摘要:Cell free extracts from a wide variety of Gram-negative, anaerobic, non-sporeforming rods were screened for dehydrogenase enzymes of carbohydrate and nitrogen metabolism. Four enzymes, malate dehydrogenase, glutamate dehydrogenase, glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase, were found to be of diagnostic importance. The ‘Bacteroides fragilis’ group possessed all four enzymes whereas the ‘B. melaninogenicus-B. oralis’ group and the asaccharolytic, pigmented species were characterised by the presence of only malate and glutamate dehydrogenases. The saccharolytic and asaccharolytic pigmented species could be differentiated by the wide difference in pH optimum for malate dehydrogenase. Fusobacterium species and Leptotrichia buccalis both possessed only glutamate dehydrogenase, but there were differences in enzyme activity between both taxa. Other genera such as Anaerorhabdus, Megamonas, Mitsuokella. Rikenella, Sebaldella and Tissierella had characteristic enzyme profiles. These enzymatic data are of diagnostic value within the Bacteroidaceae and may serve as useful markers for studying the ecological interrelationships of these bacteria.Keywords: Bacteroidaceae; Dehydrogenases; Enzyme patterns.