A9
Paper #174
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OPTIMIZING PHOTOSYNTHESIS IN PLANTS BY GENETICALLY
MODIFYING THE RuBisCo ENZYME
Claire Sattler, [email protected], Vidic 2:00, Jocelyn Hawk, [email protected], Vidic 2:00
Abstract-The purpose of this research is to determine the
effects of genetically modifying RuBisCo in plants on the rate
of photosynthesis.
CO2 levels are increasing in the
atmosphere due to human activity such as burning fossil fuels
and deforestation, which leads to rising global temperatures
through the greenhouse effect. One possible solution to this
problem is to increase the rate of photosynthesis in plants so
that they can take in more CO2 and convert it to oxygen and
glucose. In order to investigate this topic, past experiments
that genetically modify the RuBisCo in various types of plants
were consulted. Based on current research, it is conclusive
that genetically modifying the RuBisCo gene in plants can
optimize photosynthesis by replacing it with parts of the
RuBisCo gene in cyanobacteria. This is can be done through
a number of processes, including microinjection and through
the use of a biolistic particle delivery system, in which a
recombinant plasmid is created containing both DNA of the
plant attempting to be modified and DNA of the
cyanobacteria. Some success has been found in optimizing
photosynthesis through this process; specifically, at Cornell
University, the rate of photosynthesis in tobacco plants was
increased through this process. The genetic modification of
the RuBisCo gene in plants is a viable solution to climate
change and rising CO2 levels.
reactions. As shown in Figure 1, the Calvin Cycle begins with
Carbon fixation, where CO2 molecules react with a fivecarbon molecule, called RuBP, to form two three-carbon
molecules called 3-PGA and oxygen [11]. The CO2 molecule
breaks apart, releasing an O2 molecule as the Carbon molecule
binds with the RuBP. After the fixation of CO 2, the 3-PGA
molecules are reduced, or given an electron, by NADPH to
form six three-carbon sugars, called glyceraldehyde-3phosphate, or G3P [1]. Finally, for each cycle of the Calvin
Cycle, one of the G3P molecules are reserved to make
glucose, as shown by the arrow breaking apart from the cycle
in Figure 1, while five are recycled to form a new RuBP and
start another cycle [1]. Because of this, it takes two cycles of
the Calvin Cycle to form one six-carboned molecule of
glucose, making it less efficient than light-dependent
photosynthesis, that only takes one chemical reaction.
However, the Calvin Cycle is still important to removing CO 2
from the air because it allows plants to continue to
photosynthesize even when light energy is not available.
Without it, plants would not be able to photosynthesize during
the night, and the amount of CO2 converted to oxygen and
glucose would be greatly reduced.
Key Words- cyanobacteria, GMO, nuclear transformation,
photosynthesis, RuBisCo,
THE RuBisCo GENE AND ITS ROLE IN
PHTOSYNTHESIS
The Calvin Cycle
Photosynthesis can take place in two different ways,
light dependent reactions, also known as photophase, and
light-independent reactions, also known as the Calvin Cycle
[1]. The light-dependent reactions use energy directly from
the sun and take place in the thylakoid membrane, while the
Calvin Cycle uses energy from ATP and NADPH particles
and takes place within the chloroplasts, in the stroma [1]. The
Calvin Cycle is catalyzed by the enzyme, RuBisCo. A
catalyst is an enzyme responsible for speeding up chemical
FIGURE 1 [2]
Diagram of the Calvin Cycle
Variations in RuBisCo
University of Pittsburgh, Swanson School of Engineering
Submission date: 31.03.2017
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Claire Sattler
Jocelyn Hawk
D-Ribulose-1,5-Biphosphate
Carboxylase-Ogenase,
more commonly referred to as RuBisCo, is a complex enzyme
that plays a vital role in the Calvin Cycle. Carbon fixation, or
the combination of RuBP with CO2, is catalyzed by RuBisCo
[2]. This is done by RuBisCo’s active site binding to both an
RuBP molecule and a CO2 molecule, providing an area for the
chemical reaction to occur that binds them together [2].
