Safety

Safety equipment

The lab that we work with, Counter Culture Labs, is equipped with several safety measures that aim to keep all occupants of the labs safe. All of the safety precautions that are used in Counter Culture Labs are in accordance with the federal biosafety levels. All occupants in CCL have access to an eyewash station, masks, first aid kits, spill cleanup kits, fire extinguishers, and a biosafety cabinet. This ensures that if an accident is to occur, we are able to properly handle it.

PPE

At our lab we take measures to remain as safe as possible as we are ultimately responsible for our own safety. All CCL occupants also are properly equipped with PPE including gloves, lab coats, and close-toed shoes which prevent us from any sort of harm caused in the lab.

Storage and Disposal

All items stored in the lab are labeled with the name of the creator, the chemical, the date made, and any potential hazards the chemical may pose. For disposal we autoclave or bleach and live bacteria before disposing of them

 Finally, all members are also tasked with at least one cleaning action that is listed on the sign-in sheet to ensure that our environment is kept to a set standard of cleanliness.

To learn more about safety procedures and policies that are followed by all KhanLabSchool iGEM Team members, we recommend checking out the CounterCulture labs BioSafety Level 1 policies at BioSafety Level 1 policies - Counter Culture Labs.

Methane

While we hoped to work with methane to test our bacteria, we ever got around to that point in the lab due to time constraints. However we still discussed the safety of handling methane with Nikira Labs. Our plan was to only use methane below the concentrations of both the lower flammability limit - 50,000 ppm - and the 90 exposure limit, - 5,000 ppm [1]. Somewhere around 1,000 ppm is more than sufficient for our testing as the upper bound for landfill emissions is supposed to be at maximum 500 ppm as set by the epa [2].

Open release

A major concern about our project safety comes up when we consider it’s full vision. While in the lab, genetically edited bacillus is safe, there are questions of how to safely introduce it into a landfill environment.

We split these concerns into two parts, how to contain the bacillus to the landfill, and how to eradicate the genetically edited bacillus if need be.

Containment:

We came up with a couple of options for containment, both hinging on the fact that landfills have relatively high concentrations of methane. One could make it such that methane is the only source of energy for B. subtilis, making it impossible for them to leave containment. The issue with this, is that similar bacteria already exist (other methanotrophs), and generally, without the ability to also use sugar for energy, they struggle to thrive in landfills.

We could implement this differently, only allowing metabolism of sugar in the presence of methane, or producing toxin in the lack of methane, which work significantly better, but are much harder to implement.

Kill switch:

We could develop two major types of kill switches, those that require a particular compound to kill the B. subtilis and those that kill the bacteria when a given compound is lacking.

The latter is similar to the lack of methane based kill switch proposed earlier, but is hard to implement. The former is much easier to implement due to the variety  of inducible promoters, but requires the addition of an additional substance to the landfill to kill bacteria, and is less useful for containment purposes.

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References

EPA. (2011). Emission Standards for Municipal Solid Waste Landfills (Rule 4-43). Retrieved September 28, 2024, from https://www.epa.gov/sites/default/files/2017-08/documents/va_ch_40_part_ll_article_43.pdf

National Research Council, Division on Earth and Life Studies, Commission on Life Sciences, Board on Toxicology and Environmental Health Hazards, & Committee on Toxicology. (1984). Emergency and Continuous Exposure Limits for Selected Airborne Contaminants: Volume 1. National Academies Press.