U.S. patent application number 16/557430 was filed with the patent office on 2019-12-19 for process and system for producing glucose.
The applicant listed for this patent is Arturo SOLIS HERRERA. Invention is credited to Arturo SOLIS HERRERA.
Application Number | 20190382907 16/557430 |
Document ID | / |
Family ID | 51538200 |
Filed Date | 2019-12-19 |
United States Patent
Application |
20190382907 |
Kind Code |
A1 |
SOLIS HERRERA; Arturo |
December 19, 2019 |
PROCESS AND SYSTEM FOR PRODUCING GLUCOSE
Abstract
An electrochemical process and system for producing glucose are
described. The process and system allow for the production of
glucose from carbon dioxide and water, requiring only melanin, or a
precursor, derivative, analog, or variant of melanin, and
electromagnetic energy, such as visible or invisible light
energy.
Inventors: |
SOLIS HERRERA; Arturo;
(Aguascalientes, MX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SOLIS HERRERA; Arturo |
Aguascalientes |
|
MX |
|
|
Family ID: |
51538200 |
Appl. No.: |
16/557430 |
Filed: |
August 30, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14776135 |
Sep 14, 2015 |
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PCT/IB14/00315 |
Mar 12, 2014 |
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16557430 |
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61787338 |
Mar 15, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C25B 3/04 20130101; Y02P
20/135 20151101; Y02P 20/133 20151101; C25B 9/06 20130101; C25B
1/003 20130101 |
International
Class: |
C25B 3/04 20060101
C25B003/04; C25B 1/00 20060101 C25B001/00; C25B 9/06 20060101
C25B009/06 |
Claims
1. A process for producing glucose, the process comprising reacting
water and carbon dioxide gas dissolved therein in the presence of
at least one melanin device and a source of electromagnetic energy,
wherein the at least one melanin device consists of melanin and a
substrate, wherein the substrate is an inert material selected from
the group consisting of silica, plastic, and glass, the melanin
being held within the substrate to prevent the melanin from being
dispersed throughout the water, and the electromagnetic energy is
visible or invisible light energy having a wavelength of 200 nm to
900 nm, such that glucose is produced.
2. The process according to claim 1, further comprising
continuously dissolving carbon dioxide gas in the water.
3. The process according to claim 1, wherein the substrate of the
at least one melanin device is silica, such that a mixture of
melanin and silica is formed.
4. The process according to claim 1, wherein the process is carried
out at a temperature of 0.degree. C. to 25.degree. C.
5. The process according to claim 1, wherein melanin is selected
from natural melanin and synthetic melanin.
6. The process according to claim 1, wherein melanin is the only
water-electrolyzing material used in the process.
7. A system for producing glucose, the system comprising: (i) a
reaction cell for receiving water and carbon dioxide gas dissolved
therein, and at least one melanin device consisting of melanin and
a substrate, wherein the substrate is an inert material selected
from the group consisting of silica, plastic, and glass, the
melanin being held within the substrate to prevent the melanin from
being dispersed throughout the water; and (ii) a source of
electromagnetic energy, wherein the electromagnetic energy is
visible or invisible light energy having a wavelength of 200 nm to
900 nm, such that the electromagnetic energy is transmitted into
the reaction cell and is absorbed by melanin.
8. The system according to claim 7, wherein the reaction cell is
connected to a device for continuously injecting CO.sub.2 gas into
the reaction cell.
9. The system according to claim 7, wherein the reaction cell is a
closed reaction cell.
10. The system according to claim 7, wherein melanin is selected
from natural melanin and synthetic melanin.
11. The system according to claim 7, wherein melanin is the only
water-electrolyzing material present in the system.
12. The system according to claim 7, wherein the substrate of the
at least one melanin device is silica, such that a mixture of
melanin and silica is formed.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 14/776,135, filed Sep. 14, 2015, which is Section 371 of
International Application No. PCT/IB14/00315, filed Mar. 12, 2014,
which was published in the English language on Sep. 18, 2014 under
International Publication No. WO 2014/140740 A2, which claims
priority under 35 U.S.C. .sctn. 119(e) to U.S. Provisional Patent
Application No. 61/787,338, filed Mar. 15, 2013, and the
disclosures of which are herein incorporated by reference.
