When it comes to drinking with a straw, there is no perfect option 鈥� plastic straws can release microplastics into your beverage, paper straws buckle and bend when they get wet and metal straws can damage your teeth. Now there is a solution: edible straws made by bacteria.
Qing-Fang Guan at the University of Science and Technology of China and his colleagues made straws out of bacterial cellulose, which is similar to the plant-based cellulose used to make paper but with a closer-knit molecular structure. It is synthesised by many types of bacteria when they feed on sugars.
The researchers collected the bacterial cellulose, then air dried it and dipped it in sodium alginate, a carbohydrate found in algae, to fill the pores in the cellulose that would otherwise absorb water. Sodium alginate also has the benefit of sticking to itself, so the researchers could simply roll the sheets of cellulose up into straws, with no glue required.
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The straws biodegrade far faster than plastic straws and don鈥檛 require any specific conditions to break down. As bacterial cellulose and sodium alginate are both used in existing food products, the straws are even edible. That said, the researchers don鈥檛 recommend eating them.
鈥淚t is edible, but not specifically designed for eating,鈥� says Guan. 鈥淚f I were to say what it tastes like, it probably tastes like coconut that has lost most of its moisture.鈥�
There are other biodegradable straws, but many of them are expensive. Not so for these edible straws. 鈥淭he preparation is not difficult, and the production of cellulose by bacteria requires almost no labour cost,鈥� says Guan. The entire production cost is about 0.3 US cents per straw, similar to the price of plastic straws and less than one-tenth the price of paper ones.
When the researchers tested the cellulose straws, they were far stronger than paper straws by every measure, whether dry or wet, and nearly three times as resistant to bending as either paper or plastic straws. The researchers are now working on other ways to use bacterial cellulose to replace non-biodegradable disposable products.
Advanced Functional Materials
