Sonnet155 bag in green and yellow by Lobke Beckfeld and Johanna Hehemeyer-Cürten

Sonnet155 is a "temporary handbag" made from discarded fruit peels

Berlin design students Lobke Beckfeld and Johanna Hehemeyer-Cürten have developed a translucent fruit-leather bag that dissolves in water and can be used to fertilise plants once it is no longer needed.

The Sonnet155 is made from two different post-industrial waste materials – fruit skins left over from juice production and short cellulose fibres sourced from a local textile factory.

Although it resembles a purse or tote with swooping top handles, the product has a lifespan closer to a disposable paper bag and is designed to degrade naturally with wear before it can ultimately be composted or recycled.

Small Sonnet155 bag in green and larger tote bag in yellow
The Sonnet155 bag comes in varying sizes, from small purses to larger totes

"We designed the bag as an upgrade to the ordinary paper bag but of course, we hope that it appeals to people in a strong way and will be worn, used and loved until it starts to dissolve," Hehemeyer-Cürten told Dezeen.

"Thus, it might also be a temporary handbag. The elegant shape transforms the material into a desirable product, which represents sustainability as a treat rather than a burden."

Green Sonnet155 carrier bag being dangled over water
Each has a unique texture created through the addition of small cellulose fibres

Sonnet155's key ingredient is pectin, a gelling agent that is extracted from the cell walls of the waste fruit and acts as a natural binder.

This is reinforced with cellulose fibres shorter than five millimetres long, which are filtered out during the industrial textile production process because they are too short to be turned into fabric.

Combined with warm water, the mixture is left to cure in a mould for up to five days before it is sewn together.

Yellow fruit leather developed by Lobke Beckfeld and Johanna Hehemeyer-Cürten
Beckfeld and Hehemeyer-Cürten extracted pectin from waste peels to develop their fruit leather

"The percentage of cellulose, as well as the length and density of the fibres, determine the structure and level of translucency and the resilience of the material," said Hehemeyer-Cürten.

"Natural pigments offer a range of colours from light to dark, translucent to opaque and dull to shimmering and the structure of the mould makes the material matt or glossy."

Once it is too worn down to be used, the material can be dissolved in warm water and recast to create a new bag of the same quality.

Alternatively, the cellulose can be filtered out with a sieve and reused, while the pectin can be repurposed as plant food.

Blue and yellow fruit leather patterns for the Sonnet155 bag
The material is cast into moulds in the shape of the bag

"Pectin is already used as a fertiliser in organic agriculture," Hehemeyer-Cürten explained.

"But as the majority of the cellulose waste generated during textile production is pre-dyed and therefore potentially harmful for the environment, we developed a lifecycle that allows the two main ingredients to be easily separated."

Beckfeld and Hehemeyer-Cürten, who are completing their master degrees at the Weißensee Academy of Art Berlin, are currently looking for manufacturers and industrial producers to collaborate with to make the Sonnet155 commercially available.

Green bag made from fruit peels by made from fruit peels by Lobke Beckfeld and Johanna Hehemeyer-Cürten alongside a swatch of the fruit leather in peach
The bags are then sewn together, much like real leather

Food waste was recently featured on Dezeen's list of the key materials that designers are relying on to create more sustainable products, due to the treasure trove of untapped natural compounds it contains.

Previously, Italian studio Carlo Ratti Associati has developed a prototype orange-squeezing machine that turns waste peels into bioplastic cups while engineer Carvey Ehren Maigue has turned discarded fruits and vegetables into solar panels that can generate clean energy from ultraviolet light.