Phytomining: Growing a U.S. Solution to the Nickel Supply Crisis

Dr. Jeongim Kim, associate professor and head of the Biochemical Genetics Lab for the Horticultural Sciences Department, is leading a new project providing an alternative solution to the United States’ growing demand for nickel, a pressing domestic resource challenge. She joined this project in 2023 and was invited by UF’s then-Provost and Senior Vice President of IFAS since 2020, Dr. J Scott Angle, to continue his ongoing research aimed at transforming how the U.S. sources this critical mineral by using plants.

The project “Nickel Farming: Improving a U.S.-Native Hyperaccumulator Plant for Commercial Cultivation” focuses on developing a native plant species capable of extracting nickel from the soil through a process called “phytomining.” Phytomining is an innovative and sustainable method of extracting valuable metals from soil using certain kinds of plants. The team also includes Dr. Kevin ‘Xu’ Wang, a phenomics expert from the Department of Agricultural and Biological Engineering, and Bellus Ventures, a business partner, and they received a $1.9 million grant from the U.S. Department of Energy’s ARPA-E program in December of 2024.

Certain species, known as hyperaccumulators, have the unique ability to absorb high concentrations of metals such as nickel, cobalt, or zinc through their roots. They are cultivated on metal-rich marginal lands that are often unsuitable for conventional agriculture or mining, due to factors such as poor soil quality, low fertility, limited water availability, steep slopes, or contamination. Once mature, the plants are harvested, dried, and processed to recover the metal from their biomass.

Phytomining not only offers an environmentally conscious alternative to traditional mining practices, but it also helps rehabilitate degraded land and leads to the development of circular, low-impact approaches to resource extraction. The hope is that renewable energy projects like this, where traditional methods would not be practical, can use native plant restoration to become economically viable. The U.S. is almost entirely dependent on imported nickel, but we have untapped resources in our soil and in our native plant biodiversity.

Streptanthus polygaloides plants is shown with an orange marker in a green plastic pot. The plant is stringy with small yellow flowers throughout. The background is minimally seen but glimpses the interior of a growth chamber. — *Streptanthus polygaloides* grown under controlled conditions in a growth chamber. The native hyperaccumulator species is being studied for its potential to sustainably extract nickel from soil through phytomining.

Advancing Phytomining with Native Plant Species

Phytomining farms are already in operation in Europe and have been for almost a decade. “The last nickel mine in the U.S. will close in 2026, and currently over 90% of nickel is imported,” explained Dr. Kim. “Europe has already started using plants for nickel mining. The U.S. wants to have a similar supply route using plants. That’s how this phytomining project started.” Researchers attempted to adopt these European species in the U.S. decades ago. Unfortunately, those species quickly proved to be very invasive and degraded Oregon’s ecological landscape. “Using these non-native species in California is problematic. We needed to find another solution,” stated Dr. Kim. Initially introduced by Dr. Angle as a strong alternative, Streptanthus polygaloides, more commonly known as Milkwort Jewelflower and part of the Brassica family, naturally grows in serpentine, nickel-rich soils, and is native to the Sierra Nevada foothills of California into Oregon and Nevada. Streptanthus polygaloides can also store up to 0.6% nickel by dry weight—an encouraging baseline. But the wild species isn’t optimized for farming.

Close-up of a purple Streptanthus polygaloides flower inside a growth chamber. — A purple-flowered Milkwort Jewelflower

Dr. Kim went on to explain, “The problem is, especially with this species, it can extract nickel, but not as much as the European species and the plant itself is very small. Little research has been done, and there’s no seed available.” Seed scarcity is not just an issue with the U.S. native species, but the European species as well. “The main objective of our project is to maximize the biomass and nickel extraction efficiency of this species.”

The Biochemical Genetics Lab is doing just that by combining classical plant biology with cutting-edge technology to genetically engineer a plant that can yield more nickel, a plant that will eventually be used as the basis to create a system that can be scaled, monitored, and optimized for real-world use. “This species belongs to the Brassica family. Early in my career, I studied a species called Arabidopsis, which is a model plant species also belonging to Brassica, so it makes me feel more comfortable working with this species. The two species share many metabolic pathways; that excites me. Using my knowledge to develop new plant genetic material that can contribute to energy fields and help solve some energy issues excites me as well,” relayed Dr. Kim.

