Ropiness from pedio usually takes quite awhile to develop in beer - pedio is a slow mutha, especially if its an infection (not a cultured pitch).
Maybe the WL lacto strain can produce ropiness? Take a look at Wild Brews. I know it can produce a kind-of-pellicle, so that may be what you're seeing. I've only used the Wyeast culture, but I understand the WL version to be more akin to what you can culture from grain.
Side note: This is an awesome biology project. High School? Is he using Wild Brews as a reference?