A Review of the Bioethanol Production Process from Sugar and Lignocellulosic Base Materials and their Comparison

The concern about limited fossil resources has led researchers to use renewable and new energies. Bioethanol is one of the most important and widely used biofuels that can replace fossil fuels. Bioethanol can be produced from various agricultural products and waste, such as grains, molasses, fruit, lignocellulosic materials, and algae. Molasses, an amorphous sugar extracted from sugar cane and sugar beet, is considered one of the most essential raw materials of sugar base. Sugars are usually produced with Saccharomyces cerevisiae yeast and bio-ethanol. Starch-based materials, such as wheat and corn, must first be enzymatically hydrolyzed, and then bioethanol is obtained with the help of the fermentation process. Agricultural wastes such as cereal straw, sawdust, and black liquor are considered lignocellulosic raw materials. Lignocellulosic raw materials are first de-ligninized. Then, the enzymatic hydrolysis process is performed, and finally, with the help of fermentation, bioethanol is obtained. This review article first deals with the production status of this biofuel in the world's leading countries. Then, it briefly mentions the bioethanol production process from sugar, starch, and lignocellulosic raw materials and the challenges of each method. It also examines the types of yeasts and compares them and the effective parameters in the fermentation, pre-treatment, hydrolysis, and distillation processes.