Longer version of the video here: https://rumble.com/v1wz688-david-straight-out-of-babylon-excerpt-chernobyl-super-immune-system-and-can.html

The scientist the speaker refers to is Lawrence Royce @ Kentucky State University. I think (not positive) that his company is seed.com.

They have a rather expensive probiotic ($50/month, subscription only) although it's well reviewed and there's an enormous amount of scientific data posted on the site.

There is definitely some peer reviewed data out there pointing to the strain referenced in the video (lactobacillus salivarius) as a potential anti-cancer agent for some cancers.

Still researching but this is what I've found so far.