Project Description

Introduction

Spanning late 2024 to early 2025, a particularly damaging bout of wildfires ravaged the United States, reaching into Canada. Beyond the infamous California wildfire season, this widely prevalent issue has unfortunately transcended any one particular state or country.

When researching the impacts of wildfires, NU Boston not only noted the rise in wildfire prevalence, but also themes in the way wildfires are dealt with. Present solutions, outlined below, are not eco-friendly, overtly dangerous, and retroactive in principle, only applicable once a wildfire has established itself.

Current Methods of Wildfire Suppression

Prescribed Burns

These planned and controlled burns are meant to control vegetation build-up and minimize the amount of accessible fuel for a potential wildfire. Though conducted in what is determined to be the safest weather and environmental conditions, these burns can quickly become dangerous due to unexpected winds and flying embers. These factors contribute greatly to prescribed burns turning from controlled to devastating, endangering families, community members, and firefighters. Their danger is coupled with an increase of smoke and particulates entering the air, causing air pollution for surrounding communities, limiting their access to clean air to breathe.

Aerial Water Drops

Aerial water drops involve aircraft, such as helicopters or planes, releasing large volumes of water or fire retardant over wildfires to slow their spread and reduce heat intensity. This method is often used in hard-to-reach areas or to protect critical zones while ground crews establish containment lines. Although visually dramatic and useful for temporary suppression, aerial drops are not the most effective way to fight wildfires because much of the water evaporates before reaching the flames, wind can scatter the drops unevenly, and the effects are short-lived without ground support. Ultimately, aerial operations work best as a supplement to, rather than a replacement for, ground-based firefighting efforts.

Phos-Chek

Considering the previous method's mention of the use of fire retardants in aerial drops, one common component of wildfire treatment is Phos-Check, a synthetic fire-retardant primarily composed of ammonium polyphosphates. When mixed with water, it forms a viscous solution that decreases the amount of oxygen and flammable material accessible by the flames. Furthermore, the high amounts of Phosphorus and Nitrogen in Phos-Chek allow it to form a "char barrier" if combustion does occur. This barrier acts as a chemical and physical block that prevents the further combustion of flammable material. Though effective at limiting the spread of wildfires, there are many faults with Phos-Chek that keep it far from being a perfect solution for wildfire suppression.

In a 2024 study conducted by University of Southern California, fire retardants added over 400 tons of toxic metals to the surrounding environment from the years of 2009 to 2021. Other compounds found within this product like ammonium and phosphoric compounds, have been shown to cause severe irritation to human skin and eyes when contact is made through contaminated water. Current SDS sheets state that the most recent version of Phos-Chek still "may cause long-term adverse effects to aquatic environments", indicating that environmental issues arising with the use of previous iterations of Phos-Chek have not been resolved as of 2025. Moreover, the high concentrations of Nitrogen in Phos-Chek make it a potent fertilizer that, when exposed in large enough amounts to water sources, can cause algae blooms that devastate aquatic ecological balance. For families looking to rebuild, the effects of chemicals contaminating their water supply mean that the fire may not be the sole hardship they face. Not only does it cause health issues to humans, it also upsets ecological equilibrium in aquatic environments. While this method provides immediate results in reaction to wildfires, it causes long-term issues for both human and non-human lives who have already been negatively affected by the fires themselves.

As a reactive measure, there is only so much damage control it is effective for. Because its application depends on planes, high winds and large amounts of smoke from already-burning fires significantly decreases its window of application. However, another wildfire suppression method that is proactive in nature comes at an even greater risk to the lives of firefighters, who are responsible for implementing the following strategy.

Question

While current solutions can be beneficial to containing wildfires, their negative impacts diminish their effectiveness and expose communities and environments to unnecessary risks. Acknowledging the need for a new solution, NU Boston has set out to pioneer a new strategy on the battlefield against wildfires that decreases the environmental and societal impact wildfires have on communities and ecosystems

The motivation for a wildfire suppression method that is proactive in nature and eco-friendly drove us to our research question: What product can we develop that is safe for anyone to use and can allow firefighters to take action against wildfires before they break out?

Project Design

After a year-long effort to come up with an answer to this question, NU Boston is happy to present FloraGuard, a new bio-based flame retardant that is both safe for the environment and can be deployed well before the threat of wildfire is imminent. FloraGuard is a protein-based flame retardant that uses a cellulose binding domain to attach biological flame retardant compounds to the exteriors and interiors of plants. FloraGuard is unique in that we developed many iterations of our protein complex, each with a different type of bio-flame retardant protein, to fit the needs and restrictions of different communities and environments.

Previous iGEM Teams

Initially, we took inspiration from the EDC-Seas project developed by the 2023 IFB-GDansk iGEM team. In their project, they were able to attach multiple enzymes to a cellulosome-like protein complex that consisted of a cellulose binding domain (CBD), cohesins, dockerins, and scaffoldins. When properly assembled, this protein complex was able to bind to a cellulose matrix within a water filter and degrade free-flowing phthalates within the water.