FIELD OF THE INVENTION
[0002] The invention relates to processes and systems for producing
glucose. In particular, the invention relates to the production of
glucose from water, carbon dioxide, electromagnetic energy, and
melanin, melanin precursors, melanin derivatives, melanin analogs,
or melanin variants.
BACKGROUND OF THE INVENTION
[0003] Glucose is a simple sugar having the general chemical
formula C.sub.6H.sub.12O.sub.6. Glucose is a basic molecule of the
food chain and is consumed by many organisms as a primary source of
energy. One well studied process that results in the production of
glucose is plant photosynthesis.
[0004] In general, photosynthesis is the process of converting
light energy into chemical energy. More specifically, through the
process of photosynthesis, plants use light energy to convert
carbon dioxide (CO.sub.2) and water (H.sub.2O) into oxygen
(O.sub.2) and glucose. Another critical component to this process
is the pigment known as chlorophyll. Chlorophyll initiates
photosynthesis by absorbing light energy or photons. For every
photon absorbed, chlorophyll loses one electron, creating a flow of
electrons which subsequently generates the energy necessary to
catalyze the splitting of water into hydrogen ions or protons
(H.sup.+) and O.sub.2. The resulting proton gradient is used to
generate chemical energy in the form of adenosine triphosphate
(ATP). This chemical energy is then used to convert carbon dioxide
and water into glucose.
[0005] Similar to chlorophyll, melanin is also classified as a
pigment. Melanin is composed of nitrogen, oxygen, hydrogen and
carbon, although the exact structure has not been fully elucidated.
Melanin is ubiquitous in nature and methods are also known in the
literature for synthesis of melanin. For many years, melanin had no
biological or physiological function attributed to it, other than
it being considered a simple sunscreen with a low protection factor
equivalent to that of a 2% copper sulfate solution. Melanin has
also been considered the darkest molecule because it is able to
absorb energy of almost any wavelength, yet it did not seem to emit
any energy. This was unique to melanin, and it contradicted
thermodynamic laws because other compounds capable of absorbing
energy, particularly pigments, emit a portion of the energy
absorbed. The electronic properties of melanin have thus been the
focus of attention for quite some time. However, melanin is one of
the most stable compounds known to man and, for a long time, it
seemed that melanin was unable to catalyze any chemical
reaction.
[0006] Recently, the intrinsic property of melanin to absorb energy
and utilize the absorbed energy to split and subsequently reform
the water molecule was discovered. Thus, melanin absorbs all
wavelengths of electromagnetic energy, including visible and
invisible light energy, and dissipates this absorbed energy by
means of water dissociation and its consequent reformation. A
photoelectrochemical process for separating water into hydrogen and
oxygen, using melanin, and analogs, precursors, derivatives, or
variants of melanin is described in U.S. Patent Application
Publication No. US 2011/0244345.
[0007] Without wishing to be bound by any theories, it is believed
that the reaction inside melanin occurs according to the following
Scheme I:
2H.sub.2O2H.sub.2+O.sub.24e.sup.- (I)
Upon the absorption of electromagnetic energy such as light energy
(visible or invisible), melanin catalyzes the dissociation of water
into diatomic hydrogen (H.sub.2), diatomic oxygen (O.sub.2), and
electrons (e.sup.-). Although the splitting of water into hydrogen
and oxygen consumes energy, the reaction is reversible, and in the
reverse process the reduction of oxygen atoms with diatomic
hydrogen to reform the water molecules liberates energy.
[0008] Thus, melanin is able to transform light energy into
chemical energy, analogous to the process by which plants use
chlorophyll to transform light energy into chemical energy during
photosynthesis. Therefore, by analogy, we have designated this
process "human photosynthesis." However, there are at least two
important distinctions between the water splitting reaction carried
out by melanin and that carried out by chlorophyll. The first is
that chlorophyll cannot catalyze the reverse process of reforming
the water molecule. The second is that the water splitting reaction
by chlorophyll can only occur in a living cell and with visible
light having a wavelength in the range of 400 nm to 700 nm. Thus,
the subsequent production of glucose can also only occur inside the
living cell. In contrast, melanin can split and reform the water
molecule outside of a living cell using any form of electromagnetic
energy, particularly with light energy (visible or invisible)
having a wavelength in the range of 200 nm to 900 nm.