Along with carbon fixation, however, RuBisCo also catalyzes
a process called photorespiration. It does this by sometimes
attaching an O2 molecule to its active site rather than a CO 2
molecule and combining it with an already fixed carbon
molecule, releasing CO2 as a product rather than glucose [3].
Because RuBisCo randomly attaches to whichever molecule
is closest to it, whether it be O2 or CO2, it is an inefficient
catalyst for carbon fixation.
Rubisco is made up of two parts, a large subunit and a
small subunit [2]. Its active site is arranged around a
magnesium ion which connects to a sugar molecule, three
amino acids, lysine, and carbon dioxide molecules [4]. The
carbon dioxide molecules attach to the RuBisCo enzymes and
act as an activator [4]. Activators are molecules that adjust
the shape of an enzyme to increase its activity [5]. Another
activator of RuBisCo is a molecule called RuBisCo Activase.
RuBisCo Activase converts RuBisCo from its inactive form
to its active state, which is necessary for RuBisCo to perform
its job of catalyzing carbon fixation [6]. RuBisCo Activase is
more fragile than RuBisCo itself, and can become easily
denatured, or made unfunctional, when subject to high
temperatures or high concentrations of CO2 [6]. Because of
this, rising temperatures and CO2 levels can dangerously slow
down the rate of photosynthesis. However, RuBisCo
Activase’s sensitivity to high concentrations of CO2 makes
optimizing RuBisCo more complex than simply increasing
the number of CO2 molecules around it. In most plants that
contain chloroplasts and are known as green plants, RuBisCo
is formed by two genes: rbcL, which is located in the
chloroplast genome and codes for the large subunit, and rbcS,
which is located in the nuclear genome and codes for the small
subunit [2]. Majority of common crops such as rice, tobacco,
and grain are considered green plants, and contain this form
of RuBisCo. One reason that genetic modification of the
RuBisCo gene is problematic in common crops is that the two
parts of the enzyme are coded for in different parts of the cell.
Unlike crops like tobacco, rice, and grain, cyanobacteria
is a prokaryotic organism and considered red algae, rather
than green. In cyanobacteria, RuBisCo differs from that of
most plants in that it is coded not only by the rbcL and rbcS
genes, but also by an assembly chaperone, called rbcX [7].
RbcX aids in the protein folding of RuBisCo, by assuring that
the protein chains coded by rbcL and rbcS do not fold into
nonfunctional structures [8]. Furthermore, both the rbcL and
rbcS gene are located in the chloroplast of the bacteria cell
[7]. In addition to the rbcX gene, cyanobacteria cells also
contain organelles called carboxysomes [7]. Carboxysomes
encapsulate the RuBisCo enzyme and concentrate CO2 around
it, so that RuBisCo is more likely to attach to CO2 molecules
than O2 molecules. Carboxysomes do this through the use of
carbonic anhydrases, which are enzymes that produce CO 2
from bicarbonate molecules [9]. Carboxysomes are formed
by a shell made up of thousands of protein sub-units, and are
filled with RuBisCo and carbonic anhydrase, as shown in
Figure 2 [9]. Scattered throughout the protein shell are pores
that bicarbonate molecules can diffuse through for the
carbonate anhydrase to convert to CO2 [9]. The presence of
the rbcX gene and carboxysomes are some of the desirable
traits that scientists are currently attempting to implement into
the DNA of crops in order to optimize photosynthesis in green
plants.
FIGURE 2 [10]
Diagram of a carboxysome, containing RuBisCo and
carbonic anhydrase
RISING CO2 LEVELS AND HOW THEY
AFFECT THE ENVIRONMENT
FIGURE 3 [11]
Graph demonstrating the increase in CO2 levels over
time
Over time, human activities, such as the burning of oil,
gas, and coal, have led to the buildup of greenhouse gases
within the troposphere, the lowest layer of the atmosphere.
