Jonathan Lloyd School of Earth, Atmospheric and Environmental Sciences The University of Manchester Geomicrobiology.co.uk Land Bioremediation and Bionanotechnology Industrial Uses of Bacteria 19 May IOM 3, London

Plan Introduction to “Geomicrobiology” & “Bionanotechnology” Nanomaterials for remediation Microbial iron cycling and the production of functional nanomaterials –Bionanomagnetite production –Incorporation of trace elements; Co ferrites –Treatment of metals (Cr(VI)/Tc(VII)) –Treatment of organics (azo dyes, nitrobenzene, TCE) –Novel, multifunctional catalysts with precious metal coatings Future research

Geomicrobiology Microbial ecology Microbial physiology Biochemistry Molecular biology Systems biology Geochemistry Inorganic chemistry Mineralogy Isotope chemistry Environmental/civil engineering Biology Science / engineering Geomicrobiology “The role microbes play or have played in geological processes” Ehrlich, 1996 PhysicsComputation

Geomicrobiology Includes The origin of life Life on other planets The control of Earth’s chemistry Environmental mobility of metals, radionuclides and organics Bioremediation Bionanotechnology

Nanotechnology “engineering and manufacturing at nanometer scales, with atomic precision” Bionanotechnology “subset of nanotechnology; atomic level engineering and manufacturing using biological precedents for guidance” Goodsell (2004) “Bionanotechnology: Lessons from Nature” Emphasis; vision of precision assembly of complex large-scale systems incorporating biomolecular devices. Interfaces with “Synthetic Biology” Manchester Geomicrobiology Group has focused on engineering biominerals to augment bioremediation potential of subsurface bacteria

Environmental nanotechnology

Environmental Bionanotechnology

Dissimilatory metal reduction Focus of Manchester Geomicrobiology group Mechanisms Environmental impact Biotechnological applications

Microbial metal reduction Widely distributed through prokaryotic world Transition metals, metalloids, actinides Dissimilatory and resistance processes

Metal reduction; mechanisms Electron transfer mechanisms in Fe(III)-reducing bacteria e.g. Geobacter (proteins, genes, secreted mediators) Mechanisms of reduction of trace elements and radionuclides Development of molecular scale model for electron transfer to mineral surfaces

Metal reduction; environmental impact From Islam et al Nature Mobilisation of As(III) by metal-reducing bacteria

Metal reduction; environmental impact Biogeochemistry of radionuclides Organics or H 2 CO 2 and/or H 2 O Soluble U(VI) Insoluble U(IV) e- Drigg nuclear repository

Functional bionanominerals Bionano-ferrite spinels – ‘designer’ nanomagnets Precious metal (Pd, Ag, Au) and Fe-based catalytic bionanoparticles Bionano-chalcogenides - diluted magnetic semiconductors and quantum dots Pd Magnetite supported Bionano magnetite catalyst

Why are magnetic nanoparticles important? magnetic data storage catalysis biosensors drug delivery cancer therapy magnetic resonance imaging (MRI) environmental remediation

Magnetite bioproduction Geobacter sulfurreducens Examples with trace metals added to system during or after magnetite production

Incorporation of trace elements Bioengineering Co ferrites

X-ray Magnetic Circular Dichroism Element, site and symmetry selective ; quantitative information on site occupancies in magnetic minerals. Inverse spinel structure of magnetite is Fe 3+ [Fe 2+ Fe 3+ ]O 4 (see left). tet=tetrahedral, oct=octahedral site. Possible to substitute Fe 2+ with other transition metals (and change the magnetic properties of the spinel) Octahedral sites Tetrahedral sites Oxygen Fe 2+ Oct Fe 3+ Tet Fe 3+ Oct Tet[oct] Fe 0.97 [Fe 2.03 ]O 4 Occupancies of Geobacter magnetite

Geobacter sulfurreducens Cobalt-substituted magnetites