Close-up image of a young Streptanthus polygaloides plant growing in a white, gel-like tissue culture medium, used to support early development and genetic modification in the lab. — A tissue culture of *Streptanthus polygaloides* in an early growth stage. This method allows Dr. Kim’s lab to propagate rare native plants and accelerate genetic improvements.

The project is still in its early stages. The team is currently working on genome sequencing the species for the first time, which will serve as the foundation for future gene-editing efforts. Drawing on her expertise with model organisms like the related Arabidopsis, Dr. Kim and her lab are applying modern molecular and synthetic biology approaches to understand and enhance the plant’s genetic potential.

It’s not just genetics driving this work. The project will also integrate AI-powered growth monitoring systems to track how plant modifications affect growth and metal uptake in real time. These smart systems will provide data to refine cultivation strategies and improve field performance.

Photo of a genetically modified Streptanthus polygaloides plants in sequential order with larger leaves and stems, demonstrating increased biomass achieved through research aimed at improving its nickel-harvesting potential. — A modified *Streptanthus polygaloides* plant, engineered by Dr. Kim’s lab, shows increased biomass compared to its wild form. Boosting the plant’s size is a key step toward making phytomining commercially viable for U.S. nickel extraction.

Building Domestic Supply Chains for Critical Minerals

Collaborations with industry are already underway. Partner Bellus Ventures, an investment management firm for the clean energy transition, is already helping to plan for technology transfer and commercialization. If successful, this could lead to new supply chains for U.S.-sourced nickel that rely not on mining, but on agriculture.

The long-term possibilities extend far beyond nickel. “This project started with nickel. Nickel is an essential element needed for certain industries, however, there are other elements that could have supply issues. Some lands may have marginal levels of those elements, so I envision that we can use this technology to expand and extract other elements as well,” explained Dr. Kim. The methods developed in this project could be adapted to harvest other valuable elements and applied to space exploration scenarios—where plants might help extract metals from extraterrestrial soil.

Petri dish showing two soil types: brown regular soil on the left and reddish, rocky serpentine soil on the right, used to study metal absorption in phytomining plants. — Side-by-side comparison of regular soil (left) and serpentine, nickel-rich soil (right, with red tint). The red color indicates high iron and metal content, common in serpentine soils where Milkwort Jewelflower naturally thrives.

For now, the team is focused on laying a solid scientific foundation. This is an ambitious, innovative project, and if successful, it could fundamentally change how mineral extraction is approached, all while being more sustainable and environmentally responsible.

Supporting Experiential Learning through Real-World Research

Dr. Kim’s lab isn’t just about cutting-edge research; it’s also a place where students gain hands-on experience that can shape their future careers. Students from many academic backgrounds, including pre-med, engineering, and plant science, are contributing to the project in significant ways. Dr. Kim’s lab studies various phytochemical biosynthetic regulations using crops like tomatoes and other medicinal plants, but the technology is the same, and most of her students are directly contributing to this project. From plant care and seed harvesting to molecular work such as DNA cloning, each student helps to push this research forward.

For many of these students, working on such practical, in-lab experiences provides a well-rounded understanding of solving real-world problems. As Dr. Kim explains, “This is a good opportunity for them to be exposed not only to this project, but also to what is happening in science today – what science can do. If they are exposed to this kind of field in an early stage of their career, it can help them to figure out their future career goals as well. Particularly with this project, it is very practical. [Students can] actually engineer a plant and contribute something tangible to society that they can be proud of,” explained Dr. Kim.

The opportunity to be involved in groundbreaking research empowers students to see the direct impact science can have in solving issues that extend into many sectors of society. We are excited to see what is next for Dr. Kim’s lab. In the meantime, Dr. Kim continues to lead innovative research applying advanced techniques like genome sequencing and gene editing to optimize the ability of these plants to extract more nickel, which could potentially revolutionize the U.S. nickel supply chain.