Metabolism of pectin in rumen bacteria Butyrivibrio fibrisolvens and Prevotella ruminicola

Cultures of Butyrivibrio fibrisolvens 787 and Prevotella ruminicola AR29 grown on pectin produced significantly more acetate and less butyrate, lactate, succinate and hydrogen than corresponding cultures grown on l -arabinose and d -glucose. In both bacteria, fermentation of pectin and arabinose yielded less lactate than fermentation of glucose. Pectin-grown cells of these strains possessed activity of 2-keto-3-deoxy-6-phosphogluconate aldolase (EC 4·1.2·14), an enzyme catalysing the pyruvate formation in the Entner–Doudoroff pathway. The activity of fructosediphosphate aldolase (EC 4·1.2·13) was found both in cells cultivated on glucose and on pectin. The phosphoketolase activity (EC 4·1.2·9) could not be detected in rumen bacterial strains studied.