Nano biofuel production processes: using nantechnology to enhance production fo biofuels
09828580 · 2017-11-28
Assignee
Inventors
Cpc classification
B82Y5/00
PERFORMING OPERATIONS; TRANSPORTING
Y02E50/10
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
C12M43/02
CHEMISTRY; METALLURGY
B82Y30/00
PERFORMING OPERATIONS; TRANSPORTING
International classification
Abstract
Methods, systems, devices and materials for producing biofuels under nanoscale control (“nanobiofuels”) are provided. In one aspect, the invention provides method for producing a biofuel, including providing a hydrocarbon producing organism; exposing the biological hydrocarbon producing organism to conditions effective to cause substantial release of the hydrocarbon from the biological hydrocarbon producing organism; and isolating at least a portion of the hydrocarbon. At least one of the actions of providing, exposing, and isolating is performed using a corresponding nanoscale control.
Claims
1. A biorefinery, comprising: a biological hydrocarbon producing organism incubator; a waste collector in fluid communication With said biological hydrocarbon producing organism incubator; a bioreaction chamber in fluid communication with said biological hydrocarbon producing organism incubator, said bioreaction chamber including nanoscale solid supports and magnetic nanoparticles and further including microbes selected from the group consisting of Ax99-59 or JH146 microbes, wherein said microbes are bound to micron-sized particles or nanobeads; and a purification chamber in fluid communication with said bioreaction chamber; wherein at least one of said incubator, bioreaction chamber, and purification chamber is under nanoscale control or includes at least one nanotechnological material.
2. The biorefinery of claim 1, wherein said nanobeads are arranged in a 2-D or 3-D-matrix.
3. The biorefinery of claim 2, wherein said matrix provides a high packing density.
4. The biorefinery of claim 3, wherein said matrix includes microfluidic or nanofluidic channels, said microfluidic or nanofluidic channels being dimensioned and configured to enable small molecules and dissolved gasses to migrate from said bioreaction chamber to said waste collector or said purification chamber.
5. The biorefinery of claim 4, wherein said bioreaction chamber includes magnetic nanoparticles configured to create turbulence in said bioreaction chamber to cause thereby mixing of reactants and products in said bioreaction chamber and separate products from waste.
6. The biorefinery of claim 1, further including a supplemental reaction zone.
Description
4 BRIEF DESCRIPTION OF THE DRAWINGS
(1) Exemplary embodiments of the present invention are described herein with reference to the following drawings, in which:
(2)
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(4)
5 DETAILED DESCRIPTION OF SOME EMBODIMENTS OF THE INVENTION
(5) 5.1 Overview
(6) The present invention provides the novel insight that nanoscale control and nanotechnological methods and materials and methods (i.e., methods based on the application of nanotechnological materials and insights of material interactions at the nanoscale) provide unique advantages over traditional methods of producing biofuels. As used herein, “nanoscale” or “nanotechnological” refers to technologies or methods that are based on the ability to probe, measure, manipulate, produce, or control systems at a scale at or below about 100 nanometer (nm). “Precision Control” as used herein refers to the ability to control systems at a scale at or below about 100 nm. As those having ordinary skill in the art will understand, interactions at nanoscale or nanotechnological distances can be markedly different from the interactions at scales greater than 100 nm. In terms of controlling processes, such as processes for producing biofuels from organisms, chemical or biochemical reactions, the ability to produce and precision control such processes at the nanoscale can bestow several unanticipated benefits and advantages than have heretofore been possible by traditional “macroscale processes” such as bulk production processes or macroscopic control and manipulation methods. Examples of such conventional macroscale processes include but are not limited to controlling pH of a solution by adding acids or bases in bulk to a mixture, filtering organisms in bulk using membrane filters. By relying on thermodynamic and bulk (macroscopic) physical principles, macroscale processes are based on large statistical averages of entire populations of chemical or biochemical species; such averages are often too coarse to enable careful precision control and optimization of the process. Thus, current methods for producing biofuels are macroscopic bulky methods and consume large amounts of energy, produce large amounts of waste product for every unit of desired product, and rely chiefly upon diffusion and Brownian motion to facilitate the largely random interactions among all of the agents, ingredients, or species present in the mixture.
