PRINCIPLES & PRACTICE: ENGINEERED BACTERIAL SOILS
Laura Maria Gonzalez
February 23, 2021
This week we explored the ethics, safety, and security considerations for a biological engineering application or tool and proposed governance policy goals and actions.
I chose to delve into a synthetic biology proposal for the genetic engineering of bacteria to create pressure sensitive soils. The project was proposed by researches at Newcastle University. The goal of this application is to provide an alternative to building foundations through the use of synthetic biomineralization, where engineered cells respond to pore pressure in the environment and synthesize new material to strengthen the soil. This technique could offer a better alternative to building foundations that currently require large excavations and infilling with carbon costly concrete.
Biomineralization is the process by which living organisms produce minerals, often to harden or stiffen existing tissue. Examples of biomineralization include sea shells and bones in mammals and birds. One notable example is the shell of the abalone. Abalone have the ability to bring together calcium and carbonate to form calcium carbonate while making small filaments of protein between the crystals that create a type of adhesive netting that interlaces with the calcium carbonate crystals to provide incredible strength.
The Thinking Soils project explored another type of biomineralization called biologically-induced mineralization. While the abalone has complete control over the crystal morphology, bacteria affect their surroundings to create crystals. They induce CaCO3 formation through the release of Urease, a by-product of bacterial metabolic activity. This can lead to an in crease in pH which causes calcium molecules to bind with carbon and trigger the formation of crystals. The project sought to combine this capacity, with the engineering of bacteria to sense pressure changes in their environment as an extension of material-based design computation.
Bacteria Induced CaCO3
PRIORITIES, TRADE-OFFS, AND ASSUMPTIONS
After generating the table, the set of governance options that I would prioritize are the creation of databases, establishment of local, national, and international oversight, creation of community outreach and workshops programs, and the logging of projects along with the development of tracking strategies.
These governance options were selected because they address the concerns of engineered bacteria based soils across a variety of scales and user groups. Throughout the table exercise, tradeoffs became immediately clear. For example, balancing biosecurity with equitable access and use. On the one hand, policies like licensure programs and registrations systems keep track of the use of the technology which would be important for widespread applications or applications where human safety is directly affected such as in building foundations. However, maintaining a tracking system for smaller scale use such as ceramics would hinder participation and use.
Protecting the environment as a category on it's own also has tradeoffs. Who are we protecting the environment for? Do the decisions reflect human interests only or do they also take into account non-human organisms? This is particularly important because of the edgeless quality of the technology. Once the bacteria is deployed into the ground it could seep beyond the intended boundaries and effect surrounding ecosystems. Another uncertainty of the technology is the immediacy of the effects of engineered bacteria based soils. Could the technology be used to cause harm before it could be detected or are the effects so slow that misuse could be contained?
Thinking Soils Concept Illustration, Dade-Robertson
USE, MISUSE, AND GUIDELINES
Using genetically engineered bacteria to alter soils has wide ranging applications beyond building foundations. For example, biomineralization could be used to develop ceramic alternatives that currently require large amounts of energy to fire at high temperatures ranging from 1700F to 2300F. Biomineralization can also be used to positively affect soil fertility, or combat shoreline erosion.
With these uses in mind I turned to iGem's Safe and Secure Project Design Guidelines as a useful framework for considering potential unintentional/ intentional misuses. The guidelines posed several questions such as:
Who will use the product? What opinions do these people have about your project?
Where will your product be used? On a farm, in a factory, inside human bodies, in the ocean?
If your product is successful, who will receive benefits and who will be harmed?
What happens when it's all used up? Will it be sterilized, discarded, or recycled?
Is it safer, cheaper, or better than other technologies that do the same thing?
Could others use your project in ways other than you plan to cause accidental or deliberate harm.
Red Abalone, CalOceans.org
Ceramics Alternatives, Ceramicartsdaily
Soil Fertility, Nationwide Blog
Foundation Alternatives, Paddy Eng
Erosion Control, Nantucket Chronicle
The questions brought to light three key areas for policy goals including enhancing biosecurity, ensuring equitable use, and protecting environmental health. The table below, adapted from JCVI "Synthetic Genomics: Options for Governance", explores the effectiveness of different proposed policy action through different stakeholders/users.
Text References:
Corral, Javier Rodriguez, et al. “Study of Bacteria Growth for the Development of Bio-Mediated Soil Improvement Methods.” Proceedings of the 4th World Congress on Civil, Structural, and Environmental Engineering, 2019, doi:10.11159/icgre19.183.
Dade-Robertson, Martyn, et al. “Design and Modelling of an Engineered Bacteria-Based, Pressure-Sensitive Soil.” Bioinspiration & Biomimetics, vol. 13, no. 4, 2018, p. 046004., doi:10.1088/1748-3190/aabe15.
Dade-Robertson, Martyn, et al. “Material Ecologies for Synthetic Biology: Biomineralization and the State Space of Design.” Computer-Aided Design, vol. 60, 2015, pp. 28–39., doi:10.1016/j.cad.2014.02.012.
“Can Biology Build a Better Battery?” Age Of Living Machines: How Biology Will Build the Next Technology Revolution, by Susan Hockfield, W W Norton, 2020, pp. 19–48.
The priorities were also set with a few assumptions in mind including that the technology will be monitorable/trackable. Soils volumes that have engineered bacteria could be detected amongst soil that do not and countries would cooperate with one anther to monitor conditions across borders. Another assumption is the desire of the public to engage with the technology and be a part of open community review sessions. There would need to be incentives to drive engagement over long periods of time, not just when things go wrong. And finally a receptiveness of synthetic biology as a craft skill in the case of individual users such as farmers or ceramicists.