The single reference I could find in the rules related to assigning enzyme on a Refugium is rule E1.
"Biont Target. You can only assign Bionts and Enzymes to Refugia in the home row (E2) of one of your organism or in an active row (D2)"
My understanding is that you can assign an enzyme on a Refugium if its row is active. But, if the row is inactive, to be allowed to assign an enzyme to a Refugium, you need to have an organism (in your tableau) which belongs to the same landform row.
However, example of play J3 shows that on an inactive row, an enzyme is assigned on a Refugium where there is a Biont (at that stage, the player doesn't have any organism in his tableau).
I'm confused. I would appreciate a clarification.
Sorry about that. We playtested that your Biont's presence in a landform row allowed you to operate there, even if it is inactive. Accordingly E1 should read:
• Biont Target. You can only assign Bionts and Enzymes to Refugia in an active row (D2), or in a row where you have a Biont, either in a Refugium or in an Organism with that home row (E2).