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Title: Printable enzyme-embedded materials for methane to methanol conversion

Abstract

An industrial process for the selective activation of methane under mild conditions would be highly valuable for controlling emissions to the environment and for utilizing vast new sources of natural gas. The only selective catalysts for methane activation and conversion to methanol under mild conditions are methane monooxygenases (MMOs) found in methanotrophic bacteria; however, these enzymes are not amenable to standard enzyme immobilization approaches. Using particulate methane monooxygenase (pMMO), we create a biocatalytic polymer material that converts methane to methanol. We demonstrate embedding the material within a silicone lattice to create mechanically robust, gas-permeable membranes, and direct printing of micron-scale structures with controlled geometry. Remarkably, the enzymes retain up to 100% activity in the polymer construct. The printed enzyme-embedded polymer motif is highly flexible for future development and should be useful in a wide range of applications, especially those involving gas–liquid reactions.

Authors:
 [1];  [1];  [1];  [1];  [1];  [1];  [1];  [2];  [2];  [1]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. Northwestern Univ., Evanston, IL (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1349013
Report Number(s):
LLNL-JRNL-678269
Journal ID: ISSN 2041-1723
Grant/Contract Number:
AC52-07NA27344
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 7; Journal ID: ISSN 2041-1723
Publisher:
Nature Publishing Group
Country of Publication:
United States
Language:
English
Subject:
03 NATURAL GAS; 59 BASIC BIOLOGICAL SCIENCES

Citation Formats

Blanchette, Craig D., Knipe, Jennifer M., Stolaroff, Joshuah K., DeOtte, Joshua R., Oakdale, James S., Maiti, Amitesh, Lenhardt, Jeremy M., Sirajuddin, Sarah, Rosenzweig, Amy C., and Baker, Sarah E. Printable enzyme-embedded materials for methane to methanol conversion. United States: N. p., 2016. Web. doi:10.1038/ncomms11900.
Blanchette, Craig D., Knipe, Jennifer M., Stolaroff, Joshuah K., DeOtte, Joshua R., Oakdale, James S., Maiti, Amitesh, Lenhardt, Jeremy M., Sirajuddin, Sarah, Rosenzweig, Amy C., & Baker, Sarah E. Printable enzyme-embedded materials for methane to methanol conversion. United States. doi:10.1038/ncomms11900.
Blanchette, Craig D., Knipe, Jennifer M., Stolaroff, Joshuah K., DeOtte, Joshua R., Oakdale, James S., Maiti, Amitesh, Lenhardt, Jeremy M., Sirajuddin, Sarah, Rosenzweig, Amy C., and Baker, Sarah E. 2016. "Printable enzyme-embedded materials for methane to methanol conversion". United States. doi:10.1038/ncomms11900. https://www.osti.gov/servlets/purl/1349013.
@article{osti_1349013,
title = {Printable enzyme-embedded materials for methane to methanol conversion},
author = {Blanchette, Craig D. and Knipe, Jennifer M. and Stolaroff, Joshuah K. and DeOtte, Joshua R. and Oakdale, James S. and Maiti, Amitesh and Lenhardt, Jeremy M. and Sirajuddin, Sarah and Rosenzweig, Amy C. and Baker, Sarah E.},
abstractNote = {An industrial process for the selective activation of methane under mild conditions would be highly valuable for controlling emissions to the environment and for utilizing vast new sources of natural gas. The only selective catalysts for methane activation and conversion to methanol under mild conditions are methane monooxygenases (MMOs) found in methanotrophic bacteria; however, these enzymes are not amenable to standard enzyme immobilization approaches. Using particulate methane monooxygenase (pMMO), we create a biocatalytic polymer material that converts methane to methanol. We demonstrate embedding the material within a silicone lattice to create mechanically robust, gas-permeable membranes, and direct printing of micron-scale structures with controlled geometry. Remarkably, the enzymes retain up to 100% activity in the polymer construct. The printed enzyme-embedded polymer motif is highly flexible for future development and should be useful in a wide range of applications, especially those involving gas–liquid reactions.},
doi = {10.1038/ncomms11900},
journal = {Nature Communications},
number = ,
volume = 7,
place = {United States},
year = 2016,
month = 6
}

