Microbial degradation of 7-ketocholesterol

Jacques Mathieu, John Schloendorn, Bruce Rittmann, Pedro J J Alvarez

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


7-Ketocholesterol (7KC) is an oxidized derivative of cholesterol suspected to be involved in the pathogenesis of atherosclerosis and possibly Alzheimer's disease. While some oxysterols are important biological mediators, 7KC is generally cytotoxic and interferes with cellular homeostasis. Despite recent interest in preventing the accumulation of 7KC in a variety of matrices to avoid adverse biological effects, its microbial degradation has not been previously addressed in the peer-reviewed literature. Thus, the rate and extent of biodegradation of this oxysterol was investigated to bridge this gap. A wide variety of bacteria isolated from soil or activated sludge, including Proteobacterium Y-134, Sphingomonas sp. JEM-1, Nocardia nova, Rhodococcus sp. RHA1, and Pseduomonas aeruginosa, utilized 7KC as a sole carbon and energy source, resulting in its mineralization. Nocardia nova, which is known to produce biosurfactants, was the fastest degrader. This study supports the notion that microbial catabolic enzymes could be exploited to control 7KC levels in potential biotechnological applications for agricultural, environmental, or medical use.

Original languageEnglish (US)
Pages (from-to)807-813
Number of pages7
Issue number6
StatePublished - Nov 2008


  • 3β-Hydroxy-5-cholesten-7-one
  • 5-Cholesten-3β-ol-7-one
  • 7-Ketocholesterol
  • 7-Oxocholesterol
  • Oxysterol
  • Phytosterol

ASJC Scopus subject areas

  • Environmental Engineering
  • Microbiology
  • Bioengineering
  • Environmental Chemistry
  • Pollution


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