Abstract
The demand for bioethanol has been steadily growing over fossil fuels due to lower greenhouse gas emissions, improved energy security, and rural development opportunities. Bioethanol can be produced from a variety of feedstocks, including corn, sugarcane, wheat, and other biomass sources, which can be categorized into 1G (sugar and starch crops) and 2G (lignocellulosic biomass). Although most of the ethanol produced in the United States is by using corn starch, there is a substantial need to expand the type of substrates to increase the overall ethanol production without competing with food, land, and water resources. This chapter presents a concentrated analysis of 1G and 2G ethanol production processes, honing in on the refinement of efficiency through genetic engineering, with a specific emphasis on enhancing xylose uptake in Saccharomyces cerevisiae for conversion to ethanol. Furthermore, it evaluates the cost-effectiveness and environmental implications associated with diverse bioethanol production techniques aiming to identify the most sustainable and economically viable options.