Eco-friendly sodium carbonate pretreatment of sugarcane leaves for enhanced enzymatic saccharification

Sodium carbonate (Na2CO3) is a mild alkali-based pretreatment for lignocellulose, making it an eco-friendly method. In this study, sugarcane leaves (ScL), an agricultural waste product from Thailand, were pretreated using various Na2CO3 solutions combined with different heat treatments: a water bath (at 80 degrees C for 3 h) and laboratory autoclaving (at 121 degrees C for 1 h). The results showed higher cellulose content (44.26-50.29%) and lower lignin content (12.33-13.00%) in the ScL pretreated with Na2CO3-autoclaving compared to untreated biomass. Physicochemical characterization were conducted using Fourier transform infrared (FTIR) spectroscopy, X-ray powder diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) analyses. Significant structural changes were observed in the functional groups, crystallinity index (CrI), morphological features, and thermal properties of the ScL after Na2CO3 pretreatment conditions. The 0.5 M Na2CO3-autoclaving pretreatment produced a high sugar yield of 80.80% with an enzyme loading of 15 FFU/g after 72 h of enzymatic hydrolysis, outperforming both the untreated samples and other pretreatment conditions. Overall, this study highlights an approach by combining Na2CO3 with controlled heat treatments, specifically autoclaving, to enhance the pretreatment of sugarcane leaves, an agricultural waste, thereby improving cellulose accessibility, lignin removal, and sugar yield in an eco-friendly manner. Further studies are needed to optimize the pretreatment process.