They continued experimenting and cultured a couple of species together, says Kuntla. To help the microbes draw nutrients more efficiently and grow better, the researchers began feeding them in liquid form, by boiling the flower petals in water to extract the cellulose and lignin from them and adding some extra carbohydrates.
“[The microorganism] feeds on that, and it grows,” explains Aamen Talukdar, an associate research scientist at Phool. “It produces molecules that are similar to the molecules in leather.”
This was the beginning of Fleather, which Phool began producing in 2021. To make the material today, the team begins with small volumes of the microbes in flasks in an incubator which are gradually grown larger by feeding them on the nutrient-rich flower liquid. Once the free-flowing liquid turns into a thick slurry, indicating that the microbe has attained maturity, the mixture is poured in trays to nudge the fibrous growth to take the form of a continuous sheet.
The tray is then rested for a few days during which an interconnected layer that resembles the rind on a brie cheese takes shape. It is then tanned using a tree-bark powder solution, dried, dyed and embossed with a snake or crocodile pattern. The end result is a soft, supple sheet that feels incredibly similar to animal hide leather.
So far Phool has been able to make several Fleather prototypes – wallets, sling bags, sandals and trainers – which, at first glance at least, look quite satisfactory.