Biobutanol Feedstock Enhancement: Extract Fermentable Sugar from Sugarcane Bagasse via Alkaline Pretreatment and Steam Hydrolysis

This research focuses on the enhancement of biobutanol production through Clostridium spp. and its mutants by using agricultural waste as carbon source. The fermentable sugar was extracted from sugarcane bagasse using alkaline pretreatment and steam hydrolysis. The agricultural waste, rich in cellulose, undergoes NaOH-based alkaline pretreatment, effectively removing lignin at a low cost. Subsequent steam hydrolysis results in increasing glucose concentrations across multiple rounds, with maximum hydrolysis observed in round 2, yielding of reducing sugar 16.88% (25.32 g/L). This work evaluates different media types for biobutanol production, comparing commercial glucose (media type I) with hydrolysed sugar (media type II). Both wild-type (WT) and mutant strains are utilised, with strain 45–20 exhibiting the highest butanol concentration in media type II. Economic analysis reveals that NaOH pretreatment incurs a cost of 0.66 USD/L of hydrolysis, offset by a benefit of 0.80 USD based on the value of reducing sugar. Steam hydrolysis from round 1 to round 2 yields 48.24 g/L, resulting in an additional benefit of 1.1 USD. Importantly, the study establishes the feasibility of non-toxic conditions for alkaline pretreatment and hydrolysis, making the overall process economically viable. These findings underscore the potential of utilizing sugarcane bagasse as a valuable resource for sustainable biobutanol production under cost-effective conditions.