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RESEARCH I REPORTS
<br /> limiting(-2 days),as indicated by the cessation 15. M.W.Kanan,D.G.Nocera,Science 321,1072-1075(2008). 33.J.Lu,C.J.Brigham,C.S.Gai,A.J.Sinskey,Appl.Microbiol.
<br /> of biomass accumulation(Fig.3A)as well as the 16. S.Y.Reece et al.,Science 334.645-648(2011). Biotechnol.96,283-297(2012).
<br /> measured every 24 hours(Fig.3B and fig.S13), 17. A.Pohlmann et al„Nat.Biotechnol.24,1257-1262
<br /> rlelec (2006). ACKNOWLEDGMENTS
<br /> With a titer of-700 mg/liter,the 6-day average for 18.J.P.Torella et al.,Proc.Natl.Acad.Sci.U.S.A.112,2337-2342 We thank N.Li for ICP-MS measurement and reagents,and J.Torella,
<br /> PHB synthesis was r1eec=36±3%(Fig.2A,entry 9) (2015). C.Myhrvold•C.Lemon,and M.Huynh for helpful discussions.C.L.
<br /> with a 24-hour maximum of rim=42±2%(n=3) 19. D.A.Lutterman,Y.Surendranath,D.G.Nocera,J.Am.Chem. acknowledges X.Ling at Nanyang Technological University.Supported
<br /> (Fig.3B).In engineered strains(32,33),this PHB Soc.131,3838-3839(2009), by a Lee Kuan Yew Postdoctoral Fellowship(C.L.),a predoctoral
<br /> 20.D.K.Bediako,A.M.Ullman,D.G.Nocera,Top.Curr.Chem. fellowship from the NSF Graduate Research Fellowships Program
<br /> pathway could be modified to excrete the fusel 371,173-213(2016). ofNaval Research Multidisciplinary UniversityResearch
<br /> (B.C.C.),Office p ry
<br /> alcohols isopropanol(C3),isobutanol(C4),and 21. I.Paseka,J.Velicka,Electrochim.Acta 42,237-242 Initiative award N00014-11-1-0725(P.A.S.),Air Force Office of
<br /> 3-methyl-1-butanol(C5),which possess energy den- (1997). Scientific Research grant FA9550-09-1-0689(D.G.N.).the Wyss
<br /> cities of 24, 28, and 31 MJ/liter, respectively.The 22.Y.Surendranath,D.A.Lutterman,Y.Liu,D.G.Nocera,J.Am. Institute for Biologically Inspired Engineering(P.A.S.),and the Harvard
<br /> Chem.Soc.134,6326-6336(2012). University Climate Change Solutions Fund.This work was performed
<br /> culture supernatant was then analyzed to quantify 23.See supplementary materials on Science Online. under the First 100 W Program at Harvard University.C,L.,B.C.C.,M.Z.,
<br /> the secreted alcohols (23). The accumulation 24.M.Dinca,Y.Surendranath,D.G.Nocera,Proc.Natl.Acad.Sci. P.A.S.,and D.G.N.are inventors on patent applications(62/218,131)
<br /> of these liquid fuels followed trends similar to U.S.A.107,10337-10341(2010). filed by Harvard University and Harvard Medical School related
<br /> those observed for PHB synthesis.As shown in Fig. 25.J.Yu,A.Dow,S.Pingali,Int.J.Hydrogen Energy 38, to the technology described in this paper.The genome sequences
<br /> 8683-8690(2013). are accessible in the NCB!SRA database under accession
<br /> 3,C and E,biomass production reached a plateau 26.G.T.Rochelle,Science 325,1652-1654(2009). number SRP073266.
<br /> while isopropanol titers grew to -600 mg/liter 27.J.R.Roede,G.W.Miller,in Encyclopedia of Toxicology,
<br /> and C4+C5 alcohol titers grew to-220 mg/liter. P.Wexler,Ed.(Academic Press,ed.3,1984),pp.756-758.
