Unit of Functional BionanomaterialsSchool of Biosciences

Mark D. Redwood, Kevin Deplanche, Angela Murray, Iryna P. Mikheenko, Ping Yong, Neil J. Creamer, Rafael Orozco, Oluwakemi Lowal, Lynne E Macaskie.

19th May 2010

Prof Lynne E Macaskie

Applied Microbiolo

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Applied Microbiolo

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Bio-energy

Bio-remediation

Bio- nanocatalyst

Making bioenergyEscherichia coliRhodobacter sphaeroides ; capsulatusMaking bionano catalystDesulfovibrio desulfuricans ; fructosovoransEscherichia coliRalstonia, Rhodobacter spp, Micrococcus spp.,

Shewanella, Geobacter, Arthrobacter(Making ion exchangers)

DarkFermentation

Photo-Fermentation

Sugarywastes

H2

Organicacids

UK [food industry + domestic] = 24 M tpa

Potential to produce 280 M kg of bio-H2

Energy value: 5.6 TWh (terawatthour) and heat

13% of 2020 target◦ 15% renewable sources.

Total waste is ~110 M tpa inc. agricultural and sewage

Unique combination of advantages:◦ Renewable/sustainable energy sources

Organic matter and sunlight◦ Inherently free of fuel cell poisons

CO, H2S

◦ Waste disposal Food waste Agricultural residues

◦ Simple/cheap process Ambient temperature & pressure

Bench scale (1ml-20L) Pilot scale (120 L)

Ideally:1 Glucose 2 H2 + 1 acetate + 1 ethanol + 2 CO2

We select E. coli because◦ Fast aerobic growth◦ Tolerance to O2 during anaerobic fermentation

◦ Best tolerance to H2 partial pressure◦ No sporulation◦ Best-characterised genetic background for GM

E.g. removal of uptake hydrogenases◦ ‘electrotolerance’

AnionCation

Anion-selectivemembrane

Electrodialysis uses an anion selective membrane and direct current

Organic acids cross the membrane due to negative charge

FermentationConcentratedorganicacids

- +

+/-

WasteFruit

Manual chopping

1st Press

Juice

Pressings Wash

Water

Infusion

2nd press Washed Pressings

Hot Compressed Water (HCW)

Hydrolysate

Detoxification

Fermentation

Water

Stones Insolubles and by-

products

Solid residues

Organic acids H2 + CO2

Anoxygenic photosynthesis

Purple non-sulphur bacteria◦ Rhodobacter spp.

High yield, broad substrate range◦ e.g. Lactate 6 H2

H2 produced by Nitrogenase enzyme◦ Very sensitive to NH4

+

◦ Select wastes with high C/N

Light conversion efficiency◦ Up to ~5%

Logging equipment for light intensity and temperature.

250 ml 250 ml reactors + reactors + water-water-jacketjacket

March, June and October

Water heater pumps 30 °C water to the jackets

Tubular arraySimulates 0.5 m2 of sunlit

areaVolume : up to 50 LLamps deliver

programmed light patterns

Simulates any location or season

Equatorial

UK

Equatorial

UK

MethodNet energy / areakWh/day/hectare

Source

UoB’s bio hydrogen 670 (UK) (+ gate fees)Biowaste2energy

Photovoltaics (PV) 665 (Bavaria)Bavaria Solarpark

Wind 480 (UK, on shore) MacKay (2009)

Anaerobic Digestion (AD) 425 (+ gate fees)Vagron, Netherlands*

Crop-derived bio-fuels ~120 (UK) MacKay (2009)

Alga-derived bio-diesel Purportedly better than crops

* Including parasitic energy and total site area. Published values use the raw energy generated and only the space occupied by the digester.

When Biology meets Nanotechnology◦ Reduction of metal precursors using bacterial

enzymes yields highly active nanoparticles (NPs) at the cell surface

Bacterial cell

Bacteria concentrate precious metals

Hydrogenase enzymes

2H+ + Pd0(s)

Palladised cells of D. desulfuricans

Nanoparticles grow and erupt from the cells

Stabilised nano-Pd(0) crystals

bound to cells. Similar results with Pt(0)

Atom-scale resolution shows crystal structure; faces are

clearly visible (5 nm Pd-nanoparticle)

Biocatalyst manufacture process optimised for PGMs◦Pd, Pt, Au

Monometallic and bimetallic Manufacture can be coupled to biorecovery of

metals from wastes◦‘Green chemistry’◦Lower the threshold of economic recovery of

PGMs

Advantages over conventional chemical catalysts◦Cheap(er), “green” manufacturing process◦Easy to scale up◦Excellent monodispersity of NPs◦Bacterial support doesn’t leach metals◦Can be recycled◦Exhibit different properties from chemical

catalysts◦Active in a broad range of reactions

Manufacture of platform chemicals◦ Selective hydrogenations (Pd, Pt)

E.g. Heck coupling (pharma)◦ Selective oxidations (Au, Au/Pd)

Perfume industry, food additives… ◦ Remediation of recalcitrant compounds (TCE)◦ Green energy

Conversion of biodiesel wastes (glycerol-Au) Automotive catalysts

Reduction of pollutant emissions (CO, NOx) Improvement of performances

Fuel cells electrocatalysts (PEMFC)

Tested catalyst by recycling in a series of reactions

Compared selectivity and conversion

With Pd/C, rate drops substantially with each run Key feature of BioPd: increased recyclability – shelf life

