Decarboxylation of Amino Acids + Ornithine Decarboxylase

Basic Goal

test whether bacteria can decarboxylate certain amino acids

pH indicator

bromocresol purple

Process

Bacteria is added to medium containing certain amino acid, and if amino acids are decarboxylated then amines will be produced which makes pH alkaline

Positive

Purple color = decarboxylase + for amino acid

Negaitve

Yellow color

Ornithine Decarboxylase Test Goal

To identify Proteus (+), and differentiate Klebsiella (-) from Serratia and Enterobacter (+)

Process

Bacteria are added to a purple medium, so only negative results will see a color change. The decarboxylation of ornithine will release amines making the medium alkaline

Positive

Medium remains purple = OD +

Negative