Another version of enzyme cleaner we've used with good results is Simple Solution, available in pet stores in small bottles or by the gallon.It also did not set off my perfume allergies.
Have you checked for hemp matting? In the 60's, my family had an old car that developed an incredible stink. It turned out that underneath the flooring was hemp matting as a pad, which had somehow gotten wet.Like old carpeting, the best idea is to rip it out.