(7) In sharp contrast, the processes, methods, materials, and devices provided by the present invention utilize nanoscale or nanotechnological controls to produce a finer level of precision control over biofuel production processes. Without wishing to bound to any particular theory of action, such finer control or precision control or nanoscale control and detection capabilities enables much greater precision in measurements of key control parameters as well as much greater precision and accuracy in fine-tuning these control parameters. These nanoscale methods enable a much greater sensitivity to chemical and organismal identity and outputs when processes can be controlled and influenced at nanotechnological distances, as will be described in greater detail herein below. In particular, the processes of the invention provide greater precision control, nanoscale control, and accuracy with respect to the organisms used in the production of biofuels and enable the tuning of the system to drive the selected production of a desired metabolite over unwanted products. Thus, this invention discloses nanoscale methods to genetically and metabololically fine tune organisms and downstream production processes to maximize the production of desired products and hence increase the yield of biofuel production.
(8) In conjunction with the greater degree of precision, specificity, accuracy and, ultimately, control of the various steps of the production process (either individually, wholly, or in some combination of each step and sub-process thereof), the present invention further includes the use of mathematical modeling in conjunction with the nanoscale methods and materials and processes described herein to obtain further improvements in biofuel production efficiency. As will be apparent to those having ordinary skill in the art upon reading the description of the present invention herein, the use of mathematical modeling, e.g., using network and systems theory, based on the capacity of nanotechnolgical processes to measure conditions and deliver reagents with greater precision and accuracy than available using the sorts of macroscopic controls traditionally available, will provide even greater process optimization than expected using conventional techniques. More particularly, the methods and materials provided by the present invention can reduce the cost of biofuel from algae from a current rate of about $60/bbl to less than about $10/bbl, more particularly less than about $6/bbl, and still more particularly less than about $1/bbl.
(9) 5.2 Definitions
(10) As used herein, the term “hydrocarbon” refers to any chemical compound continaing hydrogen and carbon that has utility as a biofuel or a precursor to a biofuel and that can be produced by, or derived from, a naturally occurring or genetically modified organism. The term “hydrocarbon” as used herein includes both straight-chain and branched and cyclic molecules, aliphatic and aromatic molecules (and combinations thereof), and further extends beyond compounds composed exclusively of hydrogen and carbon (e.g., methane, ethane, and propane) to include substitutions such as, but not limited to, hydroxy (OH), thio (SH), halogen (F, Cl, Br, I), carboxy (COOH), and carbonyl (═O).
(11) As used herein, the term “biofuel” refers generally to any of a wide range of liquid, solid biomass, or biogas fuels that are in some way derived from a carbon source that can be rapidly replenished, (including for example hydrocarbons derived from or produced by biological organisms), referred to herein as “biofuels” and “nanobiofuels” when using nanoscale control methods, nanotechnological materials and principles.
(12) As used herein, an “organism” is any contiguous life form or system, living or dead, especially one that at some point was capable of growth and reproduction. In particular, “organism” as used herein includes, but is not limited to, bacteria, macro-algae, and micro-algae, animal, plant, fungus, or other micro-organism.
