Novel method for the preparation of sterile collagen-agarose-plates for isolating collagenolytic bacteria.

An assay method for bacterial collagenase using sterile collagen-agarose plates was developed to isolate collagenolytic bacteria. In order to avoid heat-denaturation of collagen, the plates were made at 37 degrees C mixing microwave-sterilized collagen with low melting point-agarose. Sensitivities to various proteases were tested on the plates; it was shown that whereas the collagen in these plates was digested only by the collagenases, the collagen could also be hydrolyzed by other proteolytic enzymes if it had been either sterilized by ethylene oxide or solidified with conventional agar at a higher temperature. Colonies of Clostridium histolyticum cells grown on the plates had clear zones around them and their collagenase activities could be readily detected.