Electron transport chains of lactic acid bacteria

R.J.W. Brooijmans

Research output: Thesisinternal PhD, WU

Abstract

Lactic acid bacteria are generally considered facultative anaerobic obligate fermentative bacteria. They are unable to synthesize heme. Some lactic acid bacteria are unable to form menaquinone as well. Both these components are cofactors of respiratory (electron transport) chains of prokaryotic bacteria.
Lactococcus lactis, and several other lactic acid bacteria, however respond to the addition of heme in aerobic growth conditions. This response includes increased biomass and robustness. In this study we demonstrate that heme-grown Lactococcus lactis in fact do have a functional electron transport chain that is capable of generating a proton motive force in the presence of oxygen. In other words, heme addition induces respiration in Lactococcus lactis. This aerobic electron transport chain contains a NADH-dehydrogenase, a menaquinone-pool and a bd-type cytochrome.
A phenotypic and genotypic screening revealed a similar response, induced by heme (and menaquinone) supplementation, in other lactic acid bacteria.
The genome of Lactobacillus plantarum WCFS1 was predicted to encode a nitrate reductase A complex. We have found that Lactobacillus plantarum is capable of using nitrate as terminal electron acceptor, when heme and menaquinone are provided. Nitrate can be used by Lactobacillus plantarum as effective electron sink and allows growth on a extended range of substrates. The impact of both the aerobic and anaerobic electron transport chain, on the metabolism and global transcriptome of Lactobacillus plantarum were studied in detail.
This work has resulted in the discovery of novel electron transport chains and respiratory capabilities of lactic acid bacteria. The potential respiratory capabilities of other, previously considered (strictly) anaerobic prokaryotic bacteria, were reviewed.









Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
  • Wageningen University
Supervisors/Advisors
  • de Vos, Willem, Promotor
  • Hugenholtz, J., Co-promotor, External person
Award date10 Nov 2008
Place of PublicationS.l.
Publisher
Print ISBNs9789085853022
Publication statusPublished - 2008

Keywords

  • electron transfer
  • lactic acid bacteria
  • lactococcus lactis
  • lactobacillus plantarum
  • haem
  • menaquinones

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  • Cite this

    Brooijmans, R. J. W. (2008). Electron transport chains of lactic acid bacteria. S.l.: S.n.