BRIEF SUMMARY OF THE INVENTION
[0009] It is now discovered that upon the absorption of
electromagnetic energy, such as invisible or visible light energy,
melanin can split and reform the water molecule, and subsequently
catalyze a reaction that transforms carbon dioxide (CO.sub.2) and
water into glucose.
[0010] The invention relates to electrochemical processes and
systems for utilizing melanin, melanin precursors, melanin
derivatives, melanin analogs, and melanin variants to produce
glucose from carbon dioxide and water. According to embodiments of
the invention, melanin can be used to produce glucose from carbon
dioxide and water, additionally requiring only a source of
electromagnetic energy, such as invisible or visible light energy,
gamma rays, X-rays, ultraviolet radiation, infrared radiation,
microwaves, and radiowaves. Unlike the ability of chlorophyll to
convert light energy into chemical energy, which is subsequently
used to produce glucose in living cells by the process of
photosynthesis, melanin can be used to produce glucose via an
electrochemical process that can be performed outside a living
cell. Thus, until now, such a process for producing glucose has not
been replicated in the laboratory.
[0011] In one general aspect, the invention relates to an
electrochemical process for producing glucose
(C.sub.6H.sub.12O.sub.6). According to embodiments of the
invention, the electrochemical process comprises reacting water and
carbon dioxide gas dissolved therein, in the presence of at least
one melanin material and a source of electromagnetic energy. The at
least one melanin material is selected from melanin, melanin
precursors, melanin derivatives, melanin analogs, and melanin
variants. Because melanin is able to absorb electromagnetic energy
and transform this electromagnetic energy into usable chemical
energy, an external electric current is not required for the
production of glucose according to an electrochemical process of
the invention. According to a preferred embodiment, an
electrochemical process of the invention is a photoelectrochemical
process, and the source of electromagnetic energy is photoelectric
energy selected from visible and invisible light having a
wavelength in the range of 200 nm to 900 nm.
[0012] In another general aspect, the invention relates to an
electrochemical process for producing C.sub.nH.sub.2nO.sub.n
species, wherein n represents an C.sub.nH.sub.2nO.sub.n species
produced by a process of the invention is a glucose precursor, or
glucose itself. According to embodiments of the invention, the
electrochemical process comprises reacting water and carbon dioxide
gas dissolved therein, in the presence of at least one melanin
material and a source of electromagnetic energy, preferably
photoelectric energy selected from visible and invisible light
energy having a wavelength in the range of 200 nm to 900 nm.
[0013] In yet another general aspect, the invention relates to
systems for producing glucose and C.sub.nH.sub.2nO.sub.n species
from water, carbon dioxide, melanin and a source of electromagnetic
energy. According to embodiments of the invention, a system for
producing glucose via an electrochemical process comprises: [0014]
(i) a reaction cell for receiving water and CO.sub.2 gas dissolved
therein, and at least one melanin material, wherein the at least
one melanin material is selected from melanin, melanin precursors,
melanin derivatives, melanin analogs, and melanin variants; and
[0015] (ii) a source of electromagnetic energy, such that the
electromagnetic energy is transmitted into the reaction cell and is
absorbed by the melanin material.
[0016] The system for producing glucose according to embodiments of
the invention does not require any complicated operation or set-up,
and thus only requires a container for receiving water and CO.sub.2
gas dissolved therein, and at least one melanin material, as well
as a source of electromagnetic energy to provide the at least one
melanin material with sufficient amounts of energy to catalyze the
splitting and reformation of the water molecule and the subsequent
formation of glucose. According to a preferred embodiment, the
source of electromagnetic energy transmits visible or invisible
light energy having a wavelength between 200 nm and 900 nm into the
reaction cell.
[0017] The details of one or more embodiments of the invention are
set forth in the description below. Other features and advantages
will be apparent from the following detailed description and the
appended claims.
DETAILED DESCRIPTION OF THE INVENTION
[0018] All patents and publications referred to herein are
incorporated by reference. Unless otherwise defined, all technical
and scientific terms used herein have the same meaning as commonly
understood to one of ordinary skill in the art to which this
invention pertains. Otherwise, certain terms used herein have the
meanings as set forth in the specification.
[0019] It must be noted that as used herein and in the appended
claims, the singular forms "a," "an," and "the" include plural
references unless the context clearly dictates otherwise.
[0020] As used herein, the term "electrolysis of water" refers to
the process of splitting water molecules into oxygen and hydrogen.