CO chemisorption experiments shows bio-Pd contains much smaller Pd particles than Pd/C

Bio-Pd Pd/C

Metal Dispersion (%) 67 3

Metallic Surface Area(m²/g sample)

15 0.6

Metallic Surface Area:(m²/g metal)

297 11

Active Particle Diameter (nm)

2 45

Why is there a difference in activity between bio-Pd and Pd/C? Smaller particles; greater proportion of corner atoms and adatoms

more active in Heck coupling (Augustine et al., J. Mol. Cat. A., 1995, 95, 277-285)

corner atom

adatom

bacterial cell Pd(II) Pd(0)

Soluble Pd(II) complexes are the catalytic species1. Solid Pd(0) Soluble Pd(II) complexes2. catalyses Heck coupling3. Pd(II) Pd(0) at the end of the cycle

bacterial cell

Pd(II) Pd(0)

Carbon Carbon

The Pd particles may redeposit on the support’s surface directly on top of other Pd particles already on the support

Pd particles reform on other Pd particles, thus the particle size grows

Zhao et al., J. Mol. Cat. A., 2002, 180, 211-219

BioPd maintains small particle size through 6 runs Initially smaller particles Redeposition onto biomass

Pd(II) Pd(0)

Carbon Carbon

Bimetallic catalyst with high numbers of Au core/Pd shell NPs

500 nm

HAADF analysisTEM analysis

Benzyl alcohol Benzyl aldehyde

Toluene

Benzene

Benzoic acid

Benzyl benzoate

Selective oxidation of benzyl alcohol to benzaldehyde

High constant selectivity towards benzylaldehyde

Work in progress on a range of alcohols

5% Pd/C

Area of Research

Recovery of Platinum Group Metals

from Secondary Sources

Physical Processing to

Upgrade Metals

Chemical Leaching to

Solubilise Metals

Recovery of Metals using

Bacteria

Added Value End Product

Incinerator Ash Road Dust Industrial Slag Materials Electronics scrap

Electrostatic SeparationElectrostatic separations separate one material from another by exploiting the difference in electrical conductivity.

High Tension roll separator was tested using a titanium roll set at 53rpm

Feed Hopper

Ionising electrode

Static electrode

Brush

Earthed titanium roll

Vibratory feeder

Insulators ConductorsMiddling

Microwave Leaching of PGM sources

Road Dust

In the UK Local Authorities collect road dust They store it at regional depots It is then sent for expensive landfill

Road Dust in UK

•Valueless Material

•Disposal costs associated with it

•Research has shown PGM levels in road dust of 1.8 parts per million (ppm)

•Primary PGMs mined in South Africa at 4-10 ppm from deep underground

•PGMs also mined in Canada at less than 1ppm

•Therefore Road Dust levels comparable to primary low grade ores

PGMs in Road Dust

2 spin out companies

◦ Biowaste2energy Ltd◦ Bioenergy from organic wastes

◦ Roads2Riches Ltd◦ Precious metal recovery from wastes

www.bw2e.com

Electrical Load

Anode

Cathode

Proton exchange membrane

H2

2 H2 → 4 H+ + 4 e-

O2 + 4 e- + 4 H+ → 2 H2O

H+

O2

Pt catalyst

e- flow

Pt catalyst

2 Requirements: PGM nano-catalyst and clean hydrogen

Aim: Bio-based fuel cell using biohydrogen and bio-recovered Pt

Fuel cell catalyst Power output (Pmax, mW)

H2

Bacteria

Organicwaste

Pre-treatment

Bioenergyreactors

CleanEnergyPEM-FC

Metalwaste

CatalystMetallised cells

Sorption &reduction

Chemicalindustry

43

1. Grow Serratia biofilm (3L bubble column reactor)2. Supply biofilm with G2P and Uranium3. Phosphatase forms Hydrogen Uranyl Phosphate (HUP)

(Alternatively Zirconium phosphate)

4. Result: “Primed” biofilm, ready to adsorb radioactive metals – e.g. Strontium, Cobalt, Caesium

Sodium glycerol 2-phosphate (G2P)

Periplasmic phosphatase

Phosphatase within extracellular polymeric substance

HPO42-

Bacterial cell

UO22+

HUO2PO4.nH2O (HUP)

2 cm

Reactor volume: ~8 mL

5 cm

Polyurethane foam coated with primed biofilm

Cleaned outflow solution

Contaminated

inflow solution

Examples of inflow radioactive metals:60Co, 85Sr and 137Cs

15ml column volume

Tests performed at the Korea Atomic Energy Research Institute (KAERI).

Removal of 60Co, 85Sr and 137Cs from simulated radioactive waste solution by ion exchange using reactors containing HUP supported on biofilm

Simulated radioactive waste: 137Cs, 85Sr and 60Co (0.333 mM), pH 5.44, flow rate 10 mL/hBreakthrough capacity: 137Cs = 0.11 mmol, 85Sr = 0.055 mmol, 60Co = 0.055 mmol Efficiency: 97%

3 integrated processes3 inter-related themes

Organicwaste

Pre-treatment

Sugarfeed

Bio-process

H2

EnergyPEM-FCMetalwaste

Bacterialcells

CatalystPd/Pt coated cells

Uranylnitrate

Sorption &reduction

Ion exchangerHUP-coated cells

Sorption & reduction

Decontamination of nuclear waste

Mol of

H2 e

quiv

ale

nt 1.5

1

0.5

2