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Cited by: 3works
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  • The authors purpose in this Account is to review the structural work on the hydroxylase carried out in the context of the now known X-ray structure. The authors address the question, How well did the noncrystallographic methods reveal key features of the protein structure? Of particular interest were the following questions: (1) What is the structure of the holoenzyme, and how do the three subunits interact: (2) How many diiron centers are present, and which subunit(s) accomodates(s) them? (3) What exogeneous and endogeneous species are coordinated to the diiron center, and what specific amino acid residues serve as ligands? (4)more » How does the hydroxylase interact with the other two MMO proteins? Discussion begins with spectroscopic and biochemical data obtained with methodologies other than X-ray crystallography and the resulting models pertaining to each of the foregoing structural questions. The authors then briefly discuss the X-ray determination and conclude by comparing the known structure to the models derived from the noncrystallographic experiments. 60 refs., 6 figs.« less
  • Solution-based printable transparent conducting electrodes consisting of Ag nanowire (NW) and indium tin oxide (ITO) nanoparticles (NPs) were fabricated by simple brush painting at room temperature under atmospheric ambient conditions. Effectively embedding the Ag NW percolating network into the ITO NPs provided a conduction path, led to a metallic conduction behavior of the ITO NPs/Ag NW/ITO NPs multilayer and supplied electrons into the ITO NPs. The optimized ITO NPs/Ag NW/ITO NPs multilayer showed a sheet resistance of 16.57 Ω/sq and an optical transparency of 79.50% without post annealing. Based on high resolution transmission electron microscope analysis, we investigated the microstructure andmore » interface structure of the ITO NPs/Ag NW/ITO NPs multilayer electrodes and suggested a possible mechanism to explain the low resistivity of the multilayers.« less
  • The selective oxidation of methane to methanol or other efficiently transportable material represents one of the outstanding challenges of the chemical industry. Methane, being the dominant component of natural gas, is an abundant resource, yet in comparison with petroleum products it is currently underutilized, mainly because the transportation of a gas with a very low boiling point is expensive. The situation could change drastically if a simple, efficient, and economical method were found to convert methane to a readily transportable material such as methanol. The recent announcement by Periana et al. (Science, 1998, 280, 560) of 70% one-pass homogeneous catalysismore » of methane-to-methanol conversion with high selectivity in sulfuric acid solution under moderate conditions represents an important advance in the selective oxidation of alkanes, an area of considerable current interest and activity. The conversion is catalyzed by bis(2,2{prime}-bipyrimidine)Pt(II)Cl{sub 2}. In this work, the thermodynamics of the activation and functionalization steps of the related cis-platin-catalyzed process in H{sub 2}SO{sub 4} are calculated using density functional techniques, including the calculation of solvation free energies by a dielectric continuum method. It is concluded that electrophilic attack by CH{sub 4} on an intermediate which may be regarded as a tetracoordinate solvated analogue of a gas-phase, T-shaped, three-coordinate Pt(II) species, followed by oxidation of the resulting methyl complex to a methyl bisulfate ester, is thermodynamically feasible. This is in general accord with the mechanism proposed by Periana et al., but now, on the basis of the computational predictions, the nature of the active catalyst, as well as that of the intermediates, can be more precisely defined. While the alternative mechanism of oxidative addition does not appear to be thermodynamically feasible when using Pt(II) catalysts, catalysis by a Pt(IV) species is predicted to be, on thermodynamic grounds, a viable alternative pathway.« less