Greenhouse gases are gases that trap heat in the atmosphere,
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such as CO2, the most potent greenhouse gas in our
troposphere [12]. CO2 has the ability to absorb and then give
off infrared radiation causing the CO2 molecules to vibrate.
This results in the air around the molecules to warm, and then
release heat in all directions, including towards the surface of
the Earth [13]. CO2, along with other greenhouse gases, exists
naturally within environmental processes. Plants absorb CO2
during photosynthesis while animals release it through
cellular respiration [13]. However, humans have increased
CO2 levels exponentially through the burning of fossil fuels
[14]. Some of the ways through which fossil fuel emissions
enter the atmosphere include transportation, heating and
cooling, deforestation, and fires; these emissions negatively
affect the environment and in turn, society [14].
CO2 causing its pH level to decrease; this is referred to as
ocean acidification. The process begins when CO2 dissolves
in the ocean and creates carbonic acid, which increases the
acidity of water [15]. “Since 1750, the pH of the ocean’s
surface has dropped by 0.1, a 30 percent change in acidity
[15].” This can negatively affect the environment in a number
of ways. The carbonic acid reacts with the carbonate ions in
the ocean to create bicarbonate. Bicarbonate itself does not
poorly affect the aquatic ecosystem, however the decrease in
available calcium carbonate does. Shelled organisms use
calcium carbonate in order to build and strengthen their shells
[15]. As a result, these shells end up being much weaker and
more fragile. The figure below shows the effect that lower pH
levels have on calcium carbonate shells over time. Shelled
organisms make up a large portion of the primary and
secondary consumers in the aquatic food web [18]. By
altering the population of any organism in the aquatic food
chain, a ripple effect is created, altering the population of any
other organism that is hunted by or feeds on this organism
[19].
Changes in Climate
Increasing the levels of greenhouse gases has harmful
effects on the quality of the environment on Earth. “Land,
plants and the ocean have taken up about 55% of the extra
carbon people have put into the atmosphere while about 45%
has stayed in the atmosphere [15].” Within the atmosphere,
CO2 contributes to the greenhouse effect, which traps in heat
and, as a result, raises global temperatures. The increase in
global temperatures affects ecosystems on Earth, each of
which has become accustomed to specific characteristics [16].
For example, the increase in temperature has melted polar ice
caps that polar bears and other animals depend on for habitat
[16]. The increase in temperature has also lead to an increase
in the frequency of lightning [17]. David Romps, a study
author at the University of Berkley California, studied the
effects of increased temperature on lightning while studying
atmospheric dynamics [17]. Specifically, he was researching
whether or not atmospheric characteristics could predict how
much lightning would strike in relation to the changes in
temperature. “Running the data, the team found that lightning
would be expected to increase by about 12 percent per degree
Celsius of warming (give or take 5 percent), with about a 50
percent rise over the 21st century [17].” Higher temperatures
cause an increase in water vapor in the atmosphere, which
causes the increase in amount of lightning. More lightning can
also make global warming worse because lightning strikes
produce the greenhouse gas ozone [17]. The increase of the
gas ozone in the atmosphere intensifies the greenhouse effect
already caused by CO2, increasing global temperatures and its
negative effects exponentially.
FIGURE 4 [15]
Effect of Ocean Acidification on shells
The effects of CO2 create issues that have become worse
as humans burn more fossil fuels. These issues negatively
affect Earth’s ecosystem and society by rapidly changing the
natural ecosystems that exist on Earth. Optimizing
photosynthesis by genetically modifying RuBisCo can
alleviate these negative effects by decreasing the amount of
CO2 in the atmosphere.
