Fermentation monitoring by polymeric-resin-based microbiol assay.

A polymeric-resin-based microbiological assay is shown to yield results consistent with classical inhibition zone theory. This novel assay is applicable to cycloheximide, an antifungal antibiotic, at concentrations below 1.0 mug/mL and up to 800 mug/mL. Addition of ethanol to the cut-out wells of the assay plate helps to release the antibiotic and drastically increases the inhibition zone size. The antibiotic concentrations of both two component and multicomponent systems can be determined using this method. The use of polymeric-resin beads to monitor antibiotic concentrations is shown to be an effective technique for fermentation monitoring.