Feeding The Growing Population With Starch Produced From Carbon Dioxide
Imagine if you had to choose between a place to live and food to eat.
Sounds like I’m describing the struggle of people in abject poverty, right?
But, the crazy thing is, if every single person on Earth ate the average diet of an American, all habitable land on Earth would need to be used for agriculture, and we would still be 38% short of land needed to meet this demand.
The global population is projected to increase to 9.8 billion people by 2050, increasing global food demand by 60% from current levels.
50% of habitable land is already allocated to agriculture, with the rest being forests and well, our homes.
But, even if we had all the land needed to sustain the growing population, we have an even larger problem at hand: climate change.
Currently, over 50% of consumed calories are derived from as little as three crops: rice, maize, and wheat. But, the average crop yield for maize is projected to decrease by 24% by 2030 due to climate change.
As crop yields fluctuate due to climate change and populations rise exponentially, more and more habitable land will be allocated for agriculture. This causes deforestation, habitat loss, and water shortages while accelerating climate change.
Agriculture accounts for approximately 80% of deforestation, and 11% of all global greenhouse gas emissions.
Where do current solutions fall short?
Renewables have become the center of attention as a solution to climate change. But, the current capacity of renewable resources meets only a fraction of the growing energy needs. China, the country that emits 28% of all global emissions, is planning to expand coal power by 247 gigawatts in the coming future.
What about carbon capture? Scaling-up carbon capture and storage technologies would consume more energy than the energy that created the carbon dioxide in the first place. Carbon capture and utilization technologies convert carbon dioxide into fuels that return carbon dioxide back into the atmosphere when burned. We cannot wait for a future without fossil fuels or rely on current carbon capture solutions before climate change becomes irreversible.
But, the situation for food shortage is even more urgent.
The current solutions rely on the public to transition away from meat, increase crop yield, and decrease food waste. But, all of these strategies are only incrementally closing the gap between food production and demand—a gap that is growing every day. If we want to successfully end food insecurity, we need a radically better solution.
So what do we solve first, climate change or food shortage?
What if I told you that we could solve both, with one solution?
Introducing Enzumos Labs
My team and I at Enzumos Labs, have developed a plan to feed the growing population using carbon dioxide with no extra energy input and without depleting agricultural lands. Here’s how.
Our solution consists of five steps:
- Harnessing electricity from waste heat generated by coal plants using thermoelectric generators
- Converting water into hydrogen through the electrooxidation of ammonia
- Capturing carbon dioxide directly from coal plants using surface diffusion
- Converting carbon dioxide and hydrogen into methanol
- Converting methanol to amylose starch through a cascading enzymatic system
Step 1: Harnessing Electricity From Waste Heat
In 2020, the energy of waste heat generated in the U.S. was roughly equal to the total energy of electricity that 200 million people in the US use in a whole year.
Virtually all industrial processes generate waste heat, with one of the largest producers being the petroleum and coal industries.
Based on the ICF International report, the petroleum and coal industry has reported producing 1,032 trillion BTUs of waste heat annually — equivalent to approximately 302,500 gigawatts — with the heat streams generally hotter than 450°F (232°C).
We are going to harness waste heat from coal plants using thermoelectric generators, producing approximately 80 to 100 kWh of energy per square meter of infrastructure.
What is Thermoelectricity?
Thermoelectricity is the production of electricity directly from heat, without the need for steam turbines.
The conversion of heat to electricity occurs when the temperature difference between one side of a material and the other can produce an electric current (this is called the Seebeck effect).
The two main carriers of energy in semiconductors are electrons and holes. When semiconductors are heated, electrons in covalent bonds can break free — becoming conduction electrons — and move around generating a current. When electrons break loose, they leave behind a hole that is able to accept electrons. When electrons fill the hole, the hole moves to a different position, also generating a current (you can think of this as a moving positively charged particle).
Thermoelectric generators consist of two semiconductors—an n-type semiconductor (donor) and a p-type semiconductor (acceptor)—connected by a metal bridge that allows electrons to flow between the materials.
An n-type semiconductor has an excess of negatively-charged conduction electrons (hence the name n-type), meaning when heated, electrons move to the cold side of the material without leaving behind many holes.
