DESCRIPTION

ABSTRACT

Over 23.5 million Americans face food insecurity or have limited access to affordable and fresh produce, leading to nutrient deficiency. Aquaponics is a pragmatic solution to address food insecurity, but maintenance and costs are barriers to implementation. Lambert iGEM’s AgroSENSE utilizes modular hardware, nutrient biosensors, and iOS/Android compatible software to monitor and analyze nutrient levels and environmental conditions to optimize plant growth. Lambert iGEM's Arduino sensors measure environmental conditions while biosensors are utilized to monitor phosphate and nitrate nutrient balance. The team characterized a BioBricks based on E. coli’s native Pho signaling pathway and began cloning to characterize the Nar pathways. The expression of GFP in the presence of these nutrients is analyzed by Fluoro-Q, an improved frugal fluorometer. The data will be quantified by the Agro-Q mobile app, enabling end-users to make informed decisions regarding aquaponics systems. With an emphasis on integration of educational curriculum, AgroSENSE serves as a model for future agricultural biotechnology innovations.

Figure 1. AgroSENSE follows a circular workflow beginning with biosensing nutrients in aquaponics systems and ending with informing end users of how they should proceed with maintenance.

DEFINING THE PROBLEM

The United States Department of Agriculture estimates that 39 million people across the United States face food insecurity, or the lack of fresh produce for consumption [1]. These people are limited to either highly processed junk food or fast foods which have been linked to chronic illnesses, cancer, cardiovascular disease, diabetes, hypertension, and even premature death [2]. Food deserts are defined as areas with limited access to affordable and healthy food options (especially fruits and vegetables) and are characterized by proximity to grocery stores and access to transportation. Atlanta is the third-largest food desert in the nation, with over one in every four Atlantans living in neighborhoods defined as food deserts [1]. Despite efforts by multinational aid organizations and local food banks to curb rates of malnourishment and subsequent health problems, they continue to skyrocket year after year.

INSPIRATION

Lambert High School is located in the greater Atlanta area, which is the third-largest food desert in the nation.. To address access to nutritious food, Lambert Smart Agriculture, a group of students at Lambert High School experimented with hydroponics and automation to produce efficient, locally sourced vegetables such as kale and lettuce. Hydroponics is a type of agriculture, which is a method of growing plants, usually crops, without soil, by using mineral nutrient solutions in an aqueous solvent [3]. Lambert iGEM's inspiration for this year’s project was sparked by iGEM members who were also in Smart Agriculture. Lambert iGEM members participating in the club pitched the integration of synthetic biology with hydroponics at the team's initial brainstorming meeting in February. Team members discussed common diseases faced in hydroponics systems such as root rot. However, through more in-depth conversations, the team discovered that non-nutrient specific sensors have resulted in Smart Agriculture members estimating the concentrations of the distinct nutrients, phosphate, nitrate, and potassium rather than adding specific fertilizer concentrations based on the existing amount of nutrients in their systems. This led to plant growth variability in their hydroponics systems. In addition, fertilizer solutions add a significant cost to hydroponics. To address this, Lambert iGEM decided to research aquaponics, where fish waste produces many nutrients for plants in conjunction with developing nutrient biosensors, to have a more balanced system.

WHAT IS AQUAPONICS?

Aquaponics is the cultivation of plants using an alternative to soil as the growth medium, typically an aqueous solution, with the excrement of aquatic animals used as nutrient supplements [4]. Aquaponic systems provide an efficient, eco-friendly method of increasing food production to supply those who lack access [5]. Due to the simplicity of the low-input nature of aquaponic systems, just initial modification is necessary to get the system started, then the fish and the plants create a symbiotic relationship by recycling nutrients such as phosphate and nitrate. Since food security issues disproportionately affect people residing in low-income urban areas, we envision city-friendly vertical systems. These systems conveniently save space and can be placed on rooftops or in community gardens. Urban aquaponic systems provide a handful of benefits that don’t come with traditional farming; such as, limiting carbon emissions by eliminating factors like food transportation and storage, and their ability to be grown anywhere, with or without arable land, which can help provide food in the modern era of urbanization [6]. The yield from aquaponics also tends to be tastier, more nutritious, and with fewer traces of pesticides.

