The Fermentation of Inositol by Propionibacterium Pentosaceum

Abstract

The relationship of mee8o-inositol to glucose has been a subject of interest since Fischer (1944-1945) suggested that a biological equilibrium could exist between the two. Of those authors claiming a biological synthesis of one from the other, all have used a system utilizing either animals or plants (Stetten and Stetten, 1946; Kursanov et al., 1949a, 1949b; Fernandez et al., 1944, 1945). These results have indicated that inositol could give rise to glucogenic substances or that inositol could be formed from glucogenic substances, but in no case has evidence been presented to demonstrate a direct equilibrium between inositol and glucose. Volk and Pennington (1951) demonstrated that the end products of inositol and glucose from a species of Aerobacter differed inasmuch as no 2,3-butylene glycol was formed in the fermentation of inositol. They concluded from this that glucose or the usual phosphorylated hexoses were not intermediates in the fermentation of inositol by this organism. The present work with Propionibaderium pentosaceum provides additional evidence that glucose is not an intermediate in the fermentation of inositol. METHODS The end products from the fermentation of both glucose and inositol by Propionibacterium pentosaceum, strain E.2.1.4.,8 were determined. Cells were grown in a medium consisting of the salt solution used by Volk and Pennington (1951) with the addition of 0.5 per cent yeast extract, 0.1 per cent sodium thioglycolate, 1.0 per cent glucose or inositol, and 10 per cent 0.1 M Sorensen's phosphate buffer, pH 6.8. The cells were grown for three to four days at 30 C in 2-liter Erlenmeyer flasks containing 1,500 ml of media. Cellular suspensions were prepared by centrifuging, washing once with tap water, and suspending the