  • The hybrid density functional (DFT) method B3LYP was used to study the mechanism of the methane hydroxylation reaction catalyzed by a non-heme diiron enzyme, methane monooxygenase (MMO). The key reactive compound Q of MMO was modeled by (NH{sub 2})(H{sub 2})Fe({micro}-O){sub 2}({eta}{sup 2}-HCOO){sub 2}Fe(NH{sub 2})(H{sub 2}O), (1). The reaction is shown to take place via a bound-radical mechanism and an intricate change of the electronic structure of the Fe core is associated with the reaction process. Starting with (1), which has a diamond-core structure with two Fe{sup IV} atoms, L{sub 4}Fe{sup IV}({micro}-O){sub 2}Fe{sup IV}L{sub 4}, the reaction with methane goes overmore » the rate-determining H-abstraction transition state to reach a bound-radical intermediate, L{sub 4}Fe{sup IV}({micro}-O)({micro}-OH({center{underscore}dot}{center{underscore}dot}{center{underscore}dot}CH{sub 2}))Fe{sup III}L{sub 4}, which has a bridged hydroxyl ligand interacting weakly with a methyl radical and is in an Fe{sup III}-Fe{sup IV} mixed valence state. This short-lived intermediate easily rearranges intramolecularly through a low barrier at transition state for addition of the methyl radical to the hydroxyl ligand to give the methanol complex, L{sub 4}Fe{sup III}(OHCH{sub 3})({micro}-O)Fe{sup III}L{sub 4}, which has an Fe{sup III}-Fe{sup III} core. The barrier of the rate-determining step, methane H-abstraction, was calculated to be 19 kcal/mol. The overall CH{sub 4} oxidation reaction to form the methanol complex, (1) + CH{sub 4}{r{underscore}arrow} L{sub 4}Fe{sup III}(OHCH{sub 3})-({micro}-O)Fe{sup III}L{sub 4}, was found to be exothermic by 39 kcal/mol.« less
  • The C-H activation of methane catalyzed by cis- and trans-platin in aqueous solution has been studied by density functional based computational methods. By analogy with the Shilov reaction, the initial step is the replacement of an ammonia ligand by methane, followed by the formation of a methyl complex and the elimination o a proton. The computations utilize the B3LYP hybrid functionals, effective core potentials, and double-{zeta} to polarized double-{zeta} basis sets and include solvation effects by a dielectric continuum method. In contrast with the Shilov reaction studied by Seigbahn and Crabtree (J.Am.Chem.Soc. 1996, 118, 4443), in the platins the replacementmore » of an ammonia ligand by methane is found to be effectively rate determining, in that the energy barriers to C-H activation are comparable with those of the initial substitution reaction, viz. {approximately} 34 and 44 kcal/mol for cis- and trans-platin, respectively. Several reaction pathways for C-H activation and subsequent proton elimination were identified. For cis-platin the energy barriers associated with the oxidative addition and {sigma}-bond metathesis type mechanisms were found to be comparable, while for trans-platin oxidative addition is predicted to be strongly preferred over {sigma}-bond metathesis, which, interestingly, also proceeds through a Pt(IV) methyl hydrido complex as reaction intermediate. In line with accepted ideas on trans influence, the methyl and hydride ligands in the Pt(IV) complexes that arise in the oxidative addition reactions were always found to be cis to each other. On the basis of the population analyses on the Pt(IV) complexes it is suggested that the Pt-H and Pt-CH{sub 3} bonds are best described as covalent bonds and, further, that the preference of the hydride and methyl anions to be cis to each other is a consequence of such covalent bonding. In light of these findings, the energies of several methyl Pt(IV) hydrido bisulfate complexes were also recalculated, with CH{sub 3} and H places cis to each other. The revised results provide evidence for the thermodynamic feasibility of oxidative addition of methane to catalysts such as [Pt(NH{sub 3}){sub 2}(OSO{sub 3}H){sub 2}] or [Pt(NH{sub 3}){sub 2}(OSO{sub 3}H)(H{sub 2}SO{sub 4})]{sup +}.« less