This thesis explores microbial D-xylose catabolism, its metabolic pathways and integration into biofuel production. D-xylose, a key sugar in lignocellulosic biomass which has significance for biofuel applications due to its abundance and potential as a sustainable energy source. This literature review highlights pathways such as the pentose phosphate and xylose isomerase pathways, detailing their biochemical roles in converting D-xylose into valuable products like bioethanol. Additionally, challenges like redox imbalances, enzyme efficiency, and genetic stability in engineered strains, with suggestions for metabolic optimization.