INTERACTION OF CYSTINE AND CASEIN HYDROLYSATE DURING THE AUTOCLAVING OF A MICROBIOLOGICAL ASSAY MEDIUM

Abstract

The limitation to acid production by Lactobacillus arabinosus (ATCC 8014) occasioned by separate autoclaving of glucose was shown to involve an interaction of cystine with casein hydrolysate. Cystine thus became the limiting factor. Autoclaving in the presence of glucose prevented cystine loss. The inhibition did not occur in filter sterilized media and could be prevented in autoclaved media by adding extra cystine to the glucose soln. prior to its separate sterilization in the autoclave and by addition of cysteine aseptically to the autoclaved medium.