it´s equipment, i belive..
it dissolves the body -> no ninja-zombies
edit, upon googling Mortuary Enzymes i found this nice, long mc-story which contains a description of funcition..
http://sinai.critter.net/mutant/log.cgi?title=Breaking+Bad+News(....) The lab worker taps his fingers together. "I will start with your first question. And I will tell you thisshould not be shared lightly, as it is ... ah, sensitive information. Anyway, they are something of some small legend I have learned, those 'mortuary enzymes'. I believe Detective Kagetsume may be able to explain that part. They are ... what I have come to understand is a fail safe against certain agents from being captured alive, or their bodies found dead. They destroy the body. (.....)
edit2, upon checking the faq....
Page 146: Mortuary Enzymes
Q: Some units list “mortuary enzymes” as equipment but they aren’t on the list. What are they?
A: Mortuary enzymes instantly destroy dead remains, so they can’t be reanimated and used by the enemy. It works the same as the Carrion Enzyme Sprayer, except this item is personal. When a model equipped with these enzymes dies, the body instantly turns to dust, leaving no trace of their mortal remains.
cu