Kitchen Sponges Help Breed Bacteria Better

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There’s a structural reason your sponge hosts so many microbes

Credit: Aleksei Filatov/Getty Images

Your kitchen sponge is full of microbes. However, repeated contact with food waste isn’t the only reason. A sponge’s unique structure also plays a part. It could even inspire a new way to grow bacteria for research, according to a study in Nature Chemical Biology.

One of the biggest challenges microbiologists face is culturing bacteria species that will not readily grow in a laboratory. Microbes can be very finicky and scientists don’t always know what conditions they need. Trina McMahon, a bacteriologist at the University of Wisconsin Madison, said that it was similar to trying to make pandas reproduce in a zoo. She wasn’t involved in the new study.

Sponges might be the answer. Petri dishes have a smooth, unpartitioned surface that is ideal for bacteria growth. However, sponges are dotted with hollow pockets, which are crucially not uniform. Lingchong You, a Duke University microbiologist and senior author of this study, says that there are different sizes of rooms in sponges. Some bacteria types are dependent on others for survival. They need space to form large communities. Others require relative isolation to avoid being killed by their neighbors. The perfect range of Sponges’ chambers is a mix of smaller and larger ones.

Although a sponge’s potential to be a bacteria farm may seem obvious, You say that it is difficult to demonstrate this experimentally. The researchers first created sponge-like environments on a computer. They found that different chamber sizes would allow for many different bacterial strains. These results were then replicated in cellulose sponges.

” It’s rare to see both [*] and [scenarios] combined so nicely,” McMahon said. But she notes that You’s team focused on Escherichia coli strains that were lab-engineered to be either dependent on one another or self-sufficient–so she wonders if the sponge technique will work with other sensitive bacteria. She says that there is a limit to what you can do using engineered strains.

Future experiments will prove whether purpose-built sponges can be used to support wild microbes. He recommends that you clean your kitchen sponge in the interim: “It’s probably the least clean item .”


This article was originally published with the title “Sponge Gunk” in Scientific American 326, 5, 20 (May 2022)

doi: 10. 1038/scientificamerican0522-20b


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