THE GENETIC MODIFICATION OF
RUBISCO IN GREEN PLANTS USING
CYANOBACTERIA
Effect on Ocean
The ocean is also greatly affected by the increase in CO2
in the atmosphere. With the increase in temperature, snow and
ice caps have melted, resulting in ocean levels rising about six
to eight inches in the last 100 years [15]. A rise in sea level
causes devastating results as it causes wet land flooding and
destructive erosion when the water reaches further inland
[15]. Along with this, the ocean absorbs a large portion of the
Recombinant DNA and Plasmids
Recombinant DNA, or rDNA, is created by combining
two or more different strands of DNA [20]. In the case of
optimizing RuBisCo, scientists aim to combine the DNA of
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Jocelyn Hawk
the organism whose RuBisCo they wish to optimize with that
of cyanobacteria, who’s DNA contains rbcX and codes for
carboxysomes [21]. Recombinant DNA is created by slicing
pieces of DNA using restriction enzymes [20]. Restriction
enzymes work by wrapping around sections of DNA that
match the shape of its active site and breaking these sections
off [20]. After being sliced, the ends of the DNA strands are
single stranded, with one 3’ (made up of three carbon atoms)
strand and one 5’ (made up of five carbon atoms) strand [20].
These ends are also called sticky ends because they attach, or
stick, to the sticky ends of other DNA strands [20]. These
DNA fragments are then ligated, or bound together, by
connecting the single strands together at the primer sites, as
shown in Figure 3, to make a complete, double-stranded
sequence of DNA [20].
Using a Biolistic Particle Deliver System to genetically
modify RuBisCo
Biolistics, also known as particle bombardment, is a
technology used to insert foreign or recombinant DNA into
plant cells in order to genetically modify them [23]. In order
to genetically modifiy RuBisCo, a recombinant plasmid is
formed by deleting the rbcL gene from the target cell and
replacing it with the rbcL gene from cyanobacteria [24]. This
plasmid is then inserted into the chloroplasts of the target cell
through the use of a biolistic particle delivery system, also
called a gene gun [25].
FIGURE 4 [26]
Diagram of biolistic particle delivery system
Gene guns use DNA coated microparticles to deliver
foreign DNA into the target cell [23]. Gold particles are
coated with recombinant plasmids made up of DNA
fragments from both the target cell and cyanobacteria. These
coated particles are then loaded into plastic cartridges, as
shown in Figure 4, and placed in a vacuum chamber [26]. The
cartridges are ejected from the gene gun using a high pressure
gas, usually helium, to propel them forward with a force great
enough to penetrate the plant cell walls [23]. This process is
not the most precise. The particles are targeted towards many
cells of the targeted plant, and only some of the cells will
receive the modified gene [23]. Gene guns cost around
$17,000, and their bullets, the gold microparticles, cost
around $600 [23]. They were invented in the 1980s by
researchers at Cornell University [23].
FIGURE 3 [21]
Diagram of plasmid
A plasmid is a circular ring of double-stranded DNA that
is able to independently replicate [22]. Plasmids naturally
exist in many bacteria cells, but are also artificially
constructed by scientists for cloning and genetic modification
[22]. Artificial plasmids can serve as a vector, which is a
DNA molecule used to transport foreign DNA into a cell [20].
Plasmids consist of a DNA sequence from the cell being
genetically modified, also called the target cell, that initiates
the replication of the plasmid, called the origin of replication,
as marked by the blue square in Figure 3 [23]. In order to
insert genes that code for favorable traits, such as genes from
cyanobacteria that code for the rbcX gene, into a plasmid,
restriction enzymes cut a section of the plasmid to be replaced
out. The cut ends of the plasmid consist of single stranded
DNA and are called the restriction sites [22]. These
restriction sites are where the sticky ends of foreign DNA
ligate, or connect, to the plasmid [22]. Once ligated, the
plasmid is complete and can be inserted into a target cell.
Using Microinjection to genetically modify RuBisCo
FIGURE 5 [27]
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Jocelyn Hawk
focus of key global issues: the basis for feeding an additional
2-3 billion mouths, to drive forward an economy currently
trading on past sunlight, and maintain biodiversity in the face
of climate change.’[30].”
