Harnessing Municipal Solid Waste: Enzymatic Pathways to Bioethanol Sustainability: A Review

Abstract— Waste management problems and the need for renewable energy can be addressed by utilizing municipal solid waste for bioethanol production as a renewable feedstock. The enzymatic hydrolysis process of turning solid waste into fermentable sugars for the subsequent production of bioethanol is the main focus of the current study. Enzyme access is significantly facilitated by effective pretreatment, particularly the alkali process with NaOH, which breaks the resistant lignocellulosic structure. Hydrolysis is possible under moderate circumstances (40–50°C, pH 4.5–5.0) thanks to fungal-derived cellulolytic enzymes from Aspergillus and Trichoderma strains. Using ethanologenic yeasts such as Saccharomyces cerevisiae and Pichia stipitis, the sugar-containing hydrolysate is then fermented, with optimised procedures producing ethanol. It has been discovered that integration approaches to the process, like simultaneous fermentation and saccharification, increase efficiency compared to independent operating steps. Despite promising results, problems with process optimisation, biomass recalcitrance, and enzyme cost persist. Enzymatic hydrolysis is used in this study as an example of a possible method for turning municipal waste into bioethanol; however, further technological advancements are required to increase the economic feasibility and commercial use of this environmentally friendly bioconversion process.