This biochemical assay determines the ability of a microorganism to produce the enzyme lysine decarboxylase. The enzyme removes the carboxyl group from the amino acid lysine, producing cadaverine and carbon dioxide. A positive result is typically indicated by a color change in the growth medium from yellow to purple, reflecting an alkaline pH shift caused by the accumulation of cadaverine. A negative result is indicated by a yellow color, meaning no decarboxylation has occurred.
Differentiating bacterial species is crucial for accurate identification in clinical, research, and industrial settings. This specific assay provides valuable information for distinguishing enterobacteria and other gram-negative bacilli, particularly in scenarios where phenotypic characteristics overlap. Its historical significance lies in offering a relatively simple and cost-effective method for microbial classification, contributing to a deeper understanding of bacterial metabolism and diversity.
