Genetically Engineered Plants To Reduce Atmospheric Methane and Global Warming

Guest Post by Neil Farbstein
Neil Farbstein contact info; [email protected]

Methane in the atmosphere is a very potent greenhouse gas. Over a 20-year period, methane traps 84 times more heat per mass unit than carbon dioxide. There is a distinct possibility that large increases in future methane may lead to surface warming that increases nonlinearly with the methane concentration. The concentration of methane in the atmosphere has more than doubled, since the start of the Industrial Revolution, and approximately a fifth of the warming the planet has experienced can be attributed to the gas.

According to Wikipedia; Multiple independently produced instrumental datasets confirm that the 2009–2018 decade was 0.93°C
warmer than the 1850–1900 baseline period. A reasonable linear first approximation would predict that halving total atmospheric methane will reduce global average temperatures by 0.186 °C.

The biggest natural source of methane natural emissions is wetlands. Bacteria that live under low oxygen conditions in waterlogged wetland soils produce methane. Approximately 30% of atmospheric methane comes from that source.

The arctic permafrost and methane ice clathrates under the oceans contain huge amounts of methane.

Climate scientists are worried that as global air temperatures rise it will cause methane ice to vaporize, increasing the release of heat-trapping methane into the air that will in turn cause more methane ice to vaporize and release even more methane in a feedback loop that results in out of control greenhouse warming. The endpoint of that process might be a Venus syndrome scenario that destroys all life on earth but it is more likely that a new equilibrium will come about where temperatures won’t exceed the hottest temperatures of the cretaceous era when dinosaurs lived in steaming hot swamps at the north pole and the equatorial regions were vast deserts. Of course, that type of climate will be disastrous for the human race since desertification will cut the food supply and make vast stretches of land too hot to live in.

“Researchers from Stockholm University on the icebreaker Oden in the Arctic Ocean that “vast methane plumes” were rising from the ocean floor probably due to a tongue of warmer Atlantic water that is penetrating into the Arctic”

The picture below shows a methane flare from methane that bubbled up under the ice on a frozen arctic lake.

Cows, pigs and other ruminants have methanogenic bacteria in their stomachs that produce methane in their burps and farts. The manure they excrete contains those same bacteria and goes on producing even more of the greenhouse gas. There are 1.4 billion cattle in the world, and billions of other methane producing ruminant animals. The United Nations report, “Livestock’s Long Shadow” claimed livestock are responsible for 18% of Green House Gas emissions. Total agricultural methane releases come to 188 million tons. Rice paddies are another big source of methane. The flooded swamp-like conditions have low oxygen levels that methane-producing bacteria thrive in. Methane from rice contributes around 1.5 percent of total global greenhouse gas emissions. It is not necessary to grow rice in flooded fields and there is a movement to grow rice under dry conditions that drastically reduce methane but that also lowers rice yield.

As it becomes clear that the effects of global warming are causing more and more deaths and costly destruction of the world’s infrastructure, some environmentalists are proposing radical solutions like restricting cattle farming and the sale of meat. However, there is work on finding feed additives that reduce the amount of methane generated by bacteria in the stomachs of ruminants. A number of compounds from seaweed were found to reduce the amounts of methane they emit, but the bacteria mutate and adapt to the seaweed compounds and they lose their effectiveness. There are seaweed compounds in tests now that might keep their effectiveness over time, but there are no guarantees that strategy will work. The puffy, pink seaweed known as Asparagopsis taxiformis, reduces methane by 99% when its fed to cows.

Neil Farbstein the President of the Clean Energy Research Foundation Inc. has figured out a way of reducing global methane that uses naturally occurring methane mono-oxygenase (MMO) enzymes.

Many types of bacteria make a variety of methane mono-oxidases that oxidize methane to methanol which has 84 times less overall global warming potential. About half of the methane bubbling up from methane ice at the bottom of the oceans is absorbed and metabolized by bacteria that contain MMO and it never reaches the surface. The amount of methane that does enter the atmosphere from vaporizing methane ice is huge and increasing, since its release heats the atmosphere and the water below. Warming waters of oceans and arctic lakes containing methane ice causes it to melt and release even more methane in a vicious cycle.

