STUDIES ON THE SPECIFICITY OF THE FERMENTATION OF PENTOSES BY LACTOBACILLUS PENTOSUS

Abstract

Rates of acid production from glucose, xylose, ribose, L-arabinose, inosine, and uridine were detd. with resting cells grown with various sugars as the energy source. All cells formed acid rapidly from glucose and from the sugar present in the growth medium. Cells grown on xylose or L-arabinose fermented ribose rapidly; cells grown on ribose utilized the other pentoses poorly, if at all. All cells attacked ribose more rapidly than inosine or uridine. Acid was not formed from D-arabinose or hypoxanthine desoxy-riboside. Ribose-5-phosphate was degraded rapidly by extracts of cells grown on glucose, only slowly by extracts of cells grown on pentoses. D-xylose-5-phosphate, D-arabinose-5-phosphate, and free ribose were not degraded. It is suggested that D-xylose and L-arabinose are converted to compounds with the ribose configuration before cleavage of the pentose chain occurs.