NUTRIENT-REQUIREMENTS OF RENIBACTERIUM-SALMONINARUM ON AGAR AND IN BROTH MEDIA

In well-aerated broth cultures, good growth of Renibacterium salnwnina rum was obtained in a serum-free medium consisting of 1% peptone, 1% y east extract, and 0.1% L-cysteine (PYC broth). In contrast, serum or c harcoal is required for growth on agar medium. Charcoal treatment of b roth media, either before bacterial inoculation or during growth, incr eased the growth of R. salmoninarum, whereas the surfactants Tween 20 and Tween 80 inhibited growth. L-Cysteine was essential for optimal gr owth. Other organic sulfur compounds, such as D-cysteine, L-methionine , homocysteine, homocysteine thiolactone, and reduced glutathione, sup ported only lower levels of growth, while cystine and dithiothreitol d id not allow growth.