(13) 5.3 Processes for Making Biofuels Under Nanoscale Control
(14) 5.3.1 From Algae and Microalgae
(15) In a first aspect, shown at 1000 in
(16) In some embodiments, the algae are first selected for superior production characteristics. For example, algae can be selected for superior hydrocarbon production or other favorable property, alone or in combination. In a more specific embodiment, a nanoscale detection process (for example, Gene-RADAR® from Nanobiosym Diagnostics, Inc.) is used to identify, screen, genetically engineer and select optimal organism (i.e., algae, bacterial, or other microbial) strains. In one particular embodiment, the nanoscale detection process uses one or more cell surface markers to identify the algae having desirable properties. Such cell surface markers include, but are not limited to, gene fragments, polypeptides, and antigens presented on the cell surface. In another particular embodiments, nanoscale detection process (e.g, Gene-RADAR®) are used to identify, screen, genetically engineer and select optimal genetic (i.e., DNA or RNA markers) corresponding to desirable traits that lead to the most efficient and optimum biofuel production process. The correlation of performance with the identity of the organism can be done using methods and materials known to those having ordinary skill in the art. In one specific embodiment, the GENE-RADAR® platform is used to optimize the growth conditions, lipid production, and other performance parameters of various algae and other organisms to maximize the production of biofuels therein. Still other useful methods are described in U.S. Pat. No. 7,494,791, incorporated herein in its entirety and for all purposes. Another useful device for detecting and sorting cells for use with the present invention is described in U.S. Pat. No. 7,355,696, incorporated herein by reference in its entirety and for all purposes.
(17) In other embodiments, the above-described correlation is performed as a function of the metabolic state of algae by measuring components of the metabolome of the organism. Again, those of ordinary skill in the art will be able to use the above-described techniques to perform the necessary correlations and identification.
(18) After the selection and provision of the microbes or organism, the organism is grown in a suitable environment. The growth and cultivation of such algae will be familiar to those having ordinary skill in the art, as illustrated by the above-listed incorporated U.S. patents and published patent applications. In one exemplary embodiment, the algae are grown in a bioreactor that is tunable and nanoengineered to provide nanoscale control over various control knobs or environmental parameters that influence or enhance the biofuel production process. In another embodiment, the organisms are grown in an integrated biorefinery. One exemplary biorefinery comprises an 8-acre pond that is divided to 4 smaller raceway-type ponds on the lateral axis. Each of the raceway ponds are about 2 acres and include a single paddlewheel to impart a gentle rotation to the water in the pond. The water depth is between about 12 inches and about 18 inches and is fed fresh water from wells that is slightly saline. A bloom of the provided algae is seeded into the raceway ponds using a trailer device that also delivers catfish fry into the pond. In some embodiments, only atmospheric CO.sub.2 is provided to the algae; in other embodiments additional CO.sub.2 is also provided. During warm and sunny months, the algae are harvested after between about 4 months and about 6 months.
(19) In some embodiments, magnetic nanoparticles (or sub-mircon particles) are used to create desirable, precision controlled agitation or mixing of the water and growth medium in place of, or in addition to, the above-mentioned paddlewheel. The configuration and operation of such magnetic nanoparticle-mediated agitation will be familiar to those having ordinary skill in the art, e.g., as described in “Magnetic Mixing Creates Quite A Stir”, ScienceDaily (DOE/Sandia National Laboratories (Oct. 29, 2009), Retrieved Jun. 25, 2010), and “Use of Magnetic Nanoparticles for Mixing in Microarrays and Microsystems”, Agarwal, Sandip, Ph.D. Thesis, Department of Chemical Engineering, Rice University, published on-line 3 Jun. 2009, both of which are incorporated herein by reference in their entireties and for all purposes.
(20) In some embodiments, at least one factor for cultivating the organism is determined or controlled using a nanotechnological process, nanoscale production process, or nanoscale material. In one embodiment, the present invention includes providing light at one or more frequencies chosen to optimize the growth and desired hydrocarbon production capacity of the provided algae (or other organism) using nanoscale materials and controls. Such lighting can be provided using methods and materials available to those having ordinary skill in the art (see. e.g., Ashby, et al., Nano-materials, Nanotechnologies and Design: An Introduction for Engineers and Architects (Butterworth-Heinemann 2009), which in incorporated herein by reference in its entirety and for all purposes). Other suitable exemplary nanoscale materials and methods for providing light at a desired wavelength are described in U.S. Pat. Nos. 7,235,792; 6,726,992; 7,737,632; 7,741,145; 7,728,504; 7,731,389; and 7,641,815, each of which is incorporated herein in its entirety and for all purposes. In addition, light filters using nanoscale materials can be used to provide suitable light for optimized growth; such materials are familiar to those having ordinary skill in the art as illustrated by, e.g., U.S. Pat. Nos. 7,450,306 and 7,276,685, each of which is incorporated herein in its entirety and for all purposes. In more specific embodiments, the light source is computer-controlled, and, in more particular embodiments, the light source is controlled to provide a pulsating light signal. In still more particular embodiments, the light source is a split-wavelength light source. Yet more specific embodiments include a computerized, pulsating, split-wavelength light source. Those having ordinary skill in the art can provide such light sources, e.g, as described in Gordon, J. W., and Polle, J. E. W. “Ultrahigh Bioproductivity from Algae”, Appl. Microbiol. Biotechnol. 76:969-975 (2007), which in incorporated herein by reference in it entirety and for all purposes.
