Reading the paper (paywalled, unfortunately), it seems that the big breakthrough was not that a microbe can degrade polyurethane (there's almost a dozen other citations), but that this one can do it both aerobically and anaerobically. That means that you can introduce it to a dump, and it will work in both the deep and surface layers.
The discovery here is an endophytic (living in a plant) fungus that can grow anaerobically, using polyurethane as its sole carbon source.
The authors suggest fungi that digest polyurethane have been known for decades. ("""Enzymatic degradation of PUR has been demonstrated by both fungi (4, 5, 6, 19) and bacteria (14, 17, 23).""")
They cite one reference from 1968, which itself implies polyurethane-degrading fungi had been known long before then:
[1]http://aem.asm.org/content/77/17/6076.abstract