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Microbial degradation of 7-ketocholesterol
Jacques Mathieu1, John Schloendorn, Bruce E Rittmann
1Department of Civil and Environmental Engineering, Rice University, Houston, TX, USA.
Biodegradation
|March 18, 2008
Summary
Microbial degradation of 7-ketocholesterol (7KC), a cholesterol derivative linked to diseases, was investigated. Several soil bacteria, including Nocardia nova, efficiently mineralized 7KC, suggesting biotechnological applications.
Area of Science:
- Microbiology
- Biochemistry
- Environmental Science
Background:
- 7-Ketocholesterol (7KC) is an oxidized cholesterol derivative implicated in atherosclerosis and Alzheimer's disease pathogenesis.
- While some oxysterols are bioactive, 7KC exhibits cytotoxicity and disrupts cellular homeostasis.
- Preventing 7KC accumulation is of interest, but its microbial degradation remains uncharacterized.
Purpose of the Study:
- To investigate the rate and extent of 7-ketocholesterol (7KC) biodegradation by microorganisms.
- To identify bacterial species capable of utilizing 7KC as a sole carbon and energy source.
- To explore potential biotechnological applications for microbial 7KC degradation.
Main Methods:
- Screening of diverse bacterial isolates from soil and activated sludge for 7KC degradation.
- Culturing bacteria with 7KC as the sole carbon and energy source.
- Monitoring 7KC mineralization by identified bacterial strains.
Main Results:
- Multiple bacterial strains, including Proteobacterium Y-134, Sphingomonas sp. JEM-1, Nocardia nova, Rhodococcus sp. RHA1, and Pseudomonas aeruginosa, effectively degraded 7KC.
- These bacteria utilized 7KC as their sole source of carbon and energy, leading to its complete mineralization.
- Nocardia nova demonstrated the highest degradation rate among the tested species.
Conclusions:
- Microbial communities possess the capability to degrade 7-ketocholesterol (7KC).
- Specific bacterial strains, notably Nocardia nova, can efficiently mineralize 7KC.
- Microbial catabolic enzymes offer potential for biotechnological control of 7KC levels in various applications.
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