Photo: TU Delft.
Henk Jonkers
Henk (Hendrik) Jonkers holds an MSc in Marine Biology (1989) and a PhD in Marine Microbiology (1999), both from the University of Groningen, and worked as a researcher at the Max Planck Institute for Marine Microbiology in Bremen from 1999–2006. He joined Delft University of Technology in 2006, becoming Professor of Bio-adapted and Sustainable Building Materials in 2021, and Departmental Director of Materials, Mechanics, Management & Design in 2024.
Jonkers pioneered the use of dormant bacterial spores (typically Bacillus species, chosen for alkaline tolerance) embedded in concrete alongside a nutrient source, activated by water and oxygen reaching a crack, to biologically precipitate calcium carbonate and seal the crack from within. Developed together with TU Delft civil engineer Erik Schlangen starting in the mid-2000s, and commercialized through the TU Delft spin-off Basilisk, this work has been applied in real infrastructure — including a railway underpass, hospital balconies, a bus lane, and tunnel and bridge repairs. Jonkers is also scientific advisor to Respyre, another TU Delft start-up, and was nominated for the European Patent Office's European Inventor Award in 2015 for the self-healing bio-concrete work.
Direct, foundational link to the Grow capability — bacterial self-healing concrete is among the clearest real-world examples of a living organism performing a structural repair function inside an otherwise inert building material.