Screening Plate Method for Detection of Bacterial β-Glucuronidase

For screening tests of bacterial beta-glucuronidase (EC 3.2.1.31) activity an agar plate (MUG plate) containing the enzyme substrate, 4-methylumbelliferyl-beta-D-glucuronide, was developed. In the presence of beta-glucuronidase, the strongly fluorescent 4-methylumbelliferone, which can be detected by ultraviolet light, was liberated. For tests of fastidious bacteria, the MUG-plate was enriched with supplements containing heat-labile growth factors without influencing the reaction. The plate was found to be suitable for screening tests. The sensitivity of the MUG-plate was determined by means of fluorimetric method. With the present method, beta-glucuronidase activities were demonstrated in some well-known beta-glucuronidae-producing microorganisms as well as in Bacteroides and Corynebacterium spp.