Photosynthesis is maybe the most important chemical process on Earth, turning sunlight and CO2 into the oxygen we breath and the food we eat. This process can be reversed, however. Danish researchers were the first to demonstrate how biomass can be broken down by sunlight in the presence of an enzyme and turned into useful chemicals like biofuels or renewable plastic.
“This is a game changer, one that could transform the industrial production of fuels and chemicals, thus serving to reduce pollution significantly,” says University of Copenhagen Professor Claus Felby, who heads the research published in Nature Communications.
“It has always been right beneath our noses, and yet no one has ever taken note: photosynthesis by way of the sun doesn’t just allow things to grow, the same principles can be applied to break plant matter down, allowing the release of chemical substances. In other words, direct sunlight drives chemical processes. The immense energy in solar light can be used so that processes can take place without additional energy inputs,” says Professor Claus Felby.
Breaking down plant material is mainly done using industrial processes with high energy inputs, and can take a long time. The process developed in Denmark relies on lytic polysaccharide monooxygenases, a natural enzymes also used in industrial biofuel production, which aided by the sun’s energy can break down plant material in less than 10 minutes.
Tests were made on biomass — straw or wood — sprinkled with chlorophyll and the enzyme. The sun’s rays then break the sugar molecules inside the biomass into smaller constituents.
“We use the term “reverse photosynthesis” because the enzymes use atmospheric oxygen and the Sun’s rays to break down and transform carbon bonds, in plants among other things, instead of building plants and producing oxygen as is typically understood with photosynthesis”, says Postdoc Klaus Benedikt Møllers
Using this process biofuels could be made much faster. Methanol, an important fuel, could be sourced directly and at ambient conditions without additional energy inputs, for instance.
There’s reason to believe this reaction occurs naturally on the planet, though no one has reported it yet.
