We're definitely talking about enzymatic cleavage in this instance. I'm sure Momenta uses both chemical and enzymatic cleavage.
For Lovenox, specifically, MNTA uses only chemical cleavage, and Wheeler himself has confirmed this. For various other compounds MNTA may be developing, we may presume that both chemical and enzymatic cleavage come into play.
The patent awarded today has broader applicability than just Lovenox and heparin-based drugs.