I'm curious as to what the bacteria are actually eating and as to the specifics of his process, but the results are definitely pretty interesting.
Bacteria will eat damn near anything. One of the biggest problems with buying lenses from the pacific rim is the fungus that actually eats the glue used to make multi-element lenses. And yes, fungus isn't bacteria. Just sayin'. Photographic film is generally comprised of multiple layers of chemicals sensitive to different bands of light. Print film is usually red, green and blue. Good print film is red, green, cyan and blue. Ektachrome, a slide film, was four layers of chemicals that required wicked bad processing; Velvia had 27 different layers. I reckon the bacteria are eating the binders betwixt the layers.