A p-type semiconductor has an excess of positively-charged holes and few conduction electrons (hence the name p-type), meaning when heated, these holes (you can think of them as positive particles) move toward the cold side of the material, causing the cold side to have a high-density of holes.
When one end of both materials is heated, the electrons from the n-type material move toward the holes in the p-type material (you can think of the electrons trying to fill the empty holes in order to become neutral). This generates an electric current.
The fundamental problem in creating efficient thermoelectric materials is that they need to be good at conducting electricity, but not at conducting thermal energy.
This allows one side to get hot while the other gets cold without equalizing in temperature. The majority of materials, however, are both electric conductors and heat conductors — making the thermoelectric effect to be too low to be useful.
Some inorganic metals have enhanced thermoelectric effects, but these materials have several disadvantages that inhibit them from being implemented in commercial settings, including their high cost, toxicity, scarcity, and heavy metal pollution.
For this reason, new nano-engineered organic materials (carbon materials) that are able to have their thermal and electric properties fine-tuned to meet the needs of thermoelectric systems have been created.
Specifically, flexible nanocomposite thermoelectric materials have been of interest for their high conductivity, lightweight, easy handling, and low thermal conductivity.
Enough with the theory, how are we actually implementing this?
In our system, we are using simple nanocomposite films based on polyvinyl alcohol (PVA) and carbon quantum dots (CQDs) nanoparticles for the p-type semiconductor and a magnesium compound for the n-type semiconductor.
The generator is then used to collect waste heat directly from coal plants.
A coal plant works like this: powdered coal is burned in a furnace, heating up water that is moved to the boiler to evaporate into high-pressure steam. The steam is converted into mechanical energy through a steam turbine. In this power generation process, there are several places that release recyclable waste heat:
- Continuous blowdown systems. The remaining boiler water that didn’t turn into steam is drained into the sewage. The drained water has a temperature of over 150°C which can be converted into electricity.
- Exhaust flue gas from boilers. Flue gas is produced from boilers at a temperature of 120–140°C, which accounts for 4–8% of the total boiler heat produced from coal burning. The exhaust flue gas alone stores 10–30 MW (million watts) of heat per boiler.
- Exhaust steam from turbines. Exhaust steam from condensing turbines can be turned into electricity. Often, the steam is condensed in offshore coal plants by cooling with seawater. The temperature difference between exhaust steam and seawater can generate 300 MW of electricity per high-capacity coal plant.
Step 2: Converting Water Into Hydrogen
In order to produce starch, we need hydrogen.
Currently, hydrogen is produced in one of two ways:
Blue hydrogen is the production of hydrogen using natural gas while storing the generated carbon dioxide underground using carbon capture.
Green hydrogen is the production of hydrogen through a process called water electrolysis (splitting water molecules into hydrogen and hydroxide) using renewable energy. However, the 30% higher cost of green hydrogen makes it economically disadvantageous against using natural gas.
The conventional water electrolysis reaction involves applying an electric current to water molecules to initiate a two-part reaction:
- After applying an electric current, hydroxide ions (OH-) in a basic solution decompose to produce oxygen (O2) and water (H2O), releasing free electrons (e-).
2. With the help of the electric current, water molecules gain the free electrons produced in the first reaction and decompose to form hydrogen gas (H2)—the desired product—and hydroxide ions (OH-)—which are used to replenish the OH- concentration lost in the first reaction.
The fundamental challenge with traditional water electrolysis is its high energy demand and low energy conversion efficiency. A bulk of the energy consumed is used to oxidize OH- to produce free electrons, a highly inefficient process. With producing hydrogen as the main goal in mind, spending extra energy in the oxidation step of the process is a waste of energy.
Organic compounds, an alternative to hydroxide, have been of interest recently because they oxidize at a much lower energy input.
In our process, we are using ammonia (NH3) as our organic compound.
At the anode, ammonia — instead of hydroxide — is oxidized to produce electrons (e-), nitrogen (a harmless, nonreactive gas), and water.
The second step is identical to the traditional water electrolysis reaction:
From previous research, water electrolysis with ammonia (0.02 V voltage requirement) uses 95% less energy input than conventional water electrolysis with hydroxide (1.23 V voltage requirement), with the only byproducts being water and harmless nitrogen gas (which takes in harmful ammonia as feedstock).
