High value, low volume, challenging to find market. Polymer. Biofuel

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1 High value, low volume, challenging to find market Food, pharmaceutical Composite Polymer Chemical and hydrogen Biofuel Low value, high volume, easy to find market Gas and CHP Fig. 1 Biorefinery products and their market drivers [1]. (Reproduced with permission from Sadhukhan et al. (2014) [1] Copyright 2014 Society of Chemical Industry and John Wiley & Sons, Ltd.)

2 Fig. 2 Microbial fuel cell (MFC) generates electricity by electron harvesting from waste streams using bacteria; protons transfer from the anode to cathode and reduce oxygen to produce water; the overall operation is exogenic. Microbial electrolysis cell (MEC) generates hydrogen using the same principle, except hydrogen production in the cathode chamber and the overall operation is endogenic needing external voltage.

3 Anode chamber: Bioelectrochemical oxidation Cathode chamber: Catalytic electro- hydrogenation, hydrodeoxygenation and reduction reactions External voltage applied Gaseous products (e.g. hydrogen, methane) e - e - H 2 and CO 2 / carbonic acid / pyruvate / formate / fatty acids Anode substrate: Organic waste/ wastewaters / C6, C5 sugars from lignocellulose / hydrolysate from lignocellulose /stillage from biodiesel and bioethanol plants / glycerol from biodiesel plant H + H + PROTON EXCHANGE MEMBRANE Proton exchange membrane (optional) CO 2 reuse in reactions Biofuel or Chemical or Polymer Cathode substrate: Wastewaters / pyruvate / organic acids e.g. α-keto acids (e.g. pyruvate - ), α,βunsaturated acids and hydroxy acids, glucose, etc. sourced from lignocellulosic wastes Fig. 3 MEC schematic with anode and cathode substrates that can be sourced from waste biomass.

4 Wood adhesives, epoxy resins, fuel additives, benzene-toluene-xylene, binders, carbon fiber Poly-urethanes, polyolefins and specialty phenolics for high value applications, such as pharmaceuticals and fragrances (vanillin) Processes: Enzymatic conversion Catalytic conversion Catalytic pyrolysis Electrocatalytic conversion 1. β-aryl ether cleavage 3. Enol ether formation Fermentation products: Ethanol, lactic acid, acetone-butanol-ethanol INORGANICS, <1% EXTRACTIVES, 3% 2. α-aryl ether cleavage 4. C-C bond cleavage Glucose polymer Endo-cellulose Amorphous regions of the chain produces oligosaccharides Exo-cellulose Chain ends produce cellobiose β-glucosidase Oligosaccharides and cellobiose produce glucose CELLULOSE, 38%-54% LIGNIN, 15%-25% HEMICELLULOSE, 24%-36% C5: Xylose enzymatic hydrolysis Chemical conversion products: Furfural, hydroxymethyl, levulinic acid, Xylite, furfural, 5-hydroxymethylfurfural, L-arabinose, furan resins and nylons Processes: Alkaline extraction Alkaline peroxide extraction Hot water / steam extraction Chemical conversion Fig. 4 Biorefinery preprocessing and processing technologies, mechanisms and products [1]. (Reproduced with permission from Sadhukhan et al. (2014) [1] Copyright 2014 Society of Chemical Industry and John Wiley & Sons, Ltd.)

5 Lignocellulose (e.g. straw, wood, etc.) Size reduction Steam pretreatment Enzyme production 1 2 Yeast propagation 1 (solid state) Fermentation Distillation, dehydration Ethanol Fractionation e.g. modified pulping / organosolv, acid hydrolysis, etc. Lignin platform Solid Solid / liquid separation of stillage Combustion C6, C5 platform Energy Liquid e - e - Electricity generated in MFC Or Voltage applied in MEC CO 2 / Acetate / H 2 H + Bioanode: Glu CO 2 / Acetate + 24H e - Air cathode in MFC: Water Or, Anaerobic cathode in MEC: Hydrogen Or, Anaerobic cathode in MEC: Hydrogen Or, Or, Anaerobic Anaerobic biocathode biocathode in in MEC: MES: Biofuel Biofuel (glutamate, (glutamate, propionate, propionate, butanol) butanol, etc.) MES Fig. 5 Integrated bioethanol and MES process flowsheet: route 1: fermentation; route 2: lignocellulose fractionation.