Diagram of Microinjection
Microinjection is another process used to genetically
modify plant cells. It is much older than biolistics, first being
used in the early twentieth century, and becoming more
commonly used in the 1970s [25]. There are two different
systems of microinjection: a constant flow system and a
pulsed flow system [25]. To genetically modify RuBisCo
using a constant flow system, a solution containing
recombinant plasmids is injected into the nucleus of the target
using a glass micropipette [21]. This system is not very
precise; it is difficult to control the amount of solution being
added to the target cell and where the pipette is being placed,
often causing damage to the target cell [25]. It is, however,
inexpensive, with constant flow microinjection systems
ranging from $100-$500 [25]. A pulsed flow system allows
greater control over how much solution is added and needle
placement. Because of this, less damage is usually caused to
the target cell, and a pulsed flow system is more efficient [28].
The pulsed flow system differs from the constant flow system
in that the solution can be ejected in short bursts using
pressurized gas, allowing specification of the volume of
solution being ejected [28]. Pulsed flow systems are,
however, more expensive than constant flow systems [28].
Increase in Food Production
In parts of the world, especially in central Africa, food
shortages constantly threaten the stability of the population
[31]. For example, in the Republic of Chad, there was a rapid
spike in population due to the addition of over 370,000
refugees. Their food production was already unable to feed
the native population prior to the addition of refugees. The
increase in population paired with the stagnant production of
food has resulted in increased pressure on local food sources
and starvation. Over 4,447,000 people in Chad are estimated
to be in need of food assistance [31]. Having the technology
of genetically modified RuBisCo available to countries like
Chad that suffer from low food production would increase
crop yield in these countries. In turn, this would help combat
the widespread hunger that currently is affecting many
countries around the world.
Effect of CO2 Concentrations on Human Health
THE SIGNIFICANCE OF MORE
EFFICIENT PHOTOSYNTHESIS TO
SOCIETY
Through genetically modifying RuBisCo, scientists
have been able to make significant progress in optimizing
photosynthesis. Optimizing photosynthesis, specifically the
step involving carbon fixation, allows plants to take in more
carbon dioxide from the atmosphere [29]. Enabling plants to
do this results in numerous positive effects to plant growth
and the environment, consequently benefitting society as a
whole. CO2 is a limiting factor in terms of the growth of
plants. In a study done at the University of Illinois UrbanaChampaign, Justin McGrath and his team performed a
computer model to simulate how the addition of the
cyanobacteria genes would affect the growth and
photosynthesis efficiency of plants [29]. The team found that
this modification of plants could increase photosynthesis by
60 percent. Because CO2 provides fuel for the plant through
photosynthesis, increasing the efficiency also increases the
rate at which the plants grow. The same team simulated the
growth of two plants under the same conditions (temperature,
precipitation, sunlight etc.), however one had the genetically
modified RuBisCo and one did not. The genetically modified
plant grew to be 40 percent taller than the one that had no
genetic modification [29]. Faster crop growth leads to an
overall increase in total crop yield and food production in
general. “Professor Howard Griffiths from the Department of
Plant Sciences said: ‘Plants really matter, and for the next
generation, plant and microbial productivity will become the
FIGURE 7 [32]
Chemical equation for photosynthesis
Along with increasing food production, altering the
RuBisCo in plants also decreases the massive amounts of CO2
that exist in our atmosphere. As shown in Figure 7,
photosynthesis converts CO2 and water into glucose and
oxygen [32]. By increasing the speed and frequency through
which plants undergo photosynthesis, plants would convert
more CO2 as a result, reducing the number of molecules in the
atmosphere.
