Mechanism of Reduction of Aqueous U(V)-dpaea and Solid-Phase U(VI)-dpaea Complexes: The Role of Multiheme -Type Cytochromes.

The biological reduction of soluble U(VI) complexes to form immobile U(IV) species has been proposed to remediate contaminated sites. It is well established that multiheme -type cytochromes (MHCs) are key mediators of electron transfer to aqueous phase U(VI) complexes for bacteria such as MR-1. Recent studies have confirmed that the reduction proceeds via a first electron transfer forming pentavalent U(V) species that readily disproportionate.

Biological Reduction of a U(V)-Organic Ligand Complex.

Metal-reducing microorganisms such as MR-1 reduce highly soluble species of hexavalent uranyl (U(VI)) to less mobile tetravalent uranium (U(IV)) compounds. The biologically mediated immobilization of U(VI) is being considered for the remediation of U contamination. However, the mechanistic underpinnings of biological U(VI) reduction remain unresolved.

Production of jet fuel precursor monoterpenoids from engineered Escherichia coli.

Monoterpenes (C isoprenoids) are the main components of essential oils and are possible precursors for many commodity chemicals and high energy density fuels. Monoterpenes are synthesized from geranyl diphosphate (GPP), which is also the precursor for the biosynthesis of farnesyl diphosphate (FPP). FPP biosynthesis diverts the carbon flux from monoterpene production to C products and quinone biosynthesis.