What color indicates a negative enzymatic hydrolysis result in a Tween 80 test?

In the Tween 80 test, which is used to identify the ability of bacteria to hydrolyze Tween 80 (a polysorbate), the color indication is crucial for interpreting the results. A negative enzymatic hydrolysis result is indicated by an amber color. This occurs because, when Tween 80 is not hydrolyzed by the bacteria, there are no changes in the chemical structure of the substrate that would lead to a color change.

The amber color specifically signals the absence of hydrolysis products, confirming that the bacteria tested lack the enzyme required to break down Tween 80. This test is particularly important for differentiating certain bacterial species based on their enzymatic capabilities, which can aid in identification and classification within clinical or environmental microbiology contexts.