As used herein, "water-electrolyzing material" refers to a
substance that is capable of splitting the water molecule into
oxygen and hydrogen. According to embodiments of the invention,
melanin materials including melanin (natural and synthetic),
melanin precursors, melanin derivatives, melanin analogs, and
melanin variants are water-electrolyzing materials.
[0021] As used herein, the term "melanin material" refers to
melanin, melanin precursors, melanin derivatives, melanin analogs,
and melanin variants including natural and synthetic melanin,
eumelanin, pheomelanin, neuromelanin, polyhydroxyindole, eumelanin,
alomelanin, humic acid, fullerenes, graphite, polyindolequinones,
acetylene black, pyrrole black, indole black, benzene black,
thiophene black, aniline black, polyquinones in hydrated form,
sepiomelanins, dopa black, dopamine black, adrenalin black,
catechol black, 4-amine catechol black, in simple linear chain
aliphatics or aromatics; or their precursors as phenols,
aminophenols, or diphenols, indole polyphenols, quinones,
semiquinones or hydroquinones, L-tyrosine, L-dopamine, morpholine,
ortho-benzoquinone, dimorpholine, porphyrin black, pterin black,
and ommochrome black.
[0022] According to embodiments of the invention, an
electrochemical process for producing glucose comprises reacting
water and CO.sub.2 gas dissolved therein, in the presence of at
least one melanin material and a source of electromagnetic energy.
Forms of electromagnetic energy suitable for use in an
electrochemical process of the invention include visible and
invisible light, gamma rays, X-rays, ultraviolet radiation,
infrared radiation, microwaves, and radiowaves. According to a
preferred embodiment, an electrochemical process according to the
invention is a photoelectrochemical process, wherein the source of
electromagnetic energy is photoelectric energy selected from
visible light and invisible (ultraviolet and infrared radiation)
light.
[0023] According to embodiments of the invention, the at least one
melanin material is selected from melanin, melanin precursors,
melanin derivatives, melanin analogs, and melanin variants. In a
preferred embodiment, the at least one melanin material is selected
from natural melanin and synthetic melanin.
[0024] According to embodiments of the invention, melanin can by
synthesized from amino acid precursors of melanin, such as
L-tyrosine. However, melanin materials can be obtained by any
method known in the art in view of the present disclosure,
including chemically synthesizing melanin materials and isolating
melanin materials from natural sources, such as plants and
animals.
[0025] According to another embodiment of the invention, an
electrochemical process can be carried out in the presence of at
least one melanin device. The melanin device is comprised of a
substrate and at least one melanin material, such that the melanin
material is held on or within the substrate. The melanin material
can be dispersed throughout the substrate or adsorbed onto the
substrate. Preferably, the substrate is transparent to allow for
increased transmission of electromagnetic energy in the form of
light energy, and therefore increased glucose production. A melanin
device can comprise one type of melanin material, or more than one
type of melanin material. For example, a melanin device for use in
the invention can comprise melanin and eumelanin. According to
another embodiment of the invention, more than one melanin device,
with each device comprising a different type of melanin material
can be used. For example, a first melanin device comprising melanin
and a second melanin device comprising eumelanin can both be used
in a process of producing glucose according to the invention.
[0026] A purpose of using a melanin device in an electrochemical
process of the invention is to prevent the melanin material from
dissolving in the water, diffusing through the water, or floating
freely throughout the water. The melanin device ensures that the
water retains its transparency and melanin is not lost during
replenishment of water or CO.sub.2 or removal of glucose. Thus, the
melanin device allows for the melanin material to remain in contact
with the water without being dissolved in the water. The substrate
of the melanin device can be any inert material, including, but not
limited to, silica, plastic, and glass. The melanin device can be,
for example, a melanin/silica plate, which can be made by combining
a cementing mixture of silica with an aqueous melanin solution.
Preferably, a melanin device for use in the invention is melanin
mixed with silica.
[0027] According to embodiments of the invention, the melanin
device can take on any size or shape, including but not limited to
a rod (cylindrical), plate, sphere, or cube-shape. At least one
melanin device can be used, but the number of melanin devices, or
the size or shape of the melanin devices, is not limited in any
way. The rate of the reaction will be controlled by the size,
shape, surface area, amount of melanin material and number of
melanin devices used in the reaction. According to a preferred
embodiment, the size, shape and number of melanin devices are
selected based on the desired reaction rate of the electrochemical
process. For example, using a larger number of melanin devices will
result in a faster rate of glucose production. As another
illustrative example, a larger amount of melanin material in the
melanin device will result in a faster rate of glucose
production.
