---
title: Ammonium Sulfate (saturated)
description: "Saturated ammonium sulfate is a reagent used to determine the production of the enzyme gelatinase.  The gelatinase test is performed by streaking the microbe being tested on an agar medium containing 3% gelatin and allowing the culture to grow overnight.…"
url: "https://vumicro.com/docs/ammonium-sulfate-saturated-todo/"
updated: "2022-08-01"
category: Reference Library / Reagents, Chemicals, Stains
---

# Ammonium Sulfate (saturated)

Saturated ammonium sulfate is a reagent used to determine the production of the enzyme gelatinase.  The gelatinase test is performed by streaking the microbe being tested on an agar medium containing 3% gelatin and allowing the culture to grow overnight. About 5 ml of ammonium sulfate is then used to flood the plate, where it reacts with gelatin in the medium to produce a cloudy precipitate.  When gelatin has been digested by the enzyme gelatinase, the region around a colony will be gelatin-free and will lack the cloudiness found elsewhere in the agar.  This will result in a clear halo surrounding the colony for a positive test for gelatinase.