Microbial Steroid Metabolism
Steroids are ubiquitous in the environment and are significant growth substrates for microorganisms. Metabolism of steroids is also important for some pathogens like Mycobacterium tuberculosis, the causative agent of tuberculosis, as well as for biotechnical applications. We are studying bacterial steroid degradation using a combination of (i) culture-based molecular genetic and biochemical studies and (ii) culture-independent analyses of bacterial genomes and environmental metagenomes.
Currently, we are investigating how steroid-degrading bacteria like Rhodococcus jostii access water-insoluble steroid substrates like cholesterol, which normally occur in biological membranes. We are using a liposome-based model system with R. jostii and mutant strains. In addition, we are developing tools to explore bacterial genomes and environmental metagenomes for genes encoding steroid catabolism pathways in order to expand our knowledge of the diversity of steroid catabolism and the roles of steroid-degraders in diverse ecosystems.