(21) In other embodiments in which at least one factor for cultivating the algae (or other organism) is determined or controlled using a nanotechnological process or material, the factor is a chemical factor; in more specific embodiments, the chemical factor is monitored to optimize the growth and hydrocarbon production capacity of the provided algae (or other organism) using nanoscale materials and controls to develop mathematical models to control the introduction and maintenance of various nutrients and other growth inputs. In more specific embodiments, at least one nanoscale detection process, nanoscale membrane or nanoscale particle or other suitable nanoscale material is used to monitor the concentration of at least one chemical in the growth environment. Such membrane, particles, and materials are known to those having ordinary skill in the art, such as, by way of non-limiting examples, those described in U.S. Pat. Nos. 7,118,881; 7,163,659; 7,238,594; 7,336,859; 7,336,861; 7,387,877; 7,410,904; 7,425,749; 7,470,544; 7,655,269; 7,705,280; 7,733,479; and U.S. patent application Publication Nos. 20020192653, 20030207271, 20030215865, 20040106203, 20040182719, 20040214447, 20050070802, 20050124020, 20050161749, 20050176228, 20050221366, 20050279987, 20060004273, 20060068412, 20060169585, 20060180480, 20060183165, 20060207878, 20060270057, 20070012094, 20070025661, 20070116628, 20070145356, 20070147732, 20070231796, 20080024118, 20080054382, 20080094051, 20080095663, 20080129980, 20080135826, 20080204048, 20080212102, 20080280776, 20090010808, 20090014757, 20090147254, 20090215156, 20090220384, 20090278556, 20100020311, 20100021993, 20100060465, 20100129261, and 20100134286, each of which is incorporated herein in its entirety and for all purposes. In still other embodiments, such sensing is combined with trascriptomic or metabolomic information as described above to determine optimal growth conditions and monitor the progress of metabolic production of desired hydrocarbons. In more specific embodiments, the sensing just described determines the presence and optionally the amount of nutrients, salts, metabolites, and hydrocarbon products, and the pH and dissolved gas concentrations of the growth environment, or any subcombination thereof. In still more specific embodiments, the concentrations of one or more of these factors is used to develop mathematical models to optimize ambient reagent and biochemical concentrations and CO.sub.2 dosing.
(22) Returning to
(23) Following harvest, the hydrocarbons (“HC”) are produced by, extracted, or otherwise derived from the algae (or other organism) (1004). The processes for extracting and isolating hydrocarbons, usually in the form of oils, from algae (or other organism) are known to those having ordinary skill in the art. In some embodiments, the above-described functionalized nanoparticles and magnetic nanoparticles are used in conjunction to lyse the algae (or other organism) cells and release the desired hydrocarbons. For example, functionalized nanoparticles, either in solution or as part of a solid substrate, are bound to cell surface features (described above) of the algae (or other organism). Magnetic nanoparticles are used to create agitation sufficient to induce lysis of the algae (or other organism) cell walls, thereby causing release of the hydrocarbons. In some more specific embodiments, ultrasound energy is applied in conjunction with the magnetic nanoparticle agitation to facilitate cell lysis. The application of such ultrasound energy to facilitate cell lysis will be understood by those having ordinary skill in the art.
