We are optimizing the chemical properties of soluble Mo-polypyridine electrocata­lysts for water-to-hydrogen conversion to increase turnover frequency and stability in microbial growth media. We are also seeking improvements to minimize electro­chemical overpotential for H2 production. In particular, we are targeting the incor­poration of electron-withdrawing groups at the axial and equatorial pyridine donors as well as methine bridges. Additionally, we are developing synthetic routes to more potential ligand frameworks where all the pyridines can be differentially functional­ized. The overall goal is to move the reduction potentials of these complexes to more positive values, which may lead to a decrease in the overpotential for catalytic reduction of water to hydrogen. We are also testing conditions and electrode materi­als that will allow R. eutropha to grow autotrophically with H2 generated in situ from electricity by the MoPy5 electrocatalyst.

As mentioned in the Introduction, we are pursuing two strategies to use these catalysts to generate H2 electrochemically for autotrophic growth and biofuel pro­duction. These strategies involved tethering the electrocatalyst to the electrode sur­face and to the surface of R. eutropha by expressing heterologous proteins on the surface that will bind metal complexes (Fig. 5). These two strategies will be evalu­ated in comparison to standard methods for electrolysis of H2O to generate H2 and O2 for R. eutropha growth.

Acknowledgments This work is funded by the ARPA-E Electrofuels program. We would also like to thank the Joint BioEnergy Institute (JBEI) for the use of its facilities and equipment; JBEI is supported by the Office of Science, Office of Biological and Environmental Research, of the U. S. Department of Energy. Work at Lawrence Berkeley National Laboratory is performed under the auspices of the U. S. Department of Energy through contract DE-AC02-05CH11231.

[1] The interest to be paid on these loans was lower than the rate of inflation which resulted in a nega­tive real interest rate.

[2] Theoretically one can produce 0.684 L of ethanol with 1 kg of sugar which is fairly close to the value established by the decree 76,593.

[3] Enzyme inactivation can result from a variety of irreversible processes, such as nonspecific adsorption to substrate, aggregation related to unfolding, and covalent chemical modification. These irreversible processes are favored by the relatively harsh conditions (high temperature and/ or acidic or alkaline pH) used for pretreatments that increase digestibility.

[4] This is particularly notable given that most GH families in Table 1 include numerous enzymes with noncellulolytic activities.

[5] Since modification is likely to be somewhat random, the odds of getting a block of i unmodified sugars in a row is nonzero, but it is likely to be quite small. Assuming each of the three hydroxyls per anhydroglucose are equally reactive and that their reaction does not influence reactivity of proximal hydroxyl groups, the probability is (1 — 0.7/3)3i = 0.673i. For i = 3, this is 0.09, and drops by a factor of 0.45 for every additional unmodified anhydroglucose.

[6]Endocellulase activity should strongly decrease the viscosity of CMC solutions by greatly decreasing chain length, whereas exocellulase activity should have little effect on viscosity.

[7] enzymes

[8]LD is lethal dose. The LD50 is the dose that kills half (50%) of the animals tested. The animals are usually rats or mice, although rabbits, guinea pigs, hamsters, and so on are sometimes used.

[9] Primary energy consumption comprises commercially traded fuels only, and excluding fuels such as wood, peat, animal waste, geothermal, wind and solar power generation.

T. M. Mata (*) • C. A.V. Costa

Laboratory for Process, Environmental and Energy Engineering (LEPAE),

Faculty of Engineering, University of Porto (FEUP), R. Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal e-mail: tmata@fe. up. pt

A. A. Martins

Center for Transport Phenomena Studies (CEFT) , Faculty of Engineering,

University of Porto (FEUP) , R. Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal

[11] K. Sikdar

National Risk Management Research Laboratory, Office of Research and Development,

U. S. Environmental Protection Agency, 26 West Martin Luther King Drive,

Cincinnati, OH 45268, USA

N. S. Caetano

Laboratory for Process, Environmental and Energy Engineering (LEPAE),

Faculty of Engineering, University of Porto (FEUP), R. Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal

Department of Chemical Engineering, School of Engineering (ISEP),

Polytechnic Institute of Porto (IPP), R. Dr. Antonio Bernardino de Almeida, s/n, 4200-072 Porto, Portugal

J. W. Lee (ed.), Advanced Biofuels and Bioproducts, DOI 10.1007/978-1-4614-3348-4_31, 745

© Springer Science+Business Media New York 2013

G. J. Moridis (H) • J. Rutqvist • T. Kneafsey • M. T. Reagan • M. Kowalsky Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA e-mail: GJMoridis@lbl. gov

T. S. Collett

U. S. Geological Survey, Denver, CO 80225, USA

R. Boswell

National Energy Technology Laboratory, Morgantown, WV 26507, USA

[13] Hancock

RPS Energy, Calgary, AB, Canada T2P 3T6 C. Santamarina

Georgia Institute of Technology, Atlanta 30332, GA M. Pooladi-Darvish

University of Calgary, Calgary, Canada T2N 1N4 E. D. Sloan • C. Coh

Colorado School of Mines, Golden, CO 80401, USA

J. W. Lee (ed.), Advanced Biofuels and Bioproducts, DOI 10.1007/978-1-4614-3348-4_37, 977

© Springer Science+Business Media New York 2013

[14] The NASA estimate, based on a Congressional Budget Office report, A Budgetary Analysis of NASA’s New Vision for Space, found the Apollo program cost in 2005 dollars to be approximately $170 billion. The estimate includes costs for research and development; procurement of rockets, command and lunar modules; management; facilities, including construction and upgrading; and flight operations.