BARRIERS

Unfortunately, Lambert iGEM's research led to the discovery that aquaponic systems have some inherent barriers that make their widespread adoption difficult. The first is that aquaponics is a relatively underutilized concept, which means there is not as much information available on how to assemble, operate, and maintain systems. The second hurdle involves the challenge of combining two complex habitats, one aquatic and one herbaceous, into one codependent ecosystem. Variation in environmental factors, like nutrient levels, pH, and temperature, can be fatal to fish and plants outside of optimal levels. Further, depending on the type of produce being cultivated, the stage of plant growth, and the fish being nurtured, the optimal environmental conditions may vary dramatically, making it critical to understand the precise state of the aquaponics system at all times. As a result, these systems can be difficult to maintain and complex in nature, which disincentivizes users from continuing to use them. By creating an efficient, user-friendly system, Lambert iGEM hopes to eliminate these barriers and promote the proliferation of aquaponic systems. This could facilitate self-sufficient food production better than traditional agricultural methods, creating a higher yield to feed nutritious food to more people. Moreover, the team hopes to incentivize more people to become aquaponic farmers by eliminating hurdles involved with aquaponics.

Figure 2. Phosphate and Nitrate deficiency in plants leads to debilitated plant growth.

OUR APPROACH

Lambert iGEM has created synthetic biology sensors for nitrate, nitrite, and phosphate, all essential nutrients to plant growth for applications in aquaponics and hydroponics systems. As proof of concept, the team built a hydroponics system this year to test nutrients levels in the water using its biosensors. Lambert iGEM engineered an Arduino sensor system that monitors optimal conditions for plants to grow like pH, ambient temperature, water temperature, humidity, carbon dioxide levels, and light intensity. The team's biosensors quantify the amount of phosphate and nitrate nutrients through the expression of GFP, which can be measured using Lambert iGEM's frugal fluorometer, Fluoro-Q, an improvement from the 2019 Lambert iGEM team’s project. This data can be collected and monitored with the mobile app, Agro-Q. AgroQ will alert users of the conditions in the system allowing remote updates. To help encourage the use of these systems, the additional app, AgroSENSE, has information and guidance to build, maintain, and optimize the use of the aquaponic systems while also providing recipes to create nutritious meals. Further, to manage algae buildup, Lambert iGEM improved upon the frugal bead homogenizer, OpenCellX from the 2019 Lambert iGEM team’s project. OpenCellX would break down the algae so its DNA can be sequenced to determine what species it is and identify the cause of growth in the system. Through this system, Lambert iGEM aims to promote a multifaceted, community-driven approach to aquaponics, providing a sustainable approach for maintaining nutritious diets.

REFERENCES

[1] Rhone, A. (2020, August 26). Food Access Research Atlas. Retrieved October 26, 2020, from https://www.ers.usda.gov/data-products/food-access-research-atlas.aspx

[2] Poor Nutrition. (2020, August 24). Retrieved October 26, 2020, from https://www.cdc.gov/chronicdisease/resources/publications/factsheets/nutrition.htm

[3] Woodford, C. (2020, April 19). What is hydroponics? - A simple introduction. Retrieved October 26, 2020, from https://www.explainthatstuff.com/hydroponics.html

[4] White, H. (2020, August 27). What is Aquaponics? Retrieved October 26, 2020, from https://www.theaquaponicsource.com/what-is-aquaponics/

[5] Schafer, K. (2014, October 02). Aquaponics: A sustainable solution to food insecurity? Retrieved October 26, 2020, from https://www.theguardian.com/global-development-professionals-network/2014/oct/02/aquaponics-a-sustainable-solution-to-food-security

[6] José Palma Lampreia Dos Santos, M. (2016). Smart cities and urban areas—Aquaponics as innovative urban agriculture. Urban Forestry & Urban Greening, 20, 402-406. doi:10.1016/j.ufug.2016.10.004