(24) In some embodiments, nanoparticles or nanofilters (or both) are used to facilitate extraction of the hydrocarbons. As noted above, the nanoparticles and nanofilters can be provided freely in solution or immobilized on a substrate, or in some combination thereof. Such materials and their use will be known by those having ordinary skill in the art. Examples of suitable nanofilters and their use can be found in U.S. Pat. No. 7,145,031, and in U.S. patent application Publication Nos.: 20090218285, 20030116510, 20090270609, and 20050084544; additional teachings are presented in Park, Eugene and Barnett, S. M. “Oil/Water Separation Using Nanofiltration Membrane Technology”, Separation Science and Technology 36(7):1527-1542 (2001); each of the foregoing patents and published patent applications is incorporated herein in its entirety and for all purposes.
(25) Once the lysis and collection of the released hydrocarbon is complete, the bound cellular debris and other biomass can be removed. Alternatively, the cellular debris and biomass can be removed prior to the extraction. Such operations will be familiar to those having ordinary skill in the art.
(26) The isolated hydrocarbon is then subjected to processing (1004) to make a desired biofuel or precursor thereof. Such processing will be familiar to those having ordinary skill in the art. In some embodiments, the present invention uses derivatized sub-micron beads, nanoparticles, or nanomembranes (or a combination thereof) to facilitate the conversion process. Examples of such nanoparticles include ZnO nanoparticles as described in Yan, S., et al., “Long Term Activity of Modified ZnO Nanoparticles for Transesterification”, Fuel, (In Press, Corrected Proof, Available online 1 June 2010); and U.S. patent application Publication Numbers 20080155888, 20090005582, and 20090155864; each of the foregoing being incorporated herein by reference in its entirety and for all purposes.
(27) 5.3.2 From Microbes
(28) A wide variety of bacteria and other microbes are known to have utility in producing biofuels (see, e.g., “Bacteria converted into ‘mini-factories’ for biofuels and vaccines”, ScienceDaily (Retrieved Jun. 25, 2010, from http://www.sciencedaily.com/releases/2010/06/100608211606.htm) and Antoni, D., et al., “Biofuels from Microbes”, Applied Microbiology and Biotechnology, 77(1):23-35 (November, 2007) (available online from SpringerLink Saturday, Sep. 22, 2007), each incorporated herein by reference in its entirety and for all purposes. Using the methods and materials discussed herein, biofuels from such bacteria can be made with the same advantages as discussed above for algae (or other organism)-produced biofuels. In some embodiments, thermophilic microbes, such as Ax99-59 or JH146, are used to produce biofuels. These microbes have been shown to produce 2-oxoisovalerate, a meatbolic precursor to the useful hydrocarbon isobutanol, directly from CO.sub.2, and thus are attractive sources of biofuel in view of their direct conversion of CO.sub.2 and lack of need for feedstocks.
(29) A exemplary method for generating biofuel from microbes (e.g., Ax99-59 or JH146) is illustrated in
(30) In more particular embodiments, the Ax99-59 or JH146 microbe (or both) is genetically or metabolically engineered to enhance, and in some embodiments selectively drive, productive capacity. In one embodiment, the enhancement includes providing one or more enzymes useful to enhance production of isobutanol from CO.sub.2, and more particular, from CO.sub.2 using a non-photosynthetic autotrophic pathway. Such methods and materials will be familiar to those having ordinary skill in the art. In other embodiments, the metabolic networks of the microbes are mapped using the methods and materials described above for monitoring metabolism and gene expression, and the metabolic pathways are then influenced or modified to enhance isobutanol production. Such techniques are familiar to those having ordinary skill in the art. In still other embodiments, electromagnetic and mechanical stresses are applied to the organisms to enhance isobutanol production.
