ABC: use of Azolla for Biomining of heavy metals towards a Circular bioeconomy

Azolla is a small floating fern which grows vigorously due to its highly adaptable nature and symbiotic relationship with a nitrogen-fixing cyanobacteria. Azolla has an interesting root system, which can be discarded and regrown to suit a changing aquatic environment. This allows the plant to adapt to water contaminated with heavy metals, and provides a route towards exploiting this for repurposing Azolla into a biological biomining agent.

Each year, Europe produces an estimated 200,000 tonnes of spent consumer batteries. In addition to being a significant source of waste, these batteries also contain high levels percentage of hazardous heavy metals. To improve the sustainable use of batteries, conserve natural resources, and minimize environmental degradation, novel biotechnology routes towards heavy metal biomining are required.