Comparative assessment of sugarcane bagacillo and bagasse at lab-scale for production of sugars and green chemicals via biochemical platform

The sugarcane-driven industry can exemplify sustainable waste management by valorizing its lignocellulosic streams and boosting the rural economy by product diversification. In this aspect, bagacillo is a promising yet untapped carbonaceous feedstock, representing fine fraction of sugarcane bagasse (SCB) with low bulk density. It is used either as a filter aid for juice clarification, when added to mud or mixed with bagasse for cogeneration. This study explores bagacillo for the production of sugars and green chemicals using biochemical platform, with SCB as the benchmark. Its NaOH pretreatment preserved > 90 and > 70% glucan and xylan in solid fraction. Fed-batch hydrolysis with Cellic CTec3 at 1-kg scale liberated 167.4 ± 1.87 and 183.53 ± 1.23 g L monomeric sugars in filtrates of bagacillo and SCB, respectively, in 48 h. Its high-ash content reduced glucan conversion yields by 16%, and led to glucan under-estimation in residual biomass during mass balance closure. Irrespective of feedstock type, within 18 h Saccharomyces cerevisiae MTCC 180 and Pachysolen tannophilus MTCC 1077 produced ~ 5% (v/v) ethanol from 1.5L glucose-rich filtrates, with a ~ 18-fold enhancement in biomass accumulation. However, when Bacillus coagulans NCIM 5648 was assessed for high-temperature 2G lactic acid production, the obtained titer from bagacillo-derived hydrolysate (33.6 ± 1.23 g L) was lower than SCB (43.38 ± 1.89 g L). The present study demonstrated that bagacillo is an equally amenable bioresource as ~ 506 g fermentable sugar was extracted from 1-kg raw biomass and its glucose-rich fraction showed feasibility for microbial transformation to bio-based platform chemicals.