USAFA - iGEM 2024

Background

Sustainable development is a model of progress that seeks to meet the needs of the present without compromising the ability of future generations to meet their own needs. It emphasizes the balance between economic growth, environmental protection, and social equity, aiming to promote long-term solutions that foster human well-being while ensuring the health of the planet.

The United Nations' 17 Sustainable Development Goals (SDGs) are a global framework adopted by all UN Member States in 2015 as part of the 2030 Agenda for Sustainable Development. These goals are designed to address the most urgent challenges facing the world, with the aim of creating a more sustainable, equitable, and prosperous future by 2030. Bio Si-ment aims to address the following UN SDGs:

Sustainable Development Goals 9 and 11:

Goal 9: Build resilient infrastructure, promote inclusive and sustainable industrialization, and foster innovation.

Goal 11: Make cities and human settlements inclusive, safe, resilient, and sustainable.

Imagine you’re enjoying a nice morning stroll, sun warm on your skin, the breeze flowing through your hair – until bam, your foot catches on the cracked cement of the sidewalk you’re walking on. Down you stumble onto the concrete, your shoes scuffed, body sore, and pride wounded. Unfortunately, cracked cement, whether on sidewalks, roads, or buildings, is a sight we are all too familiar with, and a costly problem when these cracks pose safety risks and must be replaced. However, Bio Si-ment, or E. coli INP-sil provides an exciting alternative to address these issues.

Biocementation is known for having self-healing properties, allowing biological processes to repair microcracks in cement before large fissures are formed. When biocementation methods are applied to traditional cementitious materials, this microbial self-healing can prolong their lifespan without using costly or time-consuming interventions (Nasser, 2022).

Furthermore, global urbanization trends combined with an increasing global population continue to drive the necessity for safe, resilient cement in infrastructure use. A report published by the UN in 2018 projects that 2.5 billion more people will be living in cities by 2050 (UN News, 2018). Because cities and infrastructure are reliant on each other for growth and functionality, this expansion of cities requires an expansion of housing, transportation, and general urban infrastructure, for which cement is the primary construction material. However, total emissions from the current cement industry account for 8% of global CO₂ emissions (Andrew, 2018).

The use of E. coli INP-sil for production of biocement provides a more environmentally friendly alternative to meet the urbanization cement demand. However, because cement costs only 13 cents per kilogram to produce, economic limitations paired with strength drawbacks make Bio Si-ment or other biocementation methods unfeasible replacements for the current cement industry (Chandler, 2019). Instead, E. coli INP-sil would be best utilized in conjunction with traditional cement for microcrack repairs to prolong the lifespan of these materials. At the same time, further optimization should be pursued to enhance the economic viability and strength of biocementation methods, aiming to eventually replace conventional cement. This will enable the creation of safer, more sustainable, and resilient infrastructure and cities, fostering environmental stewardship while enhancing the quality of life for future generations.

Sustainable Development Goal 15:

Goal 15: Protect, restore, and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss.

Each year, the United Nations Convention to Combat Desertification (UNCCD) estimates that at least 100 million hectares of healthy land is lost to desertification and land degradation globally (UNCCD, 2023). Ibrahim Thiaw, executive secretary of the UNCCD, stated that land degradation is reducing the global economy by up to 17 percent, representing an economic loss of approximately 15 trillion USD annually (Reinl, 2019). Additionally, around 3.2 billion people are adversely affected by land degradation (UNEP, 2022). Addressing these challenges is vital to safeguarding the environment, ensuring social stability, and advancing economic prosperity.

After interviewing Dr. Herrick, the U.S. science representative the UNCCD, our team was able to integrate some useful information into our design process, tailoring the applications of E. coli INP-sil to combat desertification and land degradation. Dr. Herrick believes that Bio Si-ment would be most applicable in arid or hyper-arid regions, where alternative anti-desertification methods, such as planting vegetation, are less feasible. However, Bio Si-ment also has promising potential for other environments too. Disturbed soil and sand deposits are significantly prone to saltation, the most important transfer mode for wind erosion. Saltation is caused by sand or similarly sized particles becoming slightly affected by turbulent eddies and showing a parabolic trajectory superimposed by a fluctuating motion (Gromke and Burri, 2011). Simply put, it is the process causing sand to make successive short hops that results in bombarding downwind soil or sandblasting of crops.

When these soil and sand deposits are upwind of arable land, it can cause land degradation of farmland by removing topsoil and even destroy mature crops. During a discussion with Jamie Clark, a local Colorado farmer, our team learned how essential nutrient-rich topsoil is to crop growth and productivity. Mr. Clark stated that preserving topsoil on farmland would help farmers avoid the costly and resource intensive process of replacing topsoil lost to land degradation. In fact, the U.S. agricultural sector loses about $44 billion USD per year from erosion (Sulaeman and Westhoff, 2020). The biostabilization capabilities of E. coli INP-sil make it an effective option for mitigating saltation and wind erosion, especially when used in conjunction with other land preservation techniques. Primary targets of biostabilization should include soil in arid or hyper-arid regions, sand deposits, and disturbed soil caused by roadways or other infrastructure.

