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Archives of Microbiology

, Volume 167, Issue 5, pp 269–274 | Cite as

Anaerobic mineralization of cholesterol by a novel type of denitrifying bacterium

  • J. Harder
  • Christina Probian
Original paper

Abstract

A novel denitrifying bacterium, strain 72Chol, was enriched and isolated under strictly anoxic conditions on cholesterol as sole electron donor and carbon source. Strain 72Chol grew on cholesterol with oxygen or nitrate as electron acceptor. Strictly anaerobic growth in the absence of oxygen was demonstrated using chemically reduced culture media. During anaerobic growth, nitrate was initially reduced to nitrite. At low nitrate concentrations, nitrite was further reduced to nitrogen gas. Ammonia was assimilated. The degradation balance measured in cholesterol-limited cultures and the amounts of carbon dioxide, nitrite, and nitrogen gas formed during the microbial process indicated a complete oxidation of cholesterol to carbon dioxide. A phylogenetic comparison based on total 16S rDNA sequence analysis indicated that the isolated micro-organism, strain 72Chol, belongs to the β2-subgroup in the Proteobacteria and is related to Rhodocyclus, Thauera, and Azoarcus species.

Key words Anaerobic bacteria Nitrate reduction Steroids Hydrocarbon Anaerobic degradation Azoarcus Thauera 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • J. Harder
    • 1
  • Christina Probian
    • 1
  1. 1.Abteilung Mikrobiologie, Max-Planck-Institut für Marine Mikrobiologie, Celsiusstrasse 1, D-28359 Bremen, Germany Tel. +49-421-2028-750; Fax +49-421-2028-580 e-mail: jens@postgate.mpi-mm.uni-bremen.deDE

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