![]() The bottom test tube shows a gelatin medium after chilling that has a semi-solid state indicating that gelatin hydrolysis did not occur (gelatin hydrolysis negative). The top test tube shows a gelatin medium after chilling that has a more liquid form indicating that gelatin hydrolysis occurred (gelatin hydrolysis positive). Those species that do not hydrolyze gelatin will not have an effect on the gelatin and it will maintain its semi-solid state after chilling.įigure 1: Results from two gelatin hydrolysis tests. After incubation of the bacteria in the medium that hydrolyze gelatin, the medium will no longer form a semi-solid state, even after chilling. When bacteria that have this enzyme are inoculated into a nutrient medium containing gelatin, they will produce a gelatinase enzyme and break down the gelatin. To determine if a bacterial species hydrolyzes gelatin (and therefore has the a gelatinase gene and produces a gelatinase enzyme), the gelatin hydrolysis test is used. ![]() As such, the gelatin hydrolysis test is used to differentiate between bacteria that do and do not hydrolyze gelatin, and therefore is useful for characterizing and identifying bacterial species. Only those species of bacteria that do have a gelatinase gene are capable of producing a gelatinase and are capable of breaking down gelatin and using it as a nutrient source. Not all species of bacteria have a gene for a gelatinase enzyme. Gelatin hydrolysis test using the nutrient gelatin plate method. Therefore, it must first be broken down ( gelatin hydrolysis) by exoenzyme proteins called gelatinases. This test aids in the identification of Serratia, Pseudomonas, Flavobacterium and Clostridium. Gelatin provides a rich source of amino acids and peptides for bacteria, but its structure is too large to be transported inside the cell directly. The gelatin hydrolysis test detects the ability of bacteria to produce gelatinases. Use of gelatin is accomplished by the enzyme gelatinase. When chilled on ice, gelatin forms cross-links to itself to create a semi-solid state (gelatin makes Jello! have its unique form and texture). Pseudomonas aeruginosa (top), Escherichia coli (middle), and Serratia marcescens (bottom) were inoculated into nutrient gelatin agar. Gelatin Hydrolysis Test What is the purpose of the test The purpose is to see if the microbe can use the protein gelatin as a source of carbon and energy for growth. ![]() It tests the ability of the organism to produce gelatinase, a. ![]() Gelatin is a protein derived from collagen, a connective tissue of animals. A gelatin hydrolysis test is done for the biochemical identification of a micro-organism. ![]()
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