Back in 2014, Royal College of Art graduate Julian Melchiorri developed a man-made “breathing” leaf that he claimed could invigorate indoor spaces and potentially improve space travel.
“Plants don’t grow in zero gravity,” Melchiorri told Dezeen in July. “NASA is researching different ways to produce oxygen for long-distance space journeys to let us live in space. This material could allow us to explore space much further than we can now.”
Melchiorri’s Silk Leaf Project was developed in collaboration with the Tufts University silk lab. The “leaf” consists of a silk protein into which chloroplasts have been embedded. Chloroplasts are the organelles in plants that conduct photosynthesis and allow plants to feed off the sun. According to Melchiorri, the silk has the unique ability to stabilize chloroplast, which has enabled Melchiorri to create “the first photosynthetic material that is living and breathing as a leaf does.”
And Melchiorri sees applications for the leaf beyond space travel. “It could [also] be used for outdoor applications,” he said. “So facades, ventilation systems. You can absorb air from outside, pass it through these biological filters and then bring oxygenated air inside.”
But Becky Ferreira, a contributor to Motherboard, took issue with Melchiorri’s invention. While lauding Melchiorri’s smarts and the leaf’s design, she pointed out that there was one major hole in his reasoning: “[P]lants most assuredly do grow in zero gravity. One of the most conclusive experiments on this subject was conducted on the International Space Station between October 2009 to September 2010. During that period, a number of Arabidopsis flowers (commonly known as thale cress plants) were successfully grown in closely monitored beds.”
In an email interview with the study’s lead author, Anna-Lisa Paul, Ferreira learned that, while plants do behave differently in space, they can survive well enough to provide a potential air and food source for future missions. Ferreira also wanted to know how long-term Melchiorri’s leaf would remain viable.
“After all,” Ferreira wrote, “the Silk Leaf is built from chloroplasts embedded into silk proteins. It may breathe in carbon dioxide and breathe out oxygen, but that does not make it sustainably photosynthetic, even on Earth. […] What happens to the glucose byproducts of the photosynthetic conversion? How long can the chloroplasts self-sustain in silk proteins?”
The debate recalls the popular but erroneous story about the American and Russian space agencies’ solutions to being able to write in space: The Americans spent millions of dollars to research and develop a zero-G pen while the Russians just used a pencil. For future space travelers, will silken chloroplasts really be necessary if natural plants work just fine? Perhaps.
Might still make some nice lampshades, though.