

A toilet break on Mars could be a constructive use of astronauts’ time. And it isn’t just human urine that’s suitable as building material.
Algae, already used to make blue lemonade, are showing their versatility here too.
The founders of a US startup licensed a proprietary process from their former University in Colorado, harnessing microalgae to develop ersatz cement.
The blue alga – also known as cyanobacteria – is grown under LED light in large tanks with nutrient-rich salt water and oxygen. The next step, a trade secret, sees the algae converted into mineral substances.
The resulting sludge is dried and mixed with naturally-occurring binding agents to form a CO2-neutral cement alternative.
This founder, meanwhile, is using bacteria to create cement-free tiles.