Based on the innovations that the IFB-GDansk team was able to make, our team was specifically drawn to the functionality of the CBD subunits that made up that backbone of the EDC-Seas protein complexes. With both the ability to bind to cellulose with a high enough affinity to resist aqueous elution as well as the capacity to mount additional protein subunits on it, our team began wondering about the ways we could use CBDs to tackle wildfires.

Theoretical Basis

Cellulosomes

A cellulosome is a large, multi-enzyme protein complex produced by certain cellulolytic bacteria (such as Clostridium thermocellum) that efficiently breaks down plant cell wall polysaccharides like cellulose and hemicellulose. It is composed of a scaffoldin protein, which acts as a structural backbone, and multiple enzymatic subunits that attach to it through specific cohesin–dockerin interactions. This highly organized structure allows enzymes to work synergistically, positioning them close together on the cellulose surface to maximize degradation efficiency.

Figure 1. (a) Schematic representation of a basic cellulosome in Clostridium thermocellum. (b) Molecular representation of cohesin-dockerin complexes (c) structural depiction of the type I (left) and type II (right) interfaces between the cohesin and dockerin modules [1].

The cellulose binding domain (CBD) — also called the carbohydrate-binding module (CBM) — plays a crucial role by anchoring the entire cellulosome complex to the insoluble cellulose substrate. Without the CBD, the enzymes would diffuse freely in solution, greatly reducing their ability to act on the solid cellulose fibers. By tightly binding the scaffoldin (and thus the whole enzyme complex) to the cellulose surface, the CBD ensures prolonged contact, enhanced substrate accessibility, and increased catalytic efficiency, making the cellulosome one of nature's most effective systems for plant biomass degradation.

Bio-Based Flame Retardant Proteins

Bio-based flame retardant proteins are naturally derived or engineered biomolecules designed to reduce the flammability of materials in an environmentally friendly and sustainable way. Unlike conventional flame retardants that often rely on halogenated or phosphorus-based chemicals (which can be toxic or non-biodegradable), bio-based proteins use inherent biological properties — such as nitrogen, phosphorus, and aromatic amino acids — to promote char formation, limit oxygen access, and suppress smoke generation during combustion. Some bio-based flame retardant proteins that our team took a special interest in include:

• Casein – A phosphoprotein found in milk, casein is one of the best-known natural flame retardants. Its high phosphorus and nitrogen content promotes the formation of a stable char layer, which insulates and protects the underlying material from heat and oxygen. Casein has been used to treat textiles, wood, and biodegradable polymers [3].
• Soy protein – Abundant and renewable, soy protein's nitrogen-rich structure and thermal stability make it a promising flame retardant when cross-linked or combined with other bio-additives (like phytic acid). It has shown effectiveness in biopolymer composites and natural fibers.
• DNA – The phosphate groups in the DNA backbone release phosphoric acid upon heating. This acid promotes dehydration of the underlying material and catalyzes the formation of a protective carbonaceous char layer, which insulates the substrate from heat and oxygen. The nitrogen-containing bases (adenine, thymine, cytosine, and guanine) can also decompose to release non-flammable gases such as nitrogen and ammonia during heating. These gases cause the char layer to expand and further protect the underlying material by diluting flammable volatiles and cutting off oxygen supply [2].

Overall, these bio-based flame retardant proteins offer many advantages that allow FloraGuard to meet the requirements of our research question. Their biodegradability, low toxicity, and renewability, made them attractive for designing a sustainable and safe flame retardant alternative that could also be produced with synthetic biological techniques.

References

1. Artzi, L., Bayer, E. & Moraïs, S. Cellulosomes: bacterial nanomachines for dismantling plant polysaccharides. Nat Rev Microbiol 15, 83–95 (2017). https://doi.org/10.1038/nrmicro.2016.164
2. Alongi, J., Carletto, R. A., Di Blasio, A., Carosio, F., Bosco, F., & Malucelli, G. (2013). DNA: a novel, green, natural flame retardant and suppressant for cotton. J. Mater. Chem. A, 1(15), 4779–4785. https://doi.org/10.1039/C3TA00107E
3. Alongi, J., Carletto, R. A., Bosco, F., Carosio, F., Di Blasio, A., Cuttica, F., Antonucci, V., Giordano, M., & Malucelli, G. (2014). Caseins and hydrophobins as novel green flame retardants for cotton fabrics. Polymer Degradation and Stability, 99, 111–117. https://doi.org/10.1016/j.polymdegradstab.2013.11.016
4. Dong, L., Xue, Y., Huang, H., Shen, D., Gao, W., Xu, F., Weng, Y., & Zhang, Y. (2023). Facile synthesis of soybean protein-based phosphorus-nitrogen flame retardant for poly(lactic acid). Polymer Degradation and Stability, 214, 110412. https://doi.org/10.1016/j.polymdegradstab.2023.110412