Mr. Farbstein’s plan to reduce methane caused global warming is to genetically modify land plants to synthesize methane monooxygenase (MMO) and seed large patches of land with them. Seaweed and unicellular algae can also be genetically modified to make MMO but their growth in the oceans cannot be controlled. Environmentalists believe that some methane is necessary to keep the planet warm enough to avoid ice ages. Thus it is necessary to control proliferation of GMO plants with added MMO by keeping them on the land.

If food and biofuel crops, are modified, they can be harvested or otherwise destroyed if a point is reached where methane levels have gone down too much, resulting in too much global cooling. We wont have to worry about that for a long time though.

One solution will be adding suicide genes to GMO plants in addition to either soluble methane monoxygenase (MMO). Suicide vectors have been studied as a method of eliminating cell therapy cell introduced into patients, If those cells mutate and become cancerous or induce graft vs. host disease it is advantageous to remove them. The suicide vectors are genes that encode enzymes that turn
harmless substances into toxins. Patients can be given substances such as the antifungal drug 5-fluorocytosine, which causes destruction of implanted cells transformed to make the enzyme cytosine deaminase, which converts 5-fluorocytosine into cytotoxic 5-fluorouracil.

Many commercial GMO crops are transformed with an enzyme that neutralizes the herbicide, glyphosate. Those crops that have the resistance gene added to their genome can grow in the presence of glyphosate while weeds that grow alongside them have no resistance and are killed. Genetic engineering can also accomplish the reverse by inserting genes like those used in transgenic cell therapy that turn nontoxic substances into toxins that kill rogue cells. It is probably impractical to transform crops with cytosine deaminase since 5-fluorocytosine is currently very expensive. The very cheapest pills sold in the UK cost $2 each. That might change in the future if the expensive four-step manufacturing process is replaced with a much simpler one-step process that directly fluorinates cytosine with gaseous fluorine.

GMO plants that have the methane mono-oxygenase gene implanted into their genomes can also be transformed with the cytosine deaminase suicide gene. If it is determined that those plants are removing too much methane from the air and causing too much cooling, 5-fluorocytosine can be sprayed to destroy them and remove them from the environment. As discussed above, 5-fluorocytosine might be impractical since it is too expensive. There is no doubt that other genes that confer weaknesses to plants can be inserted into GMO plants’ genomes to remove them from the environment if desired. And those transgenic enzymes can activate cheaper and environmentally harmless chemicals that also destroy the GMO plants. Strains of GMO plants that depend on externally supplied nutrients can be kept from escaping plots where they are grown also.

The MMO gene and its trait of oxidizing methane to methanol is nonessential to the survival of plants transformed with it. The amount of methane in the air is so low that it will not serve as a nutritional source that increases reproductive fitness. Thus, it is certain that GMO plants with the MMO gene have no evolutionary advantage and those plants will naturally lose that trait over a number of generations.

Adding genes like cytosine deaminase might be overkill and unnecessary.

Two forms of MMO have been found: soluble and particulate. The most characterized forms of soluble (sMMO) contains three protein components: hydroxylase, the β unit, and the reductase all of which are necessary for effective substrate hydroxylation and NADH oxidation. The membrane bound enzyme has 2 subunits and loses its activity when its is removed from the membrane. Both types have been
cloned and can be transfected into higher plants and cyanobacteria. sMMO is active at lower levels of copper in the environment. sMMO has a much higher enzyme activity and turnover than pMMO. A transcriptional activator, mmoR, and the chaperone protein, mmoG are required for sMMO expression and copper chelating protein methanobactin, genes that are encoded by the methanobactin operon might also necessary to create actively methane oxidizing GMO. Modern genetic engineering technology is capable of fully expressing those genes together in bacteria and plants.

The most productive method of engineering plants to express proteins is by inserting the genes into the genomes of chloroplasts, producing up to 10% of total plant proteins. Other relevant methods will be nuclear expressed genes that make soluble methane mono-oxidase in the leaf cytoplasm or in membrane vesicles.

The list of GMO genetically modified plants is long and includes, grasses such as corn, wheat, alfalfa, creeping bentgrass and rice and also trees such as poplars and pines. Methane releases by cows, sheep and other ruminants can be dealt with by surrounding them with fields of GMO feed grasses and crops that metabolize and remove methane from their environment. Some methane oxidases in their feed might also be active in their stomachs and further neutralize methane at its’ source.

