Japanese researchers turn discarded udon noodles into biodegradable paper: How it works
&imwidth=600&imheight=450&format=webp&quality=medium "Japanese researchers turn discarded udon noodles into biodegradable paper: How it works")
Representative image. Photograph: (Unsplash)
Researchers in Kagawa are turning discarded udon noodles into biodegradable, water-resistant "paper" using acetic acid bacteria. Led by Professor Naotaka Tanaka, the project reduces food waste by creating local, eco-friendly recycling networks.
Intending to reduce food waste and design new local products, researchers in Kagawa, Japan, are turning discarded udon noodles into biodegradable "paper" using microorganisms. The process is helping to transform unwanted wheat noodles from local restaurants into thin sheets of cellulose with a shape similar to old Japanese washi paper.
The project was developed under the initiative of Professor Naotaka Tanaka of Kagawa University's Faculty of Agriculture, who developed the technology by applying research on microorganisms and cellulose-producing bacteria. Kagawa Prefecture is well known for Sanuki udon, a regional noodle speciality that attracts visitors from around the world. However, a huge amount of noodles also went unsold or were discarded after losing their essence once boiled and left sitting for too long.
"With large amounts of udon noodles being discarded in Kagawa Prefecture, I thought repurposing them could help reduce food waste," Tanaka said. "The process of converting discarded udon into sugar was relatively simple, so I decided to put the idea into practice," the Professor added.
How is biodegradable paper made from discarded noodles?
To create the paper-like material, leftover noodles are first mixed with water and blended into a slurry. Enzymes are added to convert the starch into glucose following the introduction of acetic acid bacteria in the mixture. Over several days, the bacteria form a cellulose membrane on the surface of the mixture. The membrane is then placed on trays and left to air-dry, avoiding the arch of traditional papermaking methods.
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One serving of udon can yield five to 10 sheets of A4-sized paper. Tanaka said the resulting material is stronger against water and tearing than conventional paper and can naturally break down in soil with the help of microorganisms. He initially developed the microbial paper about 16 years ago to demonstrate to students how microorganisms produce cellulose membranes.
Tanaka stated that he was impressed by the material's lightweight yet durable nature and explored its potential as a solution to food waste in Japan's Kagawa Prefecture. "I wanted to contribute to society by making use of the region's unique characteristics," he said.
Around 2020, the university shared its paper-making technology free of charge with a local social welfare organisation after researcher Tanaka suggested it could provide suitable work opportunities for people with disabilities. The project initially faced challenges, including bacterial contamination and mould growth, but production stabilised after the materials were cultivated in temperature-controlled boxes.
Currently, the facility produces about 100 sheets of paper each month, which are purchased by the university, creating a local recycling network involving restaurants, researchers and welfare workers. Partner restaurants supply leftover noodles that would otherwise be discarded.
The eco-friendly paper has already been used for promotional items and artwork, while researchers are exploring potential applications such as biodegradable fishing bait. In exchange for the noodle waste, the university provides restaurants with data on food waste volumes and weather patterns to help them better forecast demand and reduce waste. Tanaka hopes the initiative can become a model for tackling food waste sustainably.
