The textile and leather industries pollute water through dyeing and tanning, and plastic pollution from synthetic fibers. In particular, the chemicals used by synthetic chemical manufacturers to dye clothing, especially black dyes for leather, pollute the environment. To solve this problem, researchers at Imperial College, London, bacteria produced Eco-friendly, self-pigmenting, animal-free leather.
Researchers studied a group of bacteria called . Komagata Eibacter We produce an environmentally friendly leather alternative called . bacterial cellulose. They explained that bacterial cellulose is advantageous because it is durable, long-lasting, easily grown from waste materials such as fruit juice, and biodegradable. It is also cheap to produce and is used in many industrial applications, including electronic equipment and wound dressings to cover and protect wounds. Designers love it because it's sustainable and uses more natural materials instead of petroleum-based materials.
The researchers wanted to modify the bacteria's genes so that they could produce both bacterial cellulose and a black pigment that protects from sunlight and absorbs harmful substances. melanin. They hypothesized that melanin could make cellulose more versatile by making it stronger and protecting it from sunlight, allowing it to be used in new applications such as environmentally friendly sunscreens and pollutant-absorbing materials. I did.
To do this, the researchers Komagata Eibacter 2 types of liquid food, or culture media: One was made from glucose and the other from coconut water. They sterilized these fluids to make sure they were clean and sterile. They introduced new genetic material into the bacteria's DNA using a process called . electroporation. The new genetic material contained a special type of circular DNA that enabled the bacteria to produce melanin.
First, the genetically modified bacteria are grown normally. They then added ingredients that “start” melanin production, such as L-tyrosine, the building block of melanin, and copper sulfate, a catalyst that accelerates the process. To see how much melanin the bacteria produced, they measured how dark the culture medium became. This was a good indicator of melanin levels. To see if different conditions change the amount of melanin produced by bacteria, the researchers experimented with different pH levels, amounts of salt, and metals that can affect the amount of melanin produced by bacteria. I tried.
Next, the researchers Komagata Eibacter They produce a special type of melanin called melanin that produces a dark brown to black color. eumelanin. To force the bacteria to produce eumelanin, the researchers further modified the bacteria's genes. Specifically, they added a gene that causes the bacteria to produce an enzyme called Tyr1, which helps stimulate melanin production. They used this genetic change to create a unique bacterial strain that could continuously produce eumelanin.
Once they had these genetically modified bacteria, they conducted experiments to control the amount of eumelanin produced by the bacteria. They used a method called pyrolysis, which allows scientists to use light to control the behavior of cells. optogenetics. In this case, exposing the bacteria to blue light caused them to produce more eumelanin. The light also caused some bacteria to produce another protein that turned red. The researchers used this red color to track how well the light-induced process worked. The researchers looked at how much eumelanin these engineered bacteria produced under different conditions so they could better control melanin production.
Researchers discovered that when bacteria produce melanin, they form a mat-like layer that retains moisture. They interpreted this result to mean that adding melanin to different materials can change their surface properties. To demonstrate how melanin can be used in leather-based products, researchers created sample items such as wallets and shoe uppers from a mixture of bacterial cellulose and melanin. It was confirmed that adding melanin to cellulose increases durability. The researchers found that the melanin remained stable even after treatments such as high-pressure steam and ethanol cleaning, meaning it was strong enough to withstand real-world use.
The researchers suggested that future work should discover enzymes that can produce melanin under acidic conditions, requiring less water for production. Especially when melanin is used in large-scale production, the process becomes more environmentally friendly and efficient if less water is used. Finally, they encouraged scientists and designers to continue working together to develop innovative ways to create sustainable textiles that make fashion more environmentally friendly.
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Source: sciworthy.com