[0028] An electrochemical process according to embodiments of the
invention will be initiated when the melanin material absorbs
electromagnetic energy and catalyzes the electrolysis of water into
H.sub.2 and O.sub.2. According to one embodiment of the invention
(batch process), carbon dioxide gas is dissolved in the water only
once, prior to the initiation of the photoelectrochemical
process.
[0029] According to another embodiment (continuous process), the
photoelectrochemical process further comprises continuously
dissolving CO.sub.2 gas in the water to continuously replenish the
CO.sub.2 gas as it is consumed and converted to glucose. Any
suitable method for continuously dissolving CO.sub.2 gas in the
water can be used. For example, the CO.sub.2 gas can be
continuously injected into the water by pipes or tubes connected to
a gas pump. The pipes or tubes can be made of any material that is
inert and substantially impermeable to CO.sub.2 gas including, but
not limited to, polyethylene.
[0030] According to a particular embodiment of the invention, a
process for producing glucose is a photoelectrochemical process
requiring a source of photoelectric energy. Preferably, the source
of photoelectric energy is either visible or invisible light having
a wavelength ranging from 200 nm to 900 nm. In a more preferred
embodiment, the source of photoelectric energy is natural
light.
[0031] According to another embodiment of the invention, the
electrochemical process can be performed at room temperature
(approximately 25.degree. C.), preferably at a temperature below
room temperature in the range of 0.degree. C. to 25.degree. C., and
more preferably at a temperature ranging from 2.degree. C. to
8.degree. C. Although lower temperatures can decrease the turnover
rate of splitting and reforming the water molecules, a lower
temperature incubation preserves the CO.sub.2 gas bubbles
introduced at the start of the process and eliminates the need to
continuously inject CO.sub.2 gas into the water. Thus, using lower
temperatures has the main advantage of rendering the
electrochemical process technically simpler to execute.
[0032] An electrochemical process according to the invention can
further comprise a step of isolating the glucose obtained from the
reaction of carbon dioxide, water, and the at least one melanin
material. As an illustrative example, glucose can be isolated by
evaporating the aqueous reaction solution. However, glucose can be
identified and measured without being isolated by, for example,
spectrophotometry.
[0033] The invention also relates to an electrochemical process for
producing C.sub.nH.sub.2nO.sub.n species, wherein n represents an
integer. Preferably n is 1, 2, 3, 4, 5, or 6, such that the
C.sub.nH.sub.2nO.sub.n species is a glucose precursor, or glucose
itself. According to embodiments of the invention, an
electrochemical process for producing C.sub.nH.sub.2nO.sub.n
species can be the same as that used to produce glucose, and
comprises reacting water and CO.sub.2 gas dissolved therein, in the
presence of at least one melanin material and a source of
electromagnetic energy. Preferably, the source of electromagnetic
energy is photoelectric energy selected from visible light and
invisible (ultraviolet and infrared radiation) light. Other
embodiments of a process for producing C.sub.nH.sub.2nO.sub.n
species according to the invention can be the same as those
described for an electrochemical process for producing glucose
according to the invention. Preferably, an electrochemical process
for producing C.sub.nH.sub.2nO.sub.n species is a
photoelectrochemical process.
[0034] The precise mechanism by which melanin is able to use
electromagnetic energy to produce glucose, glucose precursors, and
other C.sub.nH.sub.2nO.sub.n species from CO.sub.2 and water in an
electrochemical process according to embodiments of the invention
is not yet fully understood. Without wishing to be bound by any
theories, it is believed that melanin absorbs the electromagnetic
energy, promoting conversion of low energy electrons to high energy
electrons. The high energy electrons are transferred by mobile
electron carriers within the melanin material. This electron
transfer releases energy and establishes a proton gradient
sufficient to initiate the splitting of water into diatomic
hydrogen (H.sub.2) and diatomic oxygen (O.sub.2) along with the
release of four high energy electrons. Thus, melanin releases
molecules of H.sub.2 and O.sub.2, as well as a flow of high energy
electrons in all directions, controlled by diffusion. The released
hydrogen and high energy electrons have different types of energy,
and it is thought that both types of energy play a role in the
conversion of CO.sub.2 and water into glucose and other
C.sub.nH.sub.2nO.sub.n species. Although the splitting of water
into H2 and O.sub.2 consumes energy, the reaction is reversible and
the reduction of O.sub.2 with H.sub.2 to reform the water molecules
liberates energy. Thus, after the water molecule is split, the
water molecule must be reformed in order to supply energy to the
glucose production reaction that occurs from the fusion of CO.sub.2
and water.
