A Green Plastic Formed Directly from Carbon Dioxide and Sunlight Jian Yu School of Ocean & Earth Science & Technology University of Hawaii at Manoa Hawaii, USA Presented at Biopolymers & Bioplastics 2015 San Francisco www.hnei.hawaii.edu

Conventional bioplastics from biomass Land farming to produce renewable feedstock Producing bioplastics from starch, sugar and oil Low energy efficiency of plants (<1% solar radiation ) http://www.hnei.hawaii.edu

Photosynthetic CO2 fixation in plant cell CO2 + H2O + hv  CH2O + O2 Our conclusions: Light capture and CO2 fixation should be decoupled The light capture is replaced by artificial device for more efficient use of solar energy http://www.hnei.hawaii.edu

Artificial photosynthetic system CO2 + H2O + hv  CH2O (biopolymers) http://www.hnei.hawaii.edu

H2 from Intermittent solar energy Anode: 2H2O (l)  O2 (g) + 4H+(aq) + 4e Cathode: 4H+(aq) + 4e  2H2 (g) Overall: 2H2O(l)  O2(g) + 2H2 (g) http://www.hnei.hawaii.edu

CO2 fixation by a chemautotrophic bacterium http://www.hnei.hawaii.edu

Conventional versus novel bioreactor Conventional BR Novel BR Cell density (g/L) 24 27 PHB (wt%) 59 52 Cell productivity (g/L.hr) 0.23 0.42 PHB yield (g/g H2) 0.1 0.38 http://www.hnei.hawaii.edu

A Bioplastic of 100% CO2 carbon Fate of residual biomass? http://www.hnei.hawaii.edu

Residual biomass as nutrients in CO2 fixation After PHB recovery, the residual cell mass becomes N-rich hydrolysates. http://www.hnei.hawaii.edu

Life cycle analysis (LCA) Cradle to gate Gate to grave CO2, H2O Biodegradation for clean environment Solid waste disposal via incineration (heat), composting (soil) CO2 H2O Sunlight Minerals NH3 Question: Can PHB bioplastic be reused for more value? http://www.hnei.hawaii.edu

Bio-based chemicals from PHB platform http://www.hnei.hawaii.edu

PHB Thermal Degradation & Reaction Mechanism http://www.hnei.hawaii.edu

Aromatics from PHB S Kang, J Yu. RSC Advances 2015, 5, 3005-30013. C3H6 S Kang, J Yu. RSC Advances 2015, 5, 3005-30013. http://www.hnei.hawaii.edu

Alkenes from PHB Catalyst O-containing Chemicals (%)* Alkenes (%)* Benzenes Naphthalenes A 19.6 2.6 65.8 11.2 B 9.9 57.0 31.1 2.0 *Based on percentage of peak areas in GCMS chromatograms http://www.hnei.hawaii.edu

Gasoline-grade Biofuel from PHB Fuels Gasolinea Light-oil Heavy-oil Biodiesel b BP (oC) 40-240 240-310 182-338 C (wt%) 80.40 81.37 79.38 76.96 H (wt%) 12.30 11.30 9.67 11.85 N (wt%) 0.15 0.14 0.23 - O (wt%)c 6.35 7.19 10.72 9.41 HHV (MJ/kg) 41.8 41.4 38.4 39.7 a Commercial gasoline with ethanol, light-oil and heavy-oil analyzed by Hazen Research Inc b Properties of biodiesel from references c Roundup to 100 wt% http://www.hnei.hawaii.edu

Closing remark: reducing the cost http://www.hnei.hawaii.edu

Thank You !!! Acknowledgement Students and post-doctors Office of Naval Research for financial support Thank You !!! http://www.hnei.hawaii.edu