Grasses that grow near swamps and wetlands might also be modified to oxidize methane. Lakes and swamps are among the biggest generators of methane. That includes lakes in the arctic where rising temperatures are releasing huge amounts of methane that was trapped in methane clathrate ice. Also as they warm up, biological processes where methanogenic bacteria feed on decomposing plants and
animals contribute approximately 50% to the methane problem.

The azolla plant is a primitive fern that is found naturally in freshwater ditches, ponds, lakes and sluggish rivers of warm temperate and tropical regions. It floats on the water sometimes completely covering those bodies of water. It has a characteristic that makes it particularly easy to transform for the purposes of reducing worldwide methane levels. Azolla is a symbiotic organism that depends on the cyanobacterium Anabaena. Azolla provides an enclosed environment for Anabaena within its leaves.

In return, Anabaena sequesters nitrogen directly from the atmosphere which supports the Azolla plant’s growth, freeing it from the soil for its’ nitrogen source.

It is much easier and cheaper to transform bacteria than green plants. Thus, instead of transforming azolla with MMO genes, it is possible to transform the anabaena bacterium that lives inside it and to then infect azolla with the GMO cyanobacterium. Anabaena azoillae- the species that grows inside azolla leaves is completely dependent upon it and it cannot grow by itself. It is vertically transmitted from generation to generation meaning that azolla containing the GMO cyanobacterium reproduces itself without externally supplied anabaena. Thus, GMO anabaena azoillae cannot escape and grow by itself in fresh waterways or the ocean.

And azolla grows where much of the worlds methane is generated, on lakes, marshes, swamps and rice paddies. Azolla is grown in rice paddies as a companion plant, because it fixes nitrogen from the air making it unnecessary to add artificial fertilizers. Rice farmers used azolla as a rice biofertilizer 1500 years ago. The earliest known written record of this practice is in a book by Jia Ssu Hsieh in 540 A.D

“The Art of Feeding the People.” In the Ming dynasty in the early 17th century, azolla’s use as a green compost was recorded in numerous local records. Azolla powered by anabaena draws down the atmospheric nitrogen that fertilizes, and provides a nitrogen-filled home for the cyanobacterium within its leaf cavities. This enables the plant to double its biomass in as little as two days free floating on water as shallow as one inch (2.4 cm). It has been measured as absorbing 32.5 tonnes of CO2/ha/yr as opposed to Dunaliella algae at 7 tons of CO2/ha/yr and trees that sequester 4 tons of CO2/ha/yr.

There are certain advantages to using genetically modified grasses, crops, trees and azolla to successfully reduce atmospheric methane levels. According to estimates by NASA, a fifth of all global warming is caused by excess methane and can be reversed. Plants with implanted genes are cheap and they reproduce themselves. They can be employed by farmers and agronomists with minimum technical skills. If they are transformed with suicide genes they can be eliminated from the landscape if that step is necessary. And natural laws of reproductive fitness ensure that populations of GMO plants with the MMO genes will gradually lose that trait over time, even if we do nothing.

Robert Jackson and his colleagues have analyzed the economics of using machines that remove methane from the atmosphere;
https://www.scientificamerican.com/article/turn-methane-into-co2-to-reduce-warming-experts-propose/
https://www.popsci.com/turning-methane-into-carbon/
The Scientific American article discusses using carbon tax credits and argues that removing methane from the air can be a profitable business that cools the planet at much lower cost than machines that remove CO2 from the air. The methane removing machines proposed by Rob Jackson would use heated zeolite catalysts but his work is theoretical. Aquatic and soil bacteria that remove methane from the environment exist now and the self reproducing characteristics of GMO plants make them even more economical.

Mr. Farbstein thinks the most practical way of reversing global warming by 1/5 of a degree Celsius will be growing plots of geographically and nutritionally restricted GMO plants and aquatic azolla farms that combine GMO methane reduction with production of large amounts of azolla for fertilizer which will also sequester CO2 in the ground. Biofuel crops including azolla can also be transformed with MMO to remove methane from the air and serve as a source of income to make the operation self-sufficient.

Neil Farbstein contact info; [email protected]