Abstract: The present invention provides biosensors and methods of use for detecting the presence or absence of mycoplasma contamination through the detection of hydrolytic enzymes that are conserved among Mycoplasma species. Such hydrolytic enzymes include, but are not limited to, proteases, reductases and nucleases.

Abstract: A device and method for detecting the presence or absence of a prokaryotic microorganism are provided, comprising the steps of identifying a protein, such as a microbial-specific protease that characterizes the presence of a specific prokaryotic microbe and thereby provides a marker for that microbe; detecting the protease that is a marker for the presence of a specific prokaryotic microbe by cleaving a substrate when the protease is present; and signaling the presence of that protease when cleavage has occurred. More specifically, the method comprises identifying at least one outer membrane protein or a secreted protein that is unique to a particular microbial pathogen such as for example Listeria monocytogenes and that is substrate specific.