New Material: Transformed Bacteria Eat Plastic And Spit Out "Spider Silk"

Scientists from Rensselaer Institute of Technology and Argonne National Laboratory have worked together to transform Pseudomonas aeruginosa into biodegradable "spider silk". The silk protein obtained is similar to the silk used for spider web weaving, and is expected to be used in the textile, medical and cosmetics industries. This is the first time that scientists use bacteria to transform polyethylene plastics into high-value protein products. Related papers were published in the recent journal Microbial Cell Factory.

Pseudomonas aeruginosa can naturally use polyethylene as a food source. In the latest research, researchers have modified this bacterium to convert polyethylene into silk protein, and its efficiency and yield of silk protein production can be comparable to those of bacteria strains traditionally used for silk protein production.

The research team said that in order to allow bacteria to ferment polyethylene, the first thing to do is to "simplify" the plastic. Just as humans cut food into small pieces and chew it before eating, it is difficult for bacteria to directly "eat" polyethylene long molecular chains or polymers. In view of this, the research team heated the plastic under pressure and depolymerized it to obtain a soft, waxy substance; Then a layer of plastic wax is coated on the bottom of the flask as a nutrient source for bacteria; The transformed bacteria can eat the plastic and spit out "spider silk".

Researchers pointed out that spider silk is nature's Kevlar fiber, which is almost the same strength as steel, but its density is 6 times that of steel, so it is very light. As a bioplastics, it is flexible, non-toxic, biodegradable and other characteristics, is an excellent material to avoid persistent plastic pollution.