Use of gas chromatography for detecting ornithine and lysine decarboxylase activity in bacteria

A gas-liquid chromatography (GLC) procedure for the detection of L-ornithine and L-lysine decarboxylase (EC 4.1.1.17 and EC 4.1.1.18, respectively) activities of bacteria was developed and evaluated against Møller's method, a conventional biochemical test. Cultures were incubated for 2 to 4 h in a simple growth medium and tested by GLC for putrescine and cadaverine, the direct decarboxylation products of ornithine and lysine, respectively. Results obtained with various Enterobacteriaceae, pseudomonads, and vibrios showed that the GLC procedure was superior to the conventional test; clear, well-defined results were obtained within 3 to 5 h, even with cultures which gave weak, delayed, or variable reactions by Møller's method. This GLC procedure for the determination of decarboxylase reactions would be useful in microbiological laboratories for culture identification and for various other enzymatic studies.