Can I safely pour grease followed by enzymes down a drain?
Absolutely not! Many people pour grease down a drain because there's this myth that you can pour enzymes behind it and everything will be hunky dory. Enzymes are designed for septic tanks and basically they are good bacteria. This bacteria consumes solid waste and keeps you from having to have your tank pumped more often than it should be.
On a side note, if your property is on city water and sewer, you're wasting your money pouring enzymes down your drain. They are meant for septic tanks only.
When you're using enzymes in a septic tank, they are flushed into that container and staying there, where they can grow and eat. The problem with pouring enzymes down a sink is that you're constantly using your sink. So the enzymes are never staying there. You flush them away.
Meanwhile the grease that was once liquid slowly hardens and causes a blockage in your drain.