(31) In other embodiments, the Ax-99-59 and JH146 microbes are engineered genetically to follow autotrophic metabolic pathways for the autotrophic conversion of 2-oxoisovalerate to isobutanol. In a more specific embodiment, the genetic engineering includes providing for the expression of the heterologous enzymes Fd oxidoredcutase and alcohol dehydrogenase. Such engineering can be achieved using methods and materials known to those having ordinary skill in the art. In still more specific embodiments, the above-described methods for metabolic tuning are applied to the engineered microbes to enhance the efficiency of conversion.
(32) In another exemplary embodiment, a different set of genetic modifications are applied to the microbial genomes to enable non-photosynthetic autotrophic conversion CO.sub.2 to, first, isobutyraldehyde (CH.sub.3CH(CH.sub.3)CHO), and second, to isobutanol by cloning genes for the necessary reduction of the aldehyde to the alcohol. In one embodiment, this is accomplished by engineering the bacteria to produce isovalerate decarboxylase and alcohol dehydrogenase. Such engineering can be achieved using methods and materials known to those having ordinary skill in the art. In still more specific embodiments, the above-described methods for metabolic tuning are applied to the engineered microbes to enhance the efficiency of biofuel production. In still more specific embodiments, the above-described methods for metabolic tuning and optimizing biofuel production are achieved by using tunable “nanoengineered” bioreactors that enable precision control or nanoscale control over various environmental parameters or “control knobs”.
(33) After selection, the microbes are grown under conditions effective to enable hydrocarbon production (
(34) In some embodiments, the genetic and metabolic performance of the microbes is monitored and controlled as described above; and the resulting information is used to create mathematical models that allow optimization of growth conditions and the production of the hydrocarbon (isobutanol in the case of the Ax99-59 or JH146 microbes), using methods and materials available to those having ordinary skill in the art. In one embodiment, Ax99-59 or JH146 microbes are tuned metabolically to enhance the efficiency of CO.sub.2 fixation and the expression of enzymes effective to convert acetyl-CoA to 2-oxoisovalerate.
(35) In some embodiments, the growth medium is monitored and controlled as described above to enhance the efficiency of isobutanol production.
(36) Following growth of the microbes, the hydrocarbon product (e.g., isobutanol in those embodiments in which the microbes is Ax99-59 or JH146) is extracted (2003), refined (2004), and processed (2005) as substantially as described above and apparent to those having ordinary skill in the art.
(37) 5.4 Devices for Making Biofuels Under Nanoscale Control
(38) In a second aspect, the present invention provides a tunable bioreactor configured to produce biofuels under nanoscale control also referred to herein as a “biorefinery”.
(39) One embodiment of such a bioreactor is shown at 3000 in
(40) Bioreaction chamber 3040 contains the organisms and materials necessary to produce the biofuel as described above. In addition, various nanoscale solid supports and magnetic nanoparticles as described above are provided as described above to enable the necessary mixing and lysing of the microbes to release hydrocarbon into the reaction mixture as described above. Chamber 3040 also includes various sensors, controls, pumps and filters that are not shown, but which will be understood by those having ordinary skill in the art.
(41) In one embodiment, the organisms are Ax99-59 or JH146 microbes (or both), either wild-type or genetically modified as described above. In a more specific embodiment, the organisms are Ax99-59 or JH146 microbes modified as described herein to produce isobutanol as described above. In such embodiments, chemical input storage tank provide all necessary nutrients as well as CO.sub.2 and H.sub.2 to enable the microbes to produce isobutanol. In a more particular embodiment, the microbes are bound to micron-sized particles or nanobeads arranged in a 2-D or 3-D matrix; more specifically, the matrix provides a relatively high packing density. In still more specific embodiments, microfluidic or nanofluidic channels are provided in the matrix to enable the motion of small molecules and dissolved gasses through the matrix to either the waste chamber or the supplemental or purification chambers described below. In some embodiments, magnetic nanoparticles are also provided, and chamber 3040 is configured to produce a magnetic field sufficient to induce the magnetic nanoparticles to create turbulence in the reaction medium sufficient to both mix the reactants and products in the chamber and cause separation of the isobutanol product from the waste products. (The process of mixing and separation using nanoscale methods or precision control processes is referred to herein as “nanoscale mixing” and “nanoscale separation”, respectively.) More specifically, the turbulence will cause at least a substantial fraction of the isobutanol to move into additional reaction and purification chambers (described below) while the cellular debris and other waste materials moves into waste chamber 3030, e.g., by moving the matrix into the waste chamber using a nanofilter or nanomembrane. Those having ordinary skill in the art will understand how to configure and provision the bioreaction chamber.
