Hydrothermal pretreatment of sugarcane bagasse pith for biogas production and digestate valorization to biochar.

Sugarcane bagasse pith is generated as waste from bagasse-based paper industries which is still underutilized and mostly burnt as fuel in boilers. Therefore, an integrated pathway for the value-addition of the pith is explored. In the present study, hydrothermal pre-treatment of pith through response surface methodology and C/N was optimized for enhanced biogas production. At optimized conditions, a maximum biogas yield of 474.3 mL/gVS with ∼55% methane was attained with cellulose and reducing sugar of 59.2% and 3.68 g/L respectively. A severity factor of 3.8–4 was found suitable for cellulose enrichment, reducing sugar and biogas production, and at higher severity, a reduction in the above parameters was observed. Moreover, the digestate-based biochar delivered the highest biochar yield and surface area of 75.8 wt% and 254.47 m2/g respectively. This study is the first of its kind where the bagasse pith has been explored in a biorefinery approach to achieve circularity. [Display omitted] • Integrated biorefinery approach in Pith valorization to achieve circularity. • Severity factor of 3.8–4 during pretreatment was suitable for the anaerobic digestion. • The maximum biogas yield was found to be 474.3 mL/gVS with ∼55% methane content. • Highest yield of biochar was obtained at 400 ℃ and at 10% moisture content. • Biochar at 800 ℃ and 80% moisture delivered the highest surface area of 254.47 m2/g. [ABSTRACT FROM AUTHOR]