Collecting Ammonia
A high concentration of ammonia is found in sewage water from municipal waste facilities. In particular, past research has focused on secondary sludge (another word for sewage), which is wastewater after filtering out organic biomass.
To isolate ammonia from the sludge, a solution of the sludge would be submerged with nonmetal/metalloid-based minerals with 3D pore structures called zeolites. Zeolites drive an ion exchange (IE) reaction, where ammonium ions (NH4+ or ammonia dissolved in water) enter the cavities of the zeolite structure. Before the reaction, the zeolite will be supplemented with sodium chloride (NaCl) solution to fill up the cavities of the zeolite with Na+ ions to produce zeolite-Na+. Upon contact with this sludge, the Na+ ions in the zeolite would escape the cavities of the zeolite, providing space for ammonium (NH4+) ions to enter the cavities.
Among zeolite types, we will be using a natural zeolite called bentonite I, which removes ammonium at an efficiency of 55.7% when treated with 1 mol/L of NaCl solution before the reaction.
The reaction would take place for about 2–3 hours until the zeolite is saturated with NH4+ before being removed from the sludge. To harvest the ammonium, the zeolite would be flushed with a stripping acid composed of a solution containing 65% nitric acid (HNO3), grabbing onto NH3 as it passes through the cavities of the zeolite. The resulting ammonia gas in the HNO3 solution would be separated out through a vacuum stripping process.
The sludge after the removal of NH3 will undergo the rest of the steps for sewage processing. As the wastewater is released into the ecosystem after the series of treatment steps, removing toxic NH3 from the sewage beforehand would alleviate the environmental impacts of pollution from sewage water disposal. We will also use the resulting water produced after the full sewage treatment process in the water-splitting process to produce hydrogen.
Producing Hydrogen
The hydrogen production reaction would occur in a bioreactor with two compartments separated by an anion exchange membrane (AEM) that allows the transfer of OH- from the reduction reaction of H2O to the oxidation reaction of NH3. We will be using a membrane produced by coating carbon papers with Nickel that catalyzes the transfer of OH- through the carbon paper.
The anode (compartment where oxidation of NH3 occurs) would consist OH- ions (produced from a solution containing 20–30% potassium hydroxide), and ammonia.
The cathode (where H2O is reduced to form H2) will contain water produced after the full treatment of the sewage after the removal of NH3. Recycled water from sewage is much cheaper and safer than other methods of acquiring water, such as desalination of seawater, which requires more energy input and therefore is more expensive.
The electrons needed to initiate the reduction reaction in the cathode would be transferred from the oxidation reaction in the anode through two connected NiCu/CP electrodes (which was shown to yield the highest reaction rate in this study) dipped into the anode and cathode.
The hydrogen produced in the cathode would be extracted by a vacuum pump to be transported to step 4 of the process.
Step 3: Capturing Carbon Dioxide
Since direct air carbon capture technologies have not been developed enough to be cost-effective or efficient enough for our purposes, we will capture carbon dioxide directly from coal plants, an industry with a high economic incentive for going net zero.
In the United States, coal plants account for 54% of all carbon dioxide emissions from the electricity sector, while only accounting for 20% of total electricity production.
With developments in technology and government policy, coal plants have decreased their emissions of harmful toxins including nitrogen oxide, sulfur dioxide, and ash by approximately 90%, however, carbon dioxide emissions are still high.
The exhaust pipes of coal plants release three types of gases: carbon dioxide, water vapor, and nitrogen gas. To ensure high-purity carbon dioxide is captured and inputted into the proceeding step of our system, we will filter out the water vapor and nitrogen gas in two steps:
- Water vapor will be converted into water through condensation, leaving only the gaseous nitrogen and carbon dioxide mixture.
- Using a cellulose acetate membrane, we are removing nitrogen gas from the mixture through surface diffusion. Cellulose acetate has a high affinity (attraction) to nitrogen, causing nitrogen to be adsorbed (held on to the surface) and moved into the spores of the membrane, while carbon dioxide is left behind.
- The high-purity carbon dioxide will be captured from the exhaust and stored in aluminum carbon dioxide tanks to be used as inputs for the next step of our system.
