An Egg-yolk Agar Diffusion Assay for Monitoring Phospholipase C in Cultures of Clostridium welchii

An egg-yolk agar diffusion assay of phospholipase C has been developed and investigated. The results demonstrate the necessity for strict control of the pH and volume of the egg-yolk agar and of the temperature and duration of incubation of the assay plates. The method has been used to monitor phospholipase C production in cultures of Clostridium welchii sparged continuously with CO₂ in N₂ and shows that maximal concentration occurs after ca. 6-8 h incubation at 37°C. The concentration falls slowly during subsequent anaerobic incubation supporting the opinion that Cl. welchii may elaborate a proteinase which destroys phospholipase C.