<br /> R.eutropha 28.M.Ludwig,J.A.Cracknell,K.A.Vincent,F.A.Armstrong, SUPPLEMENTARY MATERIALS
<br /> An engineered trophy strain produced iso- 0.Lenz,J.Biol.Chem.284,465-477(2009). www.sciencemag.org/content/352/6290/1210/suppl/DC1
<br /> propanol with a 6-day average Tlelec= 31 ±4% 29.A.M.Appel et al.,Chem.Rev.113,6621-6658(2013). Methods
<br /> (Fig.2A, entry 10)and a 24-hour maximum of 30.A.Parkin.J.Seravalli,K.A.Vincent,S.W.Ragsdale, Tables S1 to S3 0
<br /> rlelec=39±2%(n=4)(Fig.3D);a strain engi- F.A.Armstrong,J.Am.Chem.Soc.129,10328-10329(2007). Figs.S1 to S14 N
<br /> 31.T.Reda,C.M.Plugge,N.J.Abram,J.Hirst,Proc.Natl.Acad. References(34-49)
<br /> neered to produce C4+C5 alcohols averaged a Sci.U.S.A.105.10654-10658(2008). a)
<br /> 6-day llelec=16±2%(Fig.2A,entry 11)with a 32.E.Grousseau,J.Lu,N.Gorret,S.E.Guillouet,A.J.Sinskey, 18 February 2016;accepted 22 April 2016 0
<br /> 24-hour maximum of rielee = 27± 4% (n = 3) Appl.Microbiol.Biotechnol.98,4277-4290(2014). 10.1126/science.aaf5039
<br /> (Fig. 3F). The achieved titers are higher than
<br /> previous reported values,and rleiec values have o
<br /> increased by a factor of at least 20 to 50(10,18).
<br /> ai
<br /> R.eutropha has demonstrated tolerance toward ECOTOXICOLOGY et
<br /> isopropanol(fig.S14),allowing for enriched prod
<br /> uct concentrations under extended operation.
<br /> Environmentallyrelevant
<br /> Our combined catalyst design mitigates bio-
<br /> ...
<br /> toxicity at a systems level, allowing water- • , ti
<br /> splitting catalysis to be interfaced with engineered concentrations of microplastic
<br /> organisms to realize high CO2 reduction efficien-
<br /> cies that exceed natural photosynthetic systems. influence larval fish ecology
<br /> Because Et required for water splitting is low particleski
<br /> (1.8 to 2.0 V),high rleiec values are achieved that ,
<br /> translate directly to high solar-to-chemical efficien- Oona.M.Lonnstedt*and Peter Elam
<br /> E
<br /> des (ism) when coupled to a typical solar-to-
<br /> electricity device (riscE = rlsolar x rlelec)• For a The widespread occurrence and accumulation of plastic waste in the environment have cs
<br /> photovoltaic device of nsoiar=18%,the Co-PICoPIlbecome a growing global concern over the past decade.Although some marine organisms ce
<br /> .1?. eutropha hybrid system can achieve 11SCE = have been shown to ingest plastic,few studies have investigated the ecological effects 0
<br /> 9.7%for biomass,7.6%for bioplastic,and 7.1% of plastic waste on animals. Here we show that exposure to environmentally relevant 3
<br /> for fusel alcohols.This approach allows for the concentrations of microplastic polystyrene particles(90 micrometers)inhibits hatching, o
<br /> �
<br /> development of artificial photosynthesis with decreases growth rates,and alters feeding preferences and innate behaviors of European
<br /> efficiencies well beyond that of natural photo- perch(Perca fluviatilis)larvae.Furthermore,individuals exposed to microplastics do not
<br /> synthesis,thus providing a platform for the dis- respond to olfactory threat cues,which greatly increases predator-induced mortality rates.
<br /> tributed solar production of chemicals. Our results demonstrate that microplastic particles operate both chemically and physically
<br /> REFERENCES AND NOTES on larval fish performance and development.
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