchhia et al., 2024). Although the bagasse papermaking industry has significant value-added potential, it still faces some challenges, including unstable fiber quality, imperfect process technology, and uncertain economic benefits. However, as the demand for renewable biomass resources continues to increase, the value-added application of bagasse in the paper industry will become an important direction for the recycling of sugarcane by-products. 2.2 Sugarcane bioenergy and biofuel production Sugarcane bagasse (SCB) is an important raw material for the production of bioenergy and biofuels. As one of the main by-products of the sugar industry, bagasse is rich in cellulose and hemicellulose, which makes it an ideal substrate for the production of biofuels, especially bioethanol. Generally, bagasse accounts for 25% to 30% of the total mass of sugarcane, and its components mainly include cellulose (40% to 50%), hemicellulose (25% to 35%) and lignin (20%). Key steps in bagasse biofuel production include pretreatment, enzymatic hydrolysis, fermentation and distillation. Pretreatment is a key step in improving bagasse biofuel production. Common pretreatment methods include alkali method, acid method, steam explosion and organic solvent method. The purpose of pretreatment is to remove lignin from sugarcane bagasse and improve the enzymatic hydrolysis efficiency of cellulose and hemicellulose (Ajala et al., 2021). At present, the combined technology of alkali method and acid method shows superiority in sugarcane bagasse pretreatment and can significantly increase sugar yield (Kakasaheb et al., 2021). In the production of bioethanol, pretreated bagasse undergoes enzymatic hydrolysis to convert cellulose and hemicellulose into fermentable sugars, which are then converted into ethanol through yeast or bacterial fermentation. In recent years, new fermentation technologies (such as co-culture method, combined fermentation) and improved yeast strains (such as Saccharomyces cerevisiae, Candida tropicalis, etc.) have further increased ethanol production. In addition to bioethanol production, bagasse can also be used to produce other forms of bioenergy and fuels, such as biogas, lignocellulosic biodiesel, and biohydrogen. For example, a combination of alkali pretreatment and enzymatic hydrolysis can significantly increase biomethane production from sugarcane bagasse. In addition, bagasse can also be used as a direct fuel for biomass power generation. Especially in countries with developed sugarcane industries such as Brazil, bagasse has become an important raw material for power generation in sugar factories (Ajala et al., 2021). 2.3 Sugarcane chemicals and materials Sugarcane bagasse is the fibrous residue left after the extraction of sugarcane juice. Its main components are cellulose, hemicellulose and lignin. In recent years, scientists have actively explored its potential in producing high value-added chemicals and materials, gradually revealing its prospects for diverse applications. Sugarcane bagasse is considered an important raw material for biomass ethanol production. Through pretreatment, enzymatic hydrolysis and fermentation, cellulose and hemicellulose can be converted into fermentable sugars for use in the production of fuels such as bioethanol. In order to increase yield, methods such as alkali solution, acid solution or steam explosion are often used to pretreat sugarcane bagasse to reduce the lignin content and release fermentable sugars. Optimized pretreatment and fermentation processes can significantly increase ethanol production. In addition, bagasse can produce biodiesel, biogas and other high value-added chemicals such as xylitol, butyric acid and acetone-butanol-ethanol (ABE) solvents.
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