Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. D-Xylose is a five-carbon aldose (pentose, monosaccharide) that can be catabolized or metabolized into useful products by a variety of organisms. There are at least four different pathways for the catabolism of D-xylose: An oxireductive pathway that is present in eukaryotic microorganisms, an isomerase pathway, and two oxidative pathways that are called Weimberg and Dahms pathway are common in prokaryotic microorganisms.