Various health issues have been linked to human
exposure to high CO2 concentrations [33]. A study done by
the Harvard School of Public Health observed the effects of
being exposed to different concentrations of CO2 [33]. The
team chose concentrations that match the current
concentration of CO2 in the atmosphere and the projected
concentrations over the next century. As shown in Figure 8,
there is an inverse correlation between the concentration of
CO2 and various cognitive abilities-basic activity, crisis
response, information usage and strategy [33]. The team
studied these cognitive abilities at CO2 concentrations from
500ppm to 1500ppm. The current concentration is 400ppm,
however indoor concentrations can be anywhere from
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Claire Sattler
Jocelyn Hawk
200ppm to 400ppm higher than outdoor concentrations
because of lack of ventilation [33]. “In surveys of elementary
school classrooms in California and Texas, average CO2
concentrations were above 1,000 ppm, a substantial
proportion exceeded 2,000 ppm, and in 21% of Texas
classrooms peak CO2 concentration exceeded 3,000 ppm
[33].” This means that as CO2 concentrations increase in the
atmosphere, they increase even more indoors, where people
spend most of their day. CO2 projections estimate that if the
world continues to burn fossil fuels at its current rate then by
the year 2100, average outdoor concentrations will rise to 910
ppm [33]. As shown on the graphs, cognitive abilities show a
clear decrease when concentrations reach this level. Altering
the RuBisCo gene in plants can help to decrease atmospheric
CO2 levels, and therefore keep both indoor and outdoor
concentrations from reaching dangerous levels.
graph below shows the correlation between the increase in
CO2 and the decrease in O2 [34]. The decrease in O2 is directly
proportional to the increase in CO2. Currently the atmosphere
is made up of about 20% oxygen [36]. As oxygen levels
decrease, various health issues begin to affect humans.
Between 15 and 16%, humans begin to experience impaired
thinking and attention. It also begins to affect humans
physiologically too with an increase in pulse and breathing
rate paired with a decrease in coordination [36]. A decrease
in oxygen also makes it difficult for animals to undergo
respiration. Through respiration, animals convert oxygen and
glucose into carbon dioxide, energy and water [32]. Similar
to plants, less oxygen results in a decrease in the ability for
animals to grow due to a decrease in energy. Genetically
modifying RuBisCo can help this by increasing the
concentration of O2 by decreasing the CO2 in the atmosphere.
FIGURE 9 [34]
Correlation between CO2 levels and O2 levels
SUSTAINABILITY OF GENETIC
ENGINEERING
Although research done on genetic engineering as a
means to lower CO2 is relatively new, the results that have
come from this research make it apparent that the genetic of
modification of RuBisCo is an environmentally sustainable
technology. Through processes like biolistic particle delivery
systems and microinjection, the rate of photosynthesis in
plants is able to be increased, lowering CO2 levels in the
atmosphere, benefitting the environment. However, along
with the environmental sustainability of RuBisCo, its
economic and social sustainability must also be considered in
order to confirm whether or not genetic engineering is a
technology worth pursuing.
FIGURE 8 [33]
Effect of CO2 levels on cognitive ability
Increasing Atmospheric Oxygen
The optimization of photosynthesis would not only work
towards decreasing the amount of CO2 in the atmosphere, but
it would also increase the amount of atmospheric oxygen [32].
When anthropogenic carbon, C, is released into the
atmosphere, it attaches to the atmospheric oxygen, O2, and
forms the greenhouse gas carbon dioxide. This combination
is what causes global warming, climate change, ocean
acidification and the other issues discussed previously. The
Economic Sustainability of Genetic Engineering
Genetic engineering, such as the genetic modification of
RuBisCo, is a lengthy and expensive process. Based on a
study done in 2011, the total amount of money spent on
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Jocelyn Hawk
discovering, developing, and authorizing genetically
engineered plants was $136 million [35]. Along with being
expensive, genetic engineering is a long process, with the
average time from the initiation of a project to create a GMO
to commercial launch being 13 years [35]. While these
statistics make genetic modification of plants seem extremely
economically unsustainable, much of the price and time put
into GMOs are due to government enforced regulatory testing
and registration, rather than the actual development of the
organism. 26% of the costs of genetic engineering are due to
government testing and registration, and registration is the
longest phase of GMO development, lasting on average 5.5
years [35]. The reasons for these regulations are possible
health and environmental risks, such as loss of biodiversity or
allergenicity of transgenes[36]. However, no unanticipated
risks have been confirmed, and those that have are certainly
manageable. While some regulation should exist for any new
technology in order to protect the safety of the people, some
believe that GMOs are overregulated, and their risks are
overexaggerated, while their benefits are underexaggerated
[36].
