2-Naphthyl caprylate is a chromogenic substrate for carboxylesterase and lipase. 2-naphthol is released upon hydrolyzation. By simultaneous coupling with a diazonium salt, the corresponding azo-dye is formed.

Naphthols can also be detected by fluorescence analysis, and can be used in a colorimetric assay for the extracellular lipase of Pseudomonas fluorescent B52.

Used as a chromogenic substrate for N-Acetyl-β-D-galactosaminidase, yielding a blue precipitate. It is also used to detect Candida albicans.

6-Azauracil is a growth inhibitor effective on a variety of microorganisms. It functions by depleting the intracellular GTP and UTP nucleotide supply. 6-AU is research of transcription modulation.

Chenodeoxycholic acid is a bile acid found in humans, used for detergent purposes. Bile acids form micelles and break down lipids.

3-Indoxyl-β-D-glucuronic acid is used in detection and enumeration of E. coli. This chromogenic substrate is used for β-D-glucuronidase, and yields a blue precipitate upon cleavage.

H-Ala-pNAHCl is a substrate for L-alanine aminopeptidase, which is an enzyme that is localized in bacterial cell walls responsible for the cleavage of L-alanine from various peptides. Significant L-alanine aminopeptidase activity is specific to gram-negative microbes. Therefore, H-Ala-pNAHCl can be used in support of evidence that an organism is gram-positive or gram-negative. It is split by L-alanine aminopeptide into L-alanine and 4-nitroanine. The latter compound causes bacterial suspensions to turn yellow.

L-Malic acid, disodium salt is a dicarboxylic acid used to differentiate microorganisms based on their varying metabolic properties. It is a source of CO2 in the Calvin cycle and an intermediate of the citric acid cycle.