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 Google Scholar Google Scholar Articles by Evans, J. D. Articles by Martin, S. A. Search for Related Content PubMed PubMed Citation Articles by Evans, J. D. Articles by Martin, S. A. Agricola Articles by Evans, J. D. Articles by Martin, S. A.

 Previous Article  |  Next Article 

Appl. Environ. Microbiol., 12 1997, 4853-4858, Vol 63, No. 12
Copyright © 1997, American Society for Microbiology

Factors affecting lactate and malate utilization by Selenomonas ruminantium

JD Evans and SA Martin
Department of Animal and Dairy Science, The University of Georgia, Athens 30602-2771, USA. scottm@uga.cc.uga.edu

Lactate utilization by Selenomonas ruminantium is stimulated in the presence of malate. Because little information is available describing lactate-plus-malate utilization by this organism, the objective of this study was to evaluate factors affecting utilization of these two organic acids by two strains of S. ruminantium. When S. ruminantium HD4 and H18 were grown in batch culture on DL-lactate and DL-malate, both strains coutilized both organic acids for the initial 20 to 24 h of incubation and acetate, propionate, and succinate accumulated. However, when malate and succinate concentrations reached 7 mM, malate utilization ceased, and with strain H18, there was a complete cessation of DL-lactate utilization. Malate utilization by both strains was also inhibited in the presence of glucose. S. ruminantium HD4 was unable to grow on 6 mM DL-lactate at extracellular pH 5.5 in continuous culture (dilution rate, 0.05 h-1) and washed out of the culture vessel. Addition of 8 mM DL-malate to the medium prevented washout on 6 mM DL- lactate at pH 5.5 and resulted in succinate accumulation. Addition of malate also increased bacterial protein, acetate, and propionate concentrations in continuous culture. These results suggest that 8 mM DL-malate enhances the ability of strain HD4 to grow on 6 mM DL-lactate at extracellular pH 5.5.