Step 4: Producing Starch from Carbon Dioxide and Hydrogen Fuel
Using a cascading enzymatic system, we will convert carbon dioxide and hydrogen gas into amylose starch at a rate of 22 nanomoles per minute per milligram of total catalyst and proteins, a rate approximately 8.5 times faster than starch synthesis through the Calvin cycle in maize.
But first, let’s understand enzymes and how they function.
What are enzymes?
Enzymes are proteins consisting of amino acids that specialize in catalyzing chemical reactions in the natural world. Enzymes are masters at initiating specific reactions using specific reactants due to their high selectivity and increasing the speed at which chemical reactions take place without consuming extra energy.
The majority of complex biological reactions require a large amount of energy to break their energy barrier for the reaction to occur. In biological systems, the energy needed to catalyze fundamental reactions — in the form of heat—would severely damage or kill the cell. This is where enzymes come in.
Enzymes work by binding to their specific substrates (reactants) with their active site and holding them in the required configuration to lower the energy of the transition state—the unstable and highly reactive state required for the substrates to react with each other. There are two ways enzymes catalyze reactions:
- They remodel the chemical structure of the substrate to produce a new product
- They break down one substrate into multiple products
- They combine multiple substrates into a larger molecule
Different enzymes have different active sites—formed by folded proteins—with a defined shape that determines their specificity (ability to react with only specific substrates).
Enzymes are crucial to cascading reaction systems because it allows multiple enzymes in one reaction vessel to carry out only their assigned reactions and prevent reacting with other substrates or substances that can decrease the efficiency of the system and produce unwanted products. Enzymes are also able to remain unchanged after a reaction, allowing them to perform thousands of reactions back-to-back.
Enzymes are the foundation of all life on Earth, but they have their limitations.
Genetically Modifying Enzymes
We are enabling the large-scale production of cell-free synthetic enzymes through directed enzyme evolution.
Directed enzyme evolution is a widely known method of synthetically engineering enzymes with enhancements of their existing features, an invention that won the 2018 chemistry Nobel prize. The current challenge with engineering completely new enzymes lies in the complexity of enzyme composition and the lack of understanding of the exact compositions that will help achieve the desired goal.
Directed evolution begins with a natural enzyme that already performs similar functions and has similar properties as the desired enzyme. Random changes — called mutations — are introduced to the gene that encodes the enzyme, which generates a range of slightly different enzymes. Finally, the mutated enzyme with the highest performance in the desired tasks is used for further rounds of evolution. The common goals of directed evolution are to tailor enzymes to operate in new reaction conditions, optimize enzymes’ catalytic activity towards new substrates, and make enzymes catalyze new chemical reactions.
The general methodology for directed evolution cell-free (in vitro) relies on several steps:
- Choosing an enzyme that has similar properties or functions to the desired enzyme.
- Generating a diverse library of enzymes by random mutagenesis (completely random mutations), focused mutagenesis (gene mutations in specific positions that controls a specific function), and/or gene recombination (exchange of genes between multiple enzymes or variants).
- Identifying variants with optimized functions or properties and using them as a starting point for the next round of gene re-diversification.
- Repeat until a variant meets the target level of enzyme performance.
How Enzumos Labs Will Convert CO2 to Starch
Starch is a vital component in food, and animal feed, as well as an important raw material used in industrial products such as packing foam. In 2020, the global market for Starch is estimated to be 119.6 million metric tons and is projected to reach 160.3 million metric tons by 2026.
Enzumos Labs will be using the Artificial Starch Anabolic Pathway (ASAP) developed by Cai et al. for the cell-free synthesis of starch from carbon dioxide and hydrogen fuel. The photosynthesis of starch in green plants consists of 60 steps and complex regulation of the environment. The method inspired by Cai et al. reduces the process to as few as 11 core reactions. The increase in efficiency and simplicity was achieved through synthetic biology to design chemical catalysts that provide electrons or hydrogen more efficiently.
For background understanding of the reactions, there are three types of reactions involved in the synthesis of starch:
- Phosphorylation—a reaction where a phosphoryl (PO3-) group is added to an organic compound.
- C-C bond formation—a reaction where new bonds between two carbon atoms are formed.
