San Diego biotech collects baby poop to reveal health of the microbiome

A lab employee at Persephone Biosciences pulled bacteria samples out of the tank in which they’re stored in small boxes at minus 200 degrees Celsius (minus 328 F). This is infant bacteria, which Persephone CEO Stephanie Culler calls her “company assets.” And where do they come from?

“This is our baby poop kit!” Culler said.

She is recruiting parents to donate stool samples from infants under the age of 8 weeks. The poop kit is in a black box. Culler opened the box and showed us its contents.

“Easy-to-use instructions, another reminder about filling out medical information, an easy-to-use scoop …” she said. “You scoop the poop and put it in this container.”

A healthy body means a healthy microbiome, which stores the bacteria that reside in the gut. And San Diego-based Persephone Biosciences is recruiting parents to donate their infant’s poop, so they can learn what babies have in their gut and what microbes they might be missing.

The company wants to collect a large, diverse set of stool samples to examine the gut biomes of babies across the country and compare them with possible health problems they have in later years.

“We know there has been a substantial increase in the last two decades of food allergies,” she said. “A lot of that can be coming from the microbiome.”


An employee of Persephone Biosciences has removed bacteria collections taken from infant stool samples from cold storage, where they are kept at minus 200 degrees Celsius, on Sept 8, 2022.

Culler said the health of the microbiome can determine the effectiveness of a child’s immune system. She said modern life is the source of many health problems, related to having little fiber in the diet and the extensive use of antibiotics.

“When we’ve done a comparison with the Amish, the Amish baby microbiomes are way more diverse,” Culler said of the culture that rejects many aspects of modern life.

Other modern inventions that Culler said can shortchange a baby’s gut health are C-section births and formula feeding. The study will compare those kids to ones who are born vaginally and who are breastfed. The company wants to follow the kids’ medical histories for seven years.

The endgame: developing medications that can bolster a child’s microbiome to improve their overall health.

We want to come up with a product that can work for every baby, no matter how they’re born, no matter how they’re fed,” Culler said. “We want them to have the right microbes for health success.”

Before that happens, Persephone has to recruit more parents to send infant poop.

“The sooner we can get the poop, the sooner we can get the product,” Culler said.

Persephone Biosciences just raised $15 million in seed financing. The company hopes that the return on investment will be a healthy gut for kids and a healthy financial return. People who wish to donate should go to