Four Molybdenum-Dependent Steroid C-25 Hydroxylases: Heterologous Overproduction, Role in Steroid Degradation, and Application for 25-Hydroxyvitamin D Synthesis.

Side chain-containing steroids are ubiquitous constituents of biological membranes that are persistent to biodegradation. Aerobic, steroid-degrading bacteria employ oxygenases for isoprenoid side chain and tetracyclic steran ring cleavage. In contrast, a Mo-containing steroid C-25 dehydrogenase (S25DH) of the dimethyl sulfoxide (DMSO) reductase family catalyzes the oxygen-independent hydroxylation of tertiary C-25 in the anaerobic, cholesterol-degrading bacterium Its genome contains eight paralogous genes encoding active site α-subunits of putative S25DH-like proteins.

Engineering a bzd cassette for the anaerobic bioconversion of aromatic compounds.

Microorganisms able to degrade aromatic contaminants constitute potential valuable biocatalysts to deal with a significant reusable carbon fraction suitable for eco-efficient valorization processes. Metabolic engineering of anaerobic pathways for degradation and recycling of aromatic compounds is an almost unexplored field. In this work, we present the construction of a functional bzd cassette encoding the benzoyl-CoA central pathway for the anaerobic degradation of benzoate.

The ICE of Azoarcus sp. CIB, an integrative and conjugative element with aerobic and anaerobic catabolic properties.

Integrative and conjugative elements (ICE) play a major role in aerobic degradation of aromatic compounds, but they have not yet been shown to be involved in anaerobic degradation. We have characterized here the ICE element which endows to the beta-proteobacterium Azoarcus sp. CIB with the ability to utilize aromatic hydrocarbons.

Degradation of cyclic diguanosine monophosphate by a hybrid two-component protein protects Azoarcus sp. strain CIB from toluene toxicity.

Cyclic diguanosine monophosphate (c-di-GMP) is a second messenger that controls diverse functions in bacteria, including transitions from planktonic to biofilm lifestyles, virulence, motility, and cell cycle. Here we describe TolR, a hybrid two-component system (HTCS), from the β-proteobacterium Azoarcus sp. strain CIB that degrades c-di-GMP in response to aromatic hydrocarbons, including toluene.

Whole-genome analysis of Azoarcus sp. strain CIB provides genetic insights to its different lifestyles and predicts novel metabolic features.

The genomic features of Azoarcus sp. CIB reflect its most distinguishing phenotypes as a diazotroph, facultative anaerobe, capable of degrading either aerobically and/or anaerobically a wide range of aromatic compounds, including some toxic hydrocarbons such as toluene and m-xylene, as well as its endophytic lifestyle. The analyses of its genome have expanded the catabolic potential of strain CIB toward common natural compounds, such as certain diterpenes, that were not anticipated as carbon sources.