- Isomerization—a reaction where an organic compound is rearranged into a different structure or configuration with the same chemical composition (no addition of atoms) called its isomeric form. A compound’s isomeric forms have different chemical and physical properties despite the identical chemical composition.
There are no oxidation reactions involved since the oxidation state (number of electrons gained or lost during chemical bonding) of formaldehyde (CH2O) is the same as that of starch (C6H12O5).
This process can be broken down into five main processes:
- Reduction of carbon dioxide (CO2) to methanol (CH4O)
- Conversion of CH4O into formaldehyde
- Conversion of Formaldehyde into ᴅ-glyceraldehyde-3-phosphate
- Conversion of DHAP and GAP to G-6-P
- Conversion of G-6-P to Starch
To ensure optimized conditions for the initial CO2 hydrogenation step, we propose two reaction units: the chemical reaction unit (no enzymes) and the enzymatic reaction unit. The high concentrations of formalase (fls) required to produce the right amount of formaldehyde are toxic to other enzymes, therefore, we are further dividing the enzymatic reaction unit into two steps: the formation of formaldehyde and the synthesis of starch.
Hydrogenation of CO2 to Methanol — Chemical Reaction Unit
The hydrogenation reaction—where pairs of hydrogen atoms are added to a molecule with the help of a catalyst—will take place in a tubular fixed-bed continuous-flow reactor containing a ZnO-ZrO2 catalyst.
Fixed bed reactors are the main type of catalytic reactor for large-scale chemical synthesis. The reactor will have a pressure of 20 bar and a temperature of 450 degrees Celcius, which gives a carbon dioxide conversion efficiency of 93% needed for methanol synthesis.
When the CO2 and hydrogen are fed into the reactor, they react with the fixed catalytic surface of the ZnO-ZrO2 solid solution catalyst arranged in a mesoporous structure for higher surface area and catalytic activity. The ZnO-ZrO2 catalyst with an atomic ratio of 20% Zn formed through the evaporation induced self-assembly method (an effective technique for the creation of mesoporous materials) showed the highest surface area with a relatively ordered assembly of nanoparticles with diameters of approx. 10 nm.
The hydrogenation of CO2 is a highly exothermic reaction, meaning it produces energy in the form of heat into its surroundings. Therefore, the reactor must provide thermal control over the system, and allow heat to continuously be removed from the reactor.
This reaction takes place at a rate of 0.25 g/hour/g of catalyst. It is then fed into the enzymatic unit at a concentration of 100 millimoles.
Conversion of CH4O into Formaldehyde — Enzymatic Reactor
In the enzymatic reactor, alcohol oxidase (AOX)—an enzyme derived from Pichia pastoris—removes a hydrogen pair (dehydrogenation) from methanol and combines it with oxygen to produce formaldehyde (CH2O) and hydrogen peroxide (H2O2).
The hydrogen peroxide is then decomposed by an auxiliary catalase (CAT)—an enzyme derived from Bacillus subtilis—into water and oxygen gas, which is recycled back into the reaction.
Conversion of Formaldehyde into ᴅ-glyceraldehyde-3-phosphate—Enzymatic Reactor
Then, the enzyme formolase (FLS)—derived from Pseudomonas putida—forms carbon-carbon bonds between three molecules of formaldehyde (CH2O), forming dihydroxyacetone. Formolase will be modified with increased catalytic activity catalyzed by the reaction from formaldehyde to dihydroxyacetone (DHA). The formolase enzyme has naturally low kinetic activity, requiring ~86% of the total protein dosage in its natural form to sustain the metabolic flux (flow of metabolite through a given pathway) and maintain low levels of toxic formaldehyde. Using directed evolution, the FLS enzyme is a variant of formolase with 4.7 times more optimized activity toward 5 mM (millimoles) formaldehyde and an optimized preference for dihydroxyacetone (DHA) as the main product.
Then, the dihydroxyacetone will undergo a phosphorylation reaction, where a PO3- group replaces the hydrogen atom of a hydroxyl group forming dihydroxyacetone phosphate catalyzed by dihydroxyacetone kinase (DAK) enzymes derived from Picha pastoris.
The dihydroxyacetone phosphate (DHAP) will undergo an isomerization reaction (rearranging of atoms), forming ᴅ-glyceraldehyde-3-phosphate (GAP) catalyzed by triosephosphate isomerase enzymes derived from E. coli.