(42) In another embodiment, the Ax99-59 or JH146 are wild-type, and the intermediate 2-oxoisovalerate produced by the microbes passes through a supplemental reaction zone 3050. The supplemental reaction zone 3050 includes a supplemental reaction chamber 3054 containing additional enzymes (described above) that enable production of isobutanol from 2-oxoisovalerate as described above. The supplemental reaction chamber includes the additional enzymes described above mounted on particles or nanobeads, and is separated from the reaction chamber 3040 by a nanoscale separation process 3052 such that 2-oxoisovalerate rising from the reaction chamber 3040 enters the supplemental reaction chamber 3054 and is converted to isobutanol by the bound enzymes. The supplemental reaction chamber also includes nanoscale mixing processes, such as magnetic nanoparticles, and is configured to provide a magnetic field to induce turbulence and mixing. Provision of these elements can be accomplished using methods and materials known to those having ordinary skill in the art.
(43) The isobutanol product, whether produced directly in reaction chamber 3040 or in supplemental reaction chamber 3054, passes through a nanoscale separation process, such as nanofilter 3056, and into a purification chamber 3060, which includes filters and other materials sufficient to provide substantially pure isobutanol. Provision of these elements can be accomplished using methods and materials known to those having ordinary skill in the art.
(44) Some embodiments include an additional reaction zone 3070, separated from the purification chamber by a nanoscale separation process, such as a nanofilter (not shown), where additional bead-bound enzymes transform isobutanol into higher-order hydrocarbons, such as octanes and aromatic hydrocarbons. More specifically, bound enzymes convert isobutanol into isobutylene, which can be transformed by additional enzymes and reagents into a wide variety of products. For example, conversion of isobutylene into isooctene allows production of “bio-gasolene”, “bio jet fuel”, “biodiesel”, and similar products. Alternatively, the isooctene can be converted into aromatic compounds, including xylene, which can be further converted into terephtahlic acid and various polymers. Alternatively, the isobutylene can be converted into methyl methacyrlate (“MMA”), butyl rubber, and other compounds. The desired product pass through a nanoscale separation process, such as nanofilter 3080, and into a storage chamber 3090 from which he product can be retrieved (e.g., by pumping). Provision of these elements can be accomplished using methods and materials known to those having ordinary skill in the art.
(45) As noted above, the various reaction and storage chambers will include sensors and devices necessary to enable the mixing and collecting of materials and removal of debris. In some embodiments, most, if not all, of these operations are controlled by computers that collect and operate on data provided by the sensors. Thus, in some embodiments, the bioreactor provided by the invention is substantially automated. Provision of these elements can be accomplished using methods and materials known to those having ordinary skill in the art.
CONCLUSION
(46) Thus the advantages of the present invention will be apparent. Using the materials, methods, and devices described herein, important biofuels can be produced with high yield and low cost, and without the expense and risk inherent in obtaining the same hydrocarbons from geological petroleum sources. Importantly, the processes described herein for producing the biofuels consume CO.sub.2, a significant greenhouse gas. Thus, the present invention provides an important advance in so-called “carbon-neutral” energy sources and reducing an important greenhouse gass by creating hydrocarbon fuels from CO.sub.2, a principle greenhouse gas produced by combustion.
(47) The above description of the embodiments, alternative embodiments, and specific examples, are given by way of illustration and should not be viewed as limiting. Further, many changes and modifications within the scope of the present embodiments may be made without departing from the spirit thereof, and the present invention such changes and modifications.