Impact on Other Sustainable Development Goals:

Goal 2: End hunger, achieve food security and improved nutrition, and promote sustainable agriculture.

Land degradation and desertification directly threaten food security by reducing the availability of fertile land for agriculture. The loss of 100 million hectares of healthy land annually and the economic impacts of up to $15 trillion in losses illustrate the scale of the problem. As land continues to degrade, farmers face challenges like soil erosion and the destruction of crops, making it harder to produce sufficient food. The development of E. coli INP-sil to combat desertification through biostabilization could be a vital solution, especially in arid regions where traditional methods like planting vegetation are less effective.

Utilizing E. coli INP-sil to combat desertification and halt land degradation through biostabilization would play a vital role for agriculture and food availability. By preserving topsoil and preventing wind erosion, this technology can help maintain farmland productivity, support sustainable agriculture, and ultimately contribute to ending hunger and achieving food security.

Goal 12: Ensure sustainable consumption and production patterns.

Second only to water, cement is the second most consumed material globally, playing a critical role in urbanization and infrastructure (Gagg, 2014). While Bio Si-ment may not yet be a cost-effective replacement for conventional cement, its application in microcrack repair supports sustainable production by minimizing waste and maximizing the longevity of materials. By optimizing these methods, we can create safer, more resilient infrastructure while promoting environmentally responsible consumption patterns and reducing the carbon footprint of urban development.

Goal 13: Take urgent action to combat climate change and its impacts.

The cement industry is a major contributor to climate change, producing over 3 gigatons of CO₂ annually, accounting for 8% of global carbon emissions (Chandler, 2019). This vast output significantly accelerates global warming, making it crucial to address. The use of E. coli INP-sil in biocementation presents a potential solution to reduce these emissions. By incorporating microbial self-healing properties, biocement can extend the lifespan of traditional cement, reducing the frequency of new cement production and the associated carbon emissions. Although further optimization is required before replacing conventional cement entirely, Bio Si-ment can help lower the industry's CO₂ footprint, contributing to the urgent need to combat climate change.

Sources

• Andrew, R. M. (2018). Global CO2 emissions from cement production. Earth System Science Data, 10(1), 195–217. https://doi.org/10.5194/essd-10-195-2018
• Chandler, D. L. (2019). Researchers have created emissions-free cement. (2019, September 18). World Economic Forum. https://www.weforum.org/agenda/2019/09/cement-production-country-world-third-largest-emitter/
• Gagg, C. R. (2014). Cement and concrete as an engineering material: An historic appraisal and case study analysis. Engineering Failure Analysis, 40, 114–140. https://doi.org/10.1016/j.engfailanal.2014.02.004
• Gromke, C., Burri, K. (2011). Wind Erosion. In: Gliński, J., Horabik, J., Lipiec, J. (eds) Encyclopedia of Agrophysics. Encyclopedia of Earth Sciences Series. Springer, Dordrecht. https://doi.org/10.1007/978-90-481-3585-1_235
• Nasser, A. A., Sorour, N. M., Saafan, M. A., & Abbas, R. N. (2022). Microbially-Induced-Calcite-Precipitation (MICP): A biotechnological approach to enhance the durability of concrete using Bacillus pasteurii and Bacillus sphaericus. Heliyon, 8(7), e09879. https://doi.org/10.1016/j.heliyon.2022.e09879
• Reinl, J. (2019). Desertification Costs World Economy up to 15 trillion dollars—U.N. | Inter Press Service. https://www.ipsnews.net/2019/09desertification-costs-world-economy-15-trillion-dollars-u-n/
• Sulaeman, D., & Westhoff, T. (2020). The Causes and Effects of Soil Erosion, and How to Prevent It. https://www.wri.org/insights/causes-and-effects-soil-erosion-and-how-prevent-it
• UNCCD. (2023). At least 100 million hectares of healthy land now lost each year. UNCCD. https://www.unccd.int/news-stories/press-releases/least-100-million-hectares-healthy-land-now-lost-each-year
• UNEP. (2022). Facts about the nature crisis | UNEP - UN Environment Programme. https://www.unep.org//facts-about-nature-crisis
• UN News (2018). Around 2.5 billion more people will be living in cities by 2050, projects new UN report | UN DESA | United Nations Department of Economic and Social Affairs. (n.d.). Retrieved September 27, 2024, from https://www.un.org/development/desa/en/news/population/2018-world-urbanization-prospects.html