[0035] Many factors will affect the rate and efficiency of an
electrochemical process for producing glucose according to
embodiments of the invention. These factors include, but are not
limited to, the amount of energy released by splitting and
reforming the water molecules, the entropy of the dissolved
CO.sub.2 gas, the amount of dissolved CO.sub.2 gas, temperature,
pressure, the wavelength of electromagnetic energy supplied to the
reaction, and the amount of electromagnetic energy absorbed by the
melanin material.
[0036] According to a preferred embodiment of the invention, an
electrochemical process for producing glucose is performed under
sterile conditions, meaning that there is substantially no bacteria
present in the reaction. Because bacteria can consume glucose, the
presence of bacteria can decrease the amount of glucose produced by
an electrochemical process according to the invention. Reactions
can be sterilized by any method known in the art in view of the
present disclosure including, but not limited to, filter
sterilization and heat sterilization.
[0037] The dissociation and reformation of the water molecule to
produce energy that is subsequently used to produce glucose from
carbon dioxide and water can by catalyzed by at least one melanin
material, wherein the at least one melanin material is the only
water-electrolyzing material present in the reaction. Thus, in
particular embodiments of the invention, the at least one melanin
material is the only water-electrolyzing material used in an
electrochemical process for producing glucose. According to a
preferred embodiment, melanin (synthetic or natural) is the only
water electrolyzing material used in a process for producing
glucose.
[0038] Another aspect of the invention provides a system for
producing glucose via an electrochemical process. According to
embodiments of the invention, the system is comprised of a reaction
cell and a source of electromagnetic energy. As used herein, the
term "reaction cell" refers to any container that can receive and
hold water and carbon dioxide gas dissolved therein. The reaction
cell can take on any shape, and can be made of any suitable
material including, but not limited to, plastics, glass, and any
other materials that allow for the transmission of the desired
wavelengths of electromagnetic energy into the reaction cell, such
that the electrochemical process can occur. The material of the
reaction cell is preferably transparent to allow for the
transmission of visible light. The material of the reaction cell is
also preferably substantially impermeable to carbon dioxide.
[0039] According to another embodiment, the reaction cell is a
closed reaction cell. A closed reaction cell is sealed to prevent
carbon dioxide gas from escaping the reaction cell, and can be made
of any suitable material as discussed above. Preferably, the
reaction cell is closed. The reaction cell receives water and
CO.sub.2 gas dissolved therein, and at least one melanin material.
The at least one melanin material is selected from melanin, melanin
precursors, melanin derivatives, melanin analogs, and melanin
variants, and is preferably melanin (synthetic or natural). In
another embodiment of the invention, a system comprises the at
least one melanin material as part of at least one melanin device,
the device comprised of a substrate and a melanin material as
discussed above. Preferably, the melanin device comprises melanin
(natural or synthetic) and silica.
[0040] A system according to the invention is preferably sterile,
and lacks the presence of any bacteria. The system, including one
or more of its component parts (reaction cell, tubing, etc.) can be
sterilized according to any method known in the art that eliminates
or kills bacteria, such as by applying heat, chemicals,
irradiation, pressure, or filtration.
[0041] According to embodiments of the invention, the energy
provided by the source of electromagnetic energy to the reaction
cell is transmitted through the reaction cell, such that it is
absorbed by the melanin material. In a preferred embodiment, the
source of electromagnetic energy provides invisible or visible
light energy having a wavelength between 200 nm and 900 nm to the
reaction cell.
[0042] According to another embodiment of the invention, the system
can further comprise a device for continuously injecting CO.sub.2
gas into the reaction cell. The device can be, for example, a gas
pump. The device can be connected to the reaction cell by pipes or
tubes. If the reaction cell is closed, the device is preferably
connected in such a way that allows for the closed reaction cell to
remain sealed to prevent CO.sub.2 gas from escaping. Thus, using a
closed reaction cell has the advantage of eliminating the need to
continuously inject carbon dioxide into the reaction cell, provided
that the container is sufficiently sealed to prevent the carbon
dioxide gas from escaping.