Conversion of DHAP and GAP to G-6-P—Enzymatic Reactor
DHAP and GAP formed in the previous two reactions will synthesize to form ᴅ-fructose-1,6-bisphosphate (F-1,6-BP) catalyzed by fructose-bisphosphate aldolase (FBA) enzymes derived from E. coli.
Then, F-1,6-BP will undergo a dephosphorylation reaction (removal of a PO3- group) forming ᴅ-fructose-6-phosphate (F-6-P) catalyzed by fructose-bisphosphatase (FBP) enzymes derived from E. coli.
F-6-P undergoes will undergo an isomerization reaction forming ᴅ-glucose-6-phosphate (G-6-P) catalyzed by phosphoglucose isomerase (PGI) enzymes derived from E. coli.
Conversion of G-6-P to Starch—Enzymatic Reactor
G-6-P from the previous reaction will undergo an isomerization reaction, where the hydroxyl group and phosphoryl groups are switched, forming ᴅ-glucose-1-phosphate (G-1-P). This reaction is catalyzed by phosphoglucomutase (PGM) enzymes derived from Lactococcus lactis.
G-1-P will combine with ATP (adenosine triphosphate) to form ADP-glucose while producing pyrophosphate (PPI) as a byproduct. This reaction is catalyzed by ADP-glucose pyrophosphorylase (AGP) enzymes derived from E. coli.
Finally, with the help of starch synthase (SS) enzyme catalysts—derived from E. coli—ADP-glucose will lose ADP to form amylose starch (white powdery substance).
To optimize this process, three enzymes will be genetically modified using directed enzyme evolution: formolase, fructose-bisphosphatase, and ADP-glucose pyrophosphorylase.
The Enzymatic Reactor
Now that we understand the process of converting CO2 and H2 into starch, let’s break down how this works in our system.
The productivity of starch production is approximately 410 mg per liter per hour. From the balanced chemical equation, we calculate that for every 410 mg of glucose produced, 244,288.28 grams (or 0.2 tonnes) of CO2 is consumed. Therefore, approximately 5,862,918.80 grams (or 5.9 tonnes) of CO2 is consumed daily per 40 feet tall and 8 feet wide chemical reaction unit, generating 9,840 mg (or 10 grams) of amylose daily.
Advantages and Disadvantages of Cell-Free Production of Enzymes
A cell-free approach to starch production allows for a simpler, streamlined system.
- High yields
In cells, there are several pathways that take place simultaneously to maintain cell viability, therefore, they may require multiple inputs, and the input that creates the desired product may be used for other cell processes. Cell-free systems eliminate the need to maintain cell viability and are designed with only one pathway, allowing almost 100% of the input to be converted into the desired product. - Easy Optimization
Cell-free methods are much more flexible to optimizations, including adjusting enzyme levels, cofactor levels, input chemicals, temperature, and pH levels that may be impossible or destructive in cells.
There are also several challenges with cell-free enzyme utilization that need to be addressed.
- Enzyme Production Costs
Using a cell lysate approach, the added costs from the fermentation of cells are minimal because the cells would only need to be lysed into a bioreactor after the regular fermentation process. However, since our approach requires some enzymes that are genetically optimized and may require the deletion of several unnecessary cell pathways, the added costs may be higher. - Enzyme Stability
Ensuring long-term enzyme stability in low temperatures is crucial in lowering the cost and increasing the effectiveness of our enzymatic system. We will use directed enzyme evolution—an effective method based on this paper—to increase the thermostability of enzymes. - Cofactor Costs
A cell-free approach would require the cost of cofactors, including ATP, CoA, and NADH. To ensure a low cost and economic viability, these cofactors must be regenerated and reused several times. In our system, ATP will be regenerated using polyphosphate kinase (PPK) enzymes that catalyze the conversion of ADP and ATP.
Overview of Materials
Our prototype would require the following materials.
