1. 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

2. 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 )

3. 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

4. Artificial photosynthetic system
CO2 + H2O + hv  CH2O (biopolymers)

5. 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)

6. CO2 fixation by a chemautotrophic bacterium

7. 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

8. A Bioplastic of 100% CO2 carbon
Fate of residual biomass?

9. Residual biomass as nutrients in CO2 fixation
After PHB recovery, the residual cell mass becomes N-rich hydrolysates.

10. 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?

11. Bio-based chemicals from PHB platform

12. PHB Thermal Degradation & Reaction Mechanism

13. Aromatics from PHB S Kang, J Yu. RSC Advances 2015, 5, 3005-30013.
C3H6
S Kang, J Yu. RSC Advances 2015, 5,

14. 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

15. Gasoline-grade Biofuel from PHB
Fuels
Gasolinea
Light-oil
Heavy-oil
Biodiesel b
BP (oC)
40-240
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%

16. Closing remark: reducing the cost

17. Thank You !!! Acknowledgement Students and post-doctors
Office of Naval Research for financial support
Thank You !!!