CARBOHYDRATE METABOLISM OF ORGANISMS OF THE GENUS MYCOBACTERIUM

Abstract

None of the Mycobaderium spp. studied produced acid in carbohydrate broth. Reaction curve determinations gave no definite information as to extent of carbohydrate utilization. A rather wide utilization was shown by direct quantitative carbohydrate determinations. All cultures became progressively more alkaline with an associated increase in NH3 content. There was no evidence that any products were formed from carbohydrate cleavage that influenced the reaction. Presence of utilizable carbohydrates thus exerted an effect on reaction only to the extent that they altered protein cleavage. Less NH3 was produced incident to the production of a given amount of growth in presence of utilizable carbohydrates, a protein-sparing action thus being indicated. There was a gradual decrease in carbohydrate until it completely disappeared. The CO2 produced varied directly with growth and with carbohydrate utilized. In most cases more CO2 was recovered than could have been derived from carbohydrate lost. This contrasts with the 10-18% yield of possible CO2 from cultures of acid-forming organisms such as Bacillus coli. The mycobacteria could not be grown in absence of molecular O and no utilization of carbohydrates could be demonstrated under such conditions. The evidence indicates that if the carbohydrate molecule is attacked at all it is completely oxidized, no intermediate cleavage products appearing in the media.