Step 1: Harnessing Electricity From Waste Heat
- PVA/CQD-based thermoelectric generator
- Heat pipes (carbon nanotube plates)
Step 2: Converting Water Into Hydrogen
Collecting Ammonia:
- Bentonite I Zeolite
- 1M NaCl solution
- 65% HNO3 solution
- Vacuum pump to isolate ammonia
Generating Hydrogen:
- Nickle-coated carbon paper (anion exchange membrane (AEM))
- NiCu/CP electrodes
- 30% KOH solution
- Vacuum pump to purify H2
Step 3: Capturing Carbon Dioxide
- Condensation chamber for water vapor condensation
- Aluminum CO2 tanks
- Cellulose acetate filter
Step 4: Producing Starch from Carbon Dioxide and Hydrogen Fuel
- Microorganism culture media
- Fermentation tank
- Centrifuge (purification of decellularized solution)
- ATP
- Starch formation reaction chambers, including gas diffusion electrode (GDE)
Financial Model
Enzumos Labs will have two primary sources of revenue. The first stream of revenue is from coal companies who will pay for our product to decrease their carbon tax, and our second stream is through selling starch to the global market which is projected to increase to 160.3 million metric tonnes by 2026.
The current cost of maintaining one acre of maize yield is $799.03. We estimate that our one-cubic meter bioreactor will have an annual starch yield equivalent to that of one-third of a hectare of maize (~0.8 acres).
Timeline
Phase 1: Executing a Pilot Study
After building the prototype and ensuring our system works in simulated environments, we will then start working on the implementation of our solution in a large coal plant with a partner company.
We plan to begin the implementation of our product in China, as it has a high demand for starch and a growing coal capacity.
Our technology will be integrated with the existing plant’s infrastructure, without impacting the existing systems. Most of the added infrastructure will be built around the exhaust of the plant, where both waste heat and carbon dioxide are readily available.
Key Directions for Research
- Optimization of energy input. We estimate that the electrooxidation of ammonia will be the largest consumer of electricity in our process, while the process of capturing carbon dioxide and producing cell-free enzymes won’t require as much.
- Optimization of genetically modified enzyme variants through directed enzyme evolution to increase the rate of carbon dioxide conversion into amylose starch.
- Optimization of the implementation plan to integrate wastewater management systems as the water and ammonia supply for hydrogen production.
- Extensive economic analysis to evaluate the timeline for the industry viability of our product to become cost-competitive against traditional agricultural starch.
- Optimization of the enzymatic bioreactor to be able to scale up the size to consume larger quantities of carbon dioxide per day.
Phase 3: Scaling Globally
Once we have completed a full check of the system in its entirety, we will be able to provide our solution to the general market, allowing anyone in the target industry to purchase and use our product.
It is at this stage that we would start to look to expand to other industries depending on the success of our solution. We have already identified nuclear as a viable clean source of energy to power our system after successful penetration into the coal industry. This would require a much larger scaled system than what will be implemented in coal plants as it would require an external source of carbon dioxide.
Projected Impact
Currently, one hectare of land can feed 5.6 people (360 million tonnes of starch) people, but with our technology, we can feed almost 19,000 people with the same amount of land (1 cubic meter bioreactor equates to the starch yield of 1/3 of a hectare).
With maize (a form of starch) accounting for 19.5% of the global calorie intake, this technology can end world hunger once and for all.
Starch is also a form of livestock feed, an industry that consumes 80% of all agricultural land. With our technology, not only are we directly feeding the population, we will decrease the amount of land and water used for livestock feed by over 90%.
If our technology were to scale to produce all of the industry’s starch, our technology would sequester 163 million metric tons of carbon dioxide annually. This is equivalent to taking 35.5 million cars off of the road every year.
This will also have a butterfly effect by reducing the impact of other environmental issues.
We can eliminate the 80% of deforestation caused by agricultural expansion, allowing the world to naturally sequester more carbon dioxide and saving hundreds of species. 15% of global greenhouse gas emissions are caused by deforestation and forest degradation, more than one-third of all land species live in forests, and 1.25 billion people rely on forests for shelter, livelihoods, water, fuel, and food security.
At Enzumos Labs, we envision a world free of climate disasters and world hunger. A future where carbon dioxide is no longer a burden, but rather a valuable resource that we can use to feed our growing population.
Hi, I’m Sophia Tang, a social entrepreneur and student researcher driven by her deep passion for tackling complex problems that disproportionately impact women. Connect with me:
