This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Reddy, C. A. Articles by Wolin, M. J. Search for Related Content PubMed PubMed Citation Articles by Reddy, C. A. Articles by Wolin, M. J.

Characteristics of S Organism Isolated from Methanobacillus omelianskii¹

^a Departments of Dairy Science and Microbiology, University of Illinois, Urbana, Illinois 61803

ABSTRACT

Previous work showed that Methanobacillus omelianskii was a mixed culture of an ethanol-oxidizing organism called S organism and a hydrogen-utilizing methane bacterium, strain MOH. S organism grows poorly on ethanol unless a hydrogen-utilizing methanogenic bacterium is included to utilize the H₂ produced during growth. Further studies have shown that, among many substrates tested, only ethanol, n-propanol, n-butanol, isobutanol, n-pentanol, acetaldehyde, oxalacetate, and pyruvate are fermented by S organism, either alone or in combination with Methanobacterium ruminantium. It grew better in pure culture with pyruvate than with alcohols. H₂ gas phase inhibited growth on pyruvate as well as on alcohol. When grown alone on pyruvate, S organism produced mainly acetate, ethanol, and CO₂, in addition to a small amount of H₂. When combined with M. ruminantium, no H₂ and very little ethanol were produced and acetate production was increased. When M. ruminantium was present, electrons from pyruvate oxidation by S organism were channeled almost entirely to H₂ and hence to methane formation rather than ethanol. Also, S organism utilized more pyruvate when grown with M. ruminantium. Attempts to obtain better growth of S organism on ethanol by addition of many possible electron acceptors were unsuccessful. It grew best between 32 and 45 C, had a per cent guanine plus cytosine content of deoxyribonucleic acid bases of 47.27 ± 0.1, contained no cytochrome, and could be grown on a defined medium with pyruvate as the energy and carbon source and with (NH₄)₂SO₄ as the main nitrogen source. These and other results suggest that S organism belongs in a new genus, but assignment of a definite taxonomic status should await isolation and characterization of more strains.

² Present address: Department of Biochemistry, University of Georgia, Athens, Ga. 30601.

¹ This work was presented in part at the 69th Annual Meeting of the American Society for Microbiology, Miami, Fla., 4–9 May 1969.

This article has been cited by other articles:

• Sekiguchi, Y., Imachi, H., Susilorukmi, A., Muramatsu, M., Ohashi, A., Harada, H., Hanada, S., Kamagata, Y. (2006). Tepidanaerobacter syntrophicus gen. nov., sp. nov., an anaerobic, moderately thermophilic, syntrophic alcohol- and lactate-degrading bacterium isolated from thermophilic digested sludges.. Int. J. Syst. Evol. Microbiol. 56: 1621-1629 [Abstract] [Full Text]