The isolation of glycerol-fermenting and lipolytic bacteria from the rumen of the sheep.

Abstract

SUMMARY: Facultatively anaerobic bacteria appear to play little part in glycerol fermentation in the sheep rumen. Amongst the most important members of the glycerol-fermenting flora are strict anaerobes of the group Selenomonas ruminantium var. lactilyticas. Three isolates of a different group of strictly anaerobic curved Gram-negative rods, which hydrolyse linseed oil and tributyrin as well as fermenting glycerol, were obtained in numbers which suggest they are amongst the more important lipolytic bacteria in the rumen. The main product of fermentation of glycerol by the seleno-monads and the lipolytic bacteria is propionic acid, but other acids are also formed. The properties of these bacteria and some others isolated during the experiments are described. All the bacteria appear to be normal inhabitants of the rumen of sheep fed a number of different rations. The numbers of these organisms were not appreciably increased by feeding glycerol or triglycerides to the animals.