Microaerobic and anaerobic metabolism of a Methylocystis parvus strain isolated from a denitrifying bioreactor

M. Vecherskaya, C. Dijkema, H. Ramirez Saad, A.J.M. Stams

Research output: Contribution to journalArticleAcademicpeer-review

23 Citations (Scopus)

Abstract

An obligate methanotrophic bacterium, strain MTS, was isolated from a methane-fed microaerobic denitrifying bioreactor. 16S rRNA and DNA–DNA hybridization analysis revealed that this organism was most closely related to Methylocystis parvus, a Type II methanotroph, belonging to the a-subclass of the Proteobacteria. The metabolism of the bacterium under microaerobic and anaerobic conditions was studied by 13C-NMR. 13C-labelled poly-ß-hydroxybutyrate (PHB) formation occurred in cell suspensions incubated with 13C-labelled methane at low (5–10%) oxygen concentration. Under these conditions low levels of succinate, acetate and 2,3-butanediol were formed and excreted into the culture medium. Intracellular PHB degradation was observed in intact cells under anaerobic conditions in the absence of an exogenous carbon source during a long-term incubation of 90 days. Multiple 13C-labelled ß-hydroxybutyrate, butyrate, acetate, acetone, isopropanol, 2,3-butanediol and succinate were identified as products in in vivo13C-NMR spectra and in the spectra of culture medium during the dynamic PHB degradation. The isolated obligate methanotroph clearly shows a fermentative metabolism of PHB under anaerobic conditions. The excreted products may serve as substrates for denitrifying bacteria
Original languageEnglish
Pages (from-to)442-449
JournalEnvironmental Microbiology Reports
Volume1
Issue number5
DOIs
Publication statusPublished - 2009

Keywords

  • methane-dependent denitrification
  • external carbon source
  • methanotrophic bacteria
  • renaturation rates
  • dna hybridization
  • acid
  • community
  • sequence
  • sediments
  • oxygen

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