What indicator is used in Lipase Agar to indicate hydrolysis?

The correct answer, Spirit Blue, is used in Lipase Agar to indicate hydrolysis because it is a dye that changes color in response to the presence of fatty acids released during the hydrolysis of lipids. When lipase enzymes secreted by bacteria break down lipids present in the medium, the fatty acids produced cause the Spirit Blue dye to become more intense in color, indicating positive lipolytic activity. This visual cue allows researchers to easily assess the ability of microorganisms to produce lipase and thus their capacity to hydrolyze lipids.

Bromothymol blue, phenol red, and litmus are indicators used in different types of media to detect changes in pH or other biochemical processes, but they are not specifically tailored to respond to lipase activity in Lipase Agar. Therefore, Spirit Blue stands out as the appropriate indicator for this particular application.