Experimental evaluation of the use of gamma radiation in sugarcane bagasse (Saccharum spp.) as a pretreatment for bioethanol production

• Published in: Radiation physics and chemistry (Oxford, England : 1993) Vol. 218; p. 111611
• Main Authors: Varella, Leonardo Y.Z., Mesquita, Amir Z., de Rezende, Daniel B., Mourão, Isabel G., Cren, Érika C., Lopes, Nilva P., Silva, Walewska G., Alonso, Thessa C.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.05.2024
• Subjects: Gamma radiation; Pretreatment; Second-generation ethanol; Sugarcane bagasse; Gamma radiation; Pretreatment; Second-generation ethanol; Sugarcane bagasse
• ISSN: 0969-806X; 1879-0895
• DOI: 10.1016/j.radphyschem.2024.111611

Sugarcane bagasse was submitted to gamma radiation of Co-60 at the dose range of 0–2000 kGy, and the changes in its physical, chemical, morphological, and structural properties were studied. Results showed that the soluble sugars increased by 48% on exposure to ionizing radiation, with a drop in cellulose content from 37.4% to 18.1% at 2000 kGy. The crystallinity index also decreased. Despite all that, the soluble sugars, cellulose, and crystallinity showed an initial decrease in their content and index on initial doses (25–50 kGy), reorganizing at 100 kGy and falling again after higher doses (750–1000 kGy). Interestingly, the sample with the highest moisture content at 750 kGy, revealed a high formation of soluble sugars and a significant drop in crystallinity, suggesting a strong contribution of the humidity factor. Infrared spectroscopy (FTIR-ATR) showed a difference at around 900 cm−1 indicating the breakdown of glycosidic bonds in the lignocellulosic matrix. Scanning electron microscopy (SEM) illustrated the broken bagasse's physical structure as the dose increases, pointing to the delignification of the material, even though its content remained constant. This research shows that ionizing radiation on sugarcane bagasse not only starts the process of breaking down cellulose into glucose and other fermentable sugars but also makes it more accessible to enzymes during enzymatic hydrolysis, due to the rupture of its matrix, allowing a higher yield from this process. •Doses between 0 – 2000 kGy were applied for better behavior and understanding.•Physical, chemical, morphological, and structural analyses were performed.•There was an indication of moisture's impact on the material's radiolysis.•Despite material delignification, there was no major change in its content.•Experiments revealed gamma radiation's effective role in biomass pretreatment.