Rachel Lee

Hi! I’m Rachel!

I’m a 16 year old activator @TKS interested in agritech, food insecurity, poverty, and the billion dollar question of how to feed 10 billion people on a hotter planet. I am super passionate about using agritech to improve agricultural productivity in developing countries. My life goal is to contribute to solving poverty and world hunger, and to help ensure that one day every single human being on the planet will have enough to eat. My area of expertise is in gene editing - previously I have worked on gene editing crops to increase yields, and proposed a transgenic strand of maize for Lesotho.

I am also the co-host and creator of the TechnoGypsie Podcast, a STEM podcast where we talk with experts in different emerging STEM fields about the field they are in, and how to use the technology to create a positive change in the world. If I’m not writing articles, reading research papers or networking with professionals, then I am outside running. I am an ultra runner obsessed with pushing my limits and discovering what I am truly capable of. Whether it’s skiing, rock climbing, kayaking, hiking, or kayaking, I am in my element when I’m outside in my beautiful home of Northern Ontario.

Improving the nutrient concentration of digestate to create a highly effective organic fertilizer for South Africa

70% (33 billion) of the Sub Saharan African population are farmers, and of these farmers, only 7% have access to fertilizer. [1] [2] This is the problem statement that I have been focused on understanding for the past three months.

Extremely low fertilizer application rates (over 3X less than the rest of the world) lead to crop yields much lower than the rest of the world, putting millions of people at risk of food insecurity. In my opinion, this problem is extremely underrated. So many agriculture focused solutions in Sub Saharan Africa are focused on improving farming tools and techniques (like irrigation and plows), but in my mind, I don’t understand why there isn’t a solution that is tackling the source of the problem: that Sub Saharan African soils are degraded, and plants don’t get the nutrients they need to thrive. Giving small scale rural farmers the access to cheap and effective fertilizer will cause yields to skyrocket as they did during the Green Revolution, and give farmers a steady source of income. My vision for the future of fertilizer production is a small scale fertilizer plant that operates in farmer’s backyard, is cheap to install and operate, uses all natural resources and produces effective, nutrient dense fertilizer. These are all the boxes that need to be checked for a solution to the fertilizer problem in Africa to be solved.

Landing on cyanobacteria as a way to bring digestate on par with synthetic fertilizer

I have been working on improving the by product of the anaerobic digestion process, digestate, to make it an effective fertilizer.

To start, I spent over one month diving deep into the anaerobic digestion process, researching the steps, inputs, outputs, costs, challenges and seeking to understand at a deep level how AD works. And then I shifted my research to digestate and sought to answer the question "why isn't digestate used as a fertilizer?", "what needs to be true for digestate to replace synthetic fertilizer?"

The answer is actually very simple: effectiveness. Digestate is not as good as synthetic fertilizer. So this begged the question "why?" What is the main reason digestate isn't as effective as digestate?

I came across a few reasons for this: digestate has a slow reaction time, digestate has a low content of NPK and digestate doesn’t survive as long as synthetics in the soil. I decided to focus on nutrient concentration. So currently I have been researching ways to cheaply increase the nutrient concentration of digestate, and decided that there were two ways to increase nutrient content: a change in the actual anaerobic digestion process to optimize for digestate instead of biogas, or a post-processing method to increase the nutrient levels of the digestate after AD.

My current hypothesis is that using Chlorella Sorokiniana microalgae-bacteria consortia to concentrate the nutrients in digestate after production could increase the amount of NPK in digestate. Research on using fermentation bacteria to increase nutrients has shown that this could increase NPK by 60-80%. [3] Chlorella Sorokiniana are a photosynthetic bacteria that use energy from the sun to convert carbon dioxide and water into carbohydrates and proteins. In AD, Chlorella Sorokiniana can convert the gases in the biogas into compounds that are the precursor to nitrogen and phosphorus creation.

Right now I am working on researching how this bacteria consortia would work, and how much the nutrient content would improve from it. This is a long process of talking with researchers and experts to validate or disprove my idea and learn from them. (And of course reading lots and lots of research papers).