6 Oily residues 104 Sulphuric acid and methanol Dilute acid esterification Methanol Transesterification 1 Waste oil Glycerol refining Biodiesel refining Glycerol 10.7 (97.8% glycerol) Ethanol 5.4 Biodiesel100 (99.9% biodiesel) Stillage 5.3 (19% biodiesel) e - e - H + Bioanode: Glycerol Ethanol + CO 2 + 2H + + 2e - Electricity generated in MFC Or Voltage applied in MEC Biofuel: 6.63 Air Or, cathode Anaerobic in cathode MFC: Water in MEC: Hydrogen Or, Or, Anaerobic biocathode in MEC: in MES: Hydrogen Biofuel or Chemical Or, Anaerobic biocathode in MEC: Biofuel or Chemical Substrate for biocathode shown in Figure 1 MES Fig. 6 Process flow schematic for utilising glycerol and stillage streams of an existing biodiesel plant producing biodiesel from oily residues esterification and waste oils transesterification, in a BES. The numbers in bold are the mass units of the various flows in the integrated flowsheet, which gives biodiesel, ethanol and biofuel (biobutanol, acetate and formate) products of 100, 5.4 and 6.63 mass units, respectively. Please refer to the Supplementary material on biodiesel process flowsheet synthesis and hypothesis for MES creation for the illustration.

7 HYDROLYSED SUGARS WASTE STREAMS ORGANIC WASTE Fermentation BIOMETHANE Anaerobic digestion RECYCLE BES EFFLUENT BES NH 3 + H 2 MF / UF / NF / RO and RED / MFC BIOETHANOL BIOMETHANE CARBOXYLATE / ALCOHOLS / AMINE / AMMONIA PURE WATER FERTILIZER COMPOST Fig. 7 Integrated AD, fermentation and membrane electrolysis process (BES: bioelectrochemical synthesis) flowsheet. BES is used to remove ammonia from AD effluent, which is then recycled back to AD to increase biomethane concentration >90 vol%. Effluents from BES and AD can also be processed through MF / UF / NF, and RO for enhance recovery of nutrients and pure water. RED and MFC are used to recover some of the energies. Generated hydrogen in BES has two options: 1) React with ammonia to produce amine; 2) React with CO2 from fermentation or other processes to produce carboxylate / alcohol. Techno-economics of the integrated systems will be a subject of consideration for further research.

8 100 Ratio of current density and the exchange current density Current density in A per sq. m Activation overpotential (mv) (a) 100 Ratio of current density and the exchange current density Current density in A per sq. m Activation overpotential (mv) (b) Fig. 8 log 10 (i) (while i is in A m -2 ) with respect to activation overpotential (in mv) for two exchange current densities. (a) Exchange current density = 3.33 A m -2 ; (b) Exchange current density = 1.67 A m -2.

9 Current density (A m -2 ) 10 Limiting current density = 13.6 A per sq. m Limiting current density = 100 A per sq. m Concentration overpotential (mv) Fig. 9 log 10 (i) (while i is in A m -2 ) with respect to concentration overpotential (in mv) for two limiting current densities.

10 Potential (V) Power density (W m -3 ) Model: 0.15 Experimental: 0.15 Model: 0.50 Experimental: 0.50 Model: 1.00 Experimental: Current density (A m -2 ) (a) Model: 0.15 Experimental: 0.15 Model: 0.50 Experimental: 0.50 Model: 1.00 Experimental: Current density (A m -2 ) (b) Fig. 10 (a) Power density and (b) electrode potential as function of current density at different substrate concentrations. Numbers are the concentrations of acetate in g l -1.

11 Effective specific surface area (m 2 m -3 ) Acetate concentration (g l -1 ) Fig. 11 Availability of the cathode surface area with the progress of reaction (mean value shown by the arrowhead) for different acetate concentrations.

12 Societal needs and market demands for products Availability of waste resources and infrastructures Health, environment and job creation Policy incentives Economics Project definition: Characterise waste substrates and identify pathways to products Identify appropriate gut communities responsible for rapid rates of microbial bioconversion in nature Hypothesise metabolic pathways; Metabolic flux analysis for targeting products thermodynamic optimisation Design options and regions for operability Process Integration and flowsheet synthesis, industrial symbiosis Process simulation and dynamics Control experimentation Economics and sustainability Piloting, demonstration and fully operational symbiotically integrated process plant Fig. 12 Strategy for bioproduct and bioprocess development from ideas to market: Utilisation of predictive power.

13 Polysaccharides Starch polymers Cellulose polymers Other natural polymeric materials Natural fibres Lignin composites Polylactic acid (PLA) Poly (trimethylene terephthalate) (PTT) Polyesters Polyhydroxyalkanoates (PHAs) Other polyesters Poly (butylene terephthalate) (PBT) Poly (butylene succinate) (PBS) Poly (butylene succinate adipate) (PBSA) Polyurethanes Polyethylene furanoate (PEF) Polyurethanes (PURs) Poly (butylene succinate terephthalate) (PBST) Poly (butylene adipate terephthalate) (PBAT) Poly (ethylene terephthalate) (PET) Polyamide 6 Polyamide 6,6 Polyamides Polyamide 6,9 Polyamide 11 Polyamide 6,10 Polycarbonates Diphenolic acid polycarbonates Poly(propylene carbonate) (PPC) Fig. 13 Target polymers from integrated biorefineries [1]. (Reproduced with permission from Sadhukhan et al. (2014) [1] Copyright 2014 Society of Chemical Industry and John Wiley & Sons, Ltd.)