[0043] According to embodiments of the invention, a system for
producing glucose via an electrochemical process can also be used
to produce C.sub.nH.sub.2nO.sub.n species. Preferably the
C.sub.nH.sub.2nO.sub.n species is a glucose precursor, wherein n
represents 1, 2, 3, 4, or 5.
[0044] The electrochemical process and system for producing glucose
according to embodiments of the invention, in addition to CO.sub.2
gas dissolved in water, requires only the presence of a melanin
material and electromagnetic energy, preferably photoelectric
energy, and more preferably light energy, and thus is
environmentally friendly because no source of external energy,
other than that present in the natural surroundings is required.
Furthermore, no complex setup or maintenance is required. The only
maintenance required is the replacement of the water and dissolved
CO.sub.2 gas once CO.sub.2 has been consumed and transformed into
glucose. Because melanin is one of the most stable molecules known
to man, having a half-life estimated to be on the order of millions
of years, the melanin material or melanin device can be used for
decades before it needs to be replaced.
[0045] In a preferred embodiment, the at least one melanin material
in the system is melanin (natural or synthetic). In another
preferred embodiment, melanin is the only water-electrolyzing
material present in the system.
[0046] The electrochemical process and system for producing glucose
according to embodiments of the invention have at least two
important applications. The first application is the production of
glucose, as described above, which is a basic molecule of the food
chain. The second application is related to the control of
atmospheric CO.sub.2. According to embodiments of the invention,
the production of glucose requires the consumption of CO.sub.2.
Thus, the invention further provides a method for reducing
atmospheric CO.sub.2 levels.
[0047] Carbon dioxide (CO.sub.2) is the principal greenhouse gas
that results from human activities, and the concentration of
atmospheric CO.sub.2 is increasing at an accelerating rate,
contributing to global warming and climate change. Although the
upper safety limit for atmospheric CO.sub.2 has been set at 350
parts per million (ppm), atmospheric CO.sub.2 levels have remained
above this limit since early 1988. In addition, paleo-climate
evidence and ongoing climate change suggest that CO.sub.2 levels
will need to be reduced in order to preserve the planet in a state
in which life on Earth has adapted to.
[0048] Furthermore, calculations by NASA researchers indicate that,
despite unusually low solar activity between 2005 and 2010, Earth
continued to absorb more energy than it returned to space. Thus,
climate stabilization will also require a restoration of the
Earth's energy balance as well as a reduction of CO.sub.2 levels.
In other words, Earth will need to radiate as much energy to space
as it absorbs from the sun in order to slow down global
warming.
[0049] Therefore, new methods for controlling the level of
atmospheric CO.sub.2 and for consuming absorbed solar energy are
greatly needed. In a photoelectrochemical process according to
embodiments of the invention, only light energy and at least one
melanin material such as melanin (synthetic or natural), a melanin
analog, or melanin precursor are required to convert CO.sub.2 and
water into glucose. Thus, both CO.sub.2 and solar energy are
consumed in the production of glucose by a photoelectrochemical
process of the invention, which will contribute to a reduction of
CO.sub.2 levels while simultaneously using absorbed solar
energy.
EXAMPLES
Example 1: Dissociation and Reformation of the Water Molecule
Catalyzed by Melanin
[0050] Two 1 liter closed containers (closed reaction cells) made
of polyethylene terephthalate (PET), were formed under sterile
conditions each containing 1 liter of purified water. CO.sub.2 gas
was dissolved in the water in each container at an initial pressure
of 5 atm, and melanin mixed with silica was placed in one of the
two containers. The containers were exposed to visible light for
six weeks and incubated at a temperature of about 2.degree. C. to
8.degree. C. (35.6.degree. F. to 46.4.degree. F.).
[0051] After 5 days, deformation of the plastic packaging of the
container containing melanin mixed with silica was observed. In
contrast, after 6 weeks of exposure to visible light, the plastic
packaging of the container that did not have any melanin mixed with
silica showed no visible deformation.
