Acid hydrolysis of sawdust waste into bioethanol

A large amount of sawdust is generated as municipal waste in Ghana. The poor disposal of sawdust has led to high levels of contamination in the environment. In light of this, the study at hand focuses on the upcycling of sawdust waste (biomass) into bioethanol. The study framework followed three steps which include pretreatment and acid hydrolysis (H2SO4 and HCl at 0.6 M, 6 M, 11 M, and stock concentrations) followed by fermentation in a continuous stir tank reactor (CSTR). The material balance in the fermentation tank is principled on the following key species viz. yeast (Saccharomyces cerevisiae procured from the University of Cape Coast chemical stores), glucose, and ethanol. The highest yield from concentrated H2SO4 produced a glucose yield of 92.9% and ethanol yield of 80.9% after fermentation which was higher as compared to the HCl hydrolysates. To ascertain the purity of the ethanol yields, boiling point test, flammability test, chromic test, and GC–MS studies were carried out; 100 g of sawdust waste has been reported to yield 206 ml of bioethanol. The study concludes with a discussion of Ghana's potential of adopting, producing, and utilizing bioethanol. It also captures the benefit of bioethanol to the country and the future prospects of bioethanol production.