AMINO ACID FERMENTATION BY FUSOBACTERIUM NUCLEATUM

Fusobacterium nucleatum (Fusobacterium fusiforme) is a weakly saccharolytic gram negative anaerobic rod which is indigenous to the oral cavity of man. This organism fermented aspartate, cysteine, glutamate, glutamine, histidine, lysine, methionine, serine and threonine forming butyrate and acetate as the main acid end products. The presence of glucose in the medium did not prevent amino acid fermentation as the amino acids and glucose were catabolized concurrently. The butyrate and acetate found in spent glucose-trypticase broth were derived primarily from the broth amino acids, whereas lactate and formate arose from glucose catabolism. The absence of glucose catabolite repression could be accounted for by the slow degradation of glucose i.e. 15-25 μg glucose utilized/mg dry cell weight/hr. The fermentation of lysine did not involve significant decarboxylation but rather appeared to be by a pathway which involved cleavage into butyrate and acetate. © 1968.