The problem is there is no evolutionary path to get to your enzyme catalyzed ecosystem. Enzymes don't appear out of nowhere, they evolve by chemical reactions. If you step back to earlier and earlier epochs you reach a point where the evolutionary path is dominated by non-catalyzed chemical reactions with typical pre-exponential factors and at 90K those reactions are turned off.
Chemical reaction rates drop by roughly 2x for every 10 degrees of cooling. Dropping from room temp (near 300 K) to the surface temp of Titan (90 K) would drop chemical reaction rates by roughly 2^21 or over a factor of 2 million. Arrhenius rates would drop even more dramatically. Chemical reactions used by life forms would be essentially turned off by this cold environment. Life could survive in hibernation mode, but it certainly could not thrive and reproduce.