[0052] The results of the experiment support the claim that melanin
has the intrinsic ability to dissociate and reform the water
molecule in the presence of light energy. This dissociation and
reformation of the water molecule produced a vacuum, as indicated
by the deformation of the plastic packaging of only the closed
container that contained melanin. The energy that is produced from
splitting and reforming the water molecule catalyzed by melanin can
subsequently be used to convert carbon dioxide and water into
glucose.
Example 2: Production of Glucose from CO.sub.2 Dissolved in Water,
Melanin and Light Energy
[0053] Ten sealed, 3 liter closed containers (closed reaction
cells) made of polyethylene, were formed under sterile conditions
each containing 1800 mL of purified water. CO.sub.2 was dissolved
in the water in each container under a pressure of approximately
2.20 PSI, in sufficient amounts such that numerous bubbles of
CO.sub.2 gas were easily observed. Five of the containers served as
the control group and contained no melanin device, and the other
five containers served as the experimental group. For the
experimental group, plates of melanin mixed with silica were placed
at the bottom of each container. The melanin/silica plates were
made by combining a cementing mixture of silica with an aqueous
solution of melanin. The melanin used was chemically synthesized in
the laboratory.
[0054] The containers of both the control and experimental groups
were placed in a refrigerator and incubated at a temperature
ranging between 2.degree. C. to 8.degree. C. (35.6.degree. F. to
46.4.degree. F.) for four weeks. The purpose of refrigerating the
containers was to preserve the CO.sub.2 gas initially dissolved in
the water. This eliminated the need for continuous manipulation of
the containers by having to dissolve CO.sub.2 in the water either
continuously or several times over the course of the experiment.
Because the refrigerator was composed of metal walls, the source of
energy supplied to the containers was mostly invisible light
present within the refrigerator. The containers were kept sealed
throughout the course of the experiment and the visual observance
of CO.sub.2 gas bubbles in the control group containers throughout
the four week incubation confirmed that the containers were
adequately sealed.
[0055] The dissolved CO.sub.2 gas bubbles were observed daily. At
the end of the first week, the CO.sub.2 bubbles in all of the
control group containers were still present and showed no change
from the start of the experiment. On the other hand, in all of the
experimental group containers, the dissolved CO.sub.2 bubbles
disappeared completely within a few hours. This indicated that
carbon dioxide was being consumed, but only in the presence of
melanin. The experiment was continued for four weeks, even though
the carbon dioxide bubbles in the experimental containers had
disappeared within a few hours, to determine if any other product
or sediment was formed. At the end of the fourth week, the seals of
each container in both the experimental and control groups were
broken under sterile conditions and a 10 mL sample of water was
removed from each container. It should also be noted that at the
end of the fourth week, the carbon dioxide in the containers of the
control group showed no change from the start of the
experiment.
[0056] The 10 mL samples of water removed from each of the control
group and experimental group containers were noted to be both
transparent and odorless. For the experimental group, no sediment
was observed in the samples of either group, indicating that the
melanin had not dispersed from the melanin/silica plates.
Additional parameters, including the density, pH, and glucose
concentration were measured in each sample.
[0057] The glucose concentration in each sample was determined by
spectrophotometry using a standardized glucose oxidase (GOD) assay.
Briefly, each sample was treated with glucose oxidase to oxidize
glucose, producing gluconate and hydrogen peroxide. The hydrogen
peroxide was then oxidatively coupled with 4-amino-antipyrene
(4-AAP) and phenol in the presence of peroxidase, producing a red
dye quinoneimine. The absorbance of quinoneimine at 505 nm, which
is directly proportional to the concentration of glucose, was then
measured and used to determine the concentration of glucose in the
sample. The results are listed below in Table 1.
TABLE-US-00001 TABLE 1 Control Group Experimental Group Density
(g/cm.sup.3) 1.005 1.000 pH 7.5 6.5 Glucose Concentration (mg/dL)
0.0 0.1-0.12
[0058] The results of the above experiment demonstrate that glucose
can be produced from carbon dioxide and water, requiring only
melanin and electromagnetic energy, such as invisible light.
[0059] It will be appreciated by those skilled in the art that
changes could be made to the embodiments described above without
departing from the broad inventive concept thereof. It is
understood, therefore, that this invention is not limited to the
particular embodiments disclosed, but it is intended to cover
modifications within the spirit and scope of the invention as
defined by the appended claims.
* * * * *