Although expensive, as GMOs become more
normalized, these time and cost restraints posed by the
government may be reduced [36].
Furthermore, the
introduction of GMOs into certain countries has actually
benefitted the economy due to higher crop yields. For
example, one study in India found that genetically engineered
cotton created an 82% increase in incomes for small-farm
households [36]. GMOs may require a significant amount of
money to develop, but can also positively affect the economy
in countries like India. Although genetic engineering can be
expensive and time-consuming, the costs of it, especially as
government regulation is relaxed, are well worth the benefits
of a healthier environment.
THE EFFECTIVENESS OF ENGINEERING
THE RUBISCO ENZYME TO INCREASE
THE RATE OF PHOTOSYNTHESIS
Limitations of Genetically Modifying RuBisCo
The continuing problem that exists with genetic
modification of crops in general is the lack of research on the
future of GMOs and their effect on humans [38]. The first
GMO did not get FDA approval until 1982, meaning they
have only been around for the last 35 years [39]. Scientists are
relatively unaware of the effects of growing and consuming
GMOs could have on humans over longer periods of time.
The genetic modification of RuBisCo is a relatively new
GMO and would require more research before it can be
implemented. It has yet to be tested in a larger scale setting
[39]. It is also very expensive to perform the genetic
modification and requires expensive technology [23].
Although the RuBisCo GMO has the potential to improve
pertinent societal and environmental issues, it will need to be
researched further before it can be widely used.
Genetic Modification of RuBisCo is Worth
Pursuing Despite Limitations
By creating a more efficient RuBisCo enzyme and
ultimately optimizing photosynthesis in plants, pertinent
issues involving the global atmosphere, economy and health
can be addressed and improved. Through the increase in plant
growth and decrease in atmospheric CO2, food production
would increase, the effects of climate change would decrease
and health issues related to amounts of CO2 and O2 in the
environment would decrease. Other methods of decreasing
atmospheric CO2, such as renewable energy sources, can be
effective and even less expensive; however, they do not
provide the other benefits that the modified RuBisCo enzyme
does, such as increasing plant growth and food production
[38]. Therefore, the genetic modification of RuBisCo has the
potential to be one of the best methods of combatting climate
change because of the widespread effects optimizing
photosynthesis has on not only CO2 and oxygen levels, as well
as food production.
Social Sustainability of Genetic Engineering to lower
CO2
Social sustainability is the function of a society to exist
at a state of well-being. The genetic modification of RuBisCo
to increase the rate of photosynthesis has a positive impact on
social sustainability due to its health benefits. Some studies
have shown that high CO2 levels in the atmosphere negatively
and directly affect human cognition, making it harder for the
brain to operate. In addition, pollution can cause lung
problems, such as asthma [37]. Along with high CO2 levels,
low amounts of oxygen have also been proven to cause health
risks, such as increased susceptibility to conditions like brain
hypoxia, pneumonia, and bronchitis [37]. Using the genetic
modification of RuBisCo to reduce CO2 levels and increase
oxygen levels would have positive benefits to public health
and the well-being of society, thus proving it to be socially
sustainable.
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Jocelyn Hawk
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ACKNOWLEDGEMENTS
Thank you to our good friend, Emily Utendorf, for
providing moral support during the writing of this paper.
Also, thank you to Daniel Zunino for discussing our research
with us.
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