Water pollution is a global concern, with an estimated 300-400 megatonnes (600-800 billion pounds) of industrial waste being discharged into bodies of water annually. As materials scientists, we are developing an ‘engineered living material’ that could potentially convert chemical dye pollutants from the textile industry into harmless substances. This project aims to tackle the environmental and humanitarian issues associated with water pollution.
The ‘engineered living material’ we are working on consists of programmed bacteria embedded in a soft hydrogel material, which was first detailed in a paper published in Nature Communications in August 2023. The hydrogel, made mostly of water, is created using a natural, biodegradable seaweed-based polymer called alginate.
The goal of choosing the alginate hydrogel was to provide a suitable environment for the growth and development of the bacteria. Specifically, we embedded photosynthetic bacteria called cyanobacteria into the hydrogel, which were then 3D-printed into custom shapes to maximize their ability to take in light, CO₂, and nutrients from the surrounding environment.
The genetically engineered cyanobacteria produce an enzyme called laccase, which can transform toxic pollutants into harmless substances. We conducted tests using indigo carmine, a common industrial wastewater pollutant, and observed our material successfully removing the color from the dye.
To ensure that our material does not cause additional pollution, we also engineered a ‘kill switch’ into the bacteria to eliminate them using a harmless chemical found in common items such as tea, coffee, and chocolate.
Our work in developing living materials is contributing to an evolving field, offering potential solutions to pressing environmental problems. This article is reprinted from The Conversation, and was written by Jonathan K. Pokorski and Debika Datta of the University of California, San Diego.
