OBSERVATIONS ON THE GROWTH OF YEASTS IN PURE NUTRIENT SOLUTIONS

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Abstract
In a study of the growth of various yeasts in synthetic media, 46 strains were used in the earlier work, and 6 of these were studied in later work. After weekly transfers in a synthetic medium for 28 weeks, 26 cultures of the 46 were still alive, 22 of these showing abundant growth; in the same medium without NaCl, 24 cultures lived, 16 showing abundant growth. Four strains apparently required NaCl, as they failed in the medium without it. Wildier''s "bios" was found to be absent from Merck''s "highest purity" saccharose. Aeration resulted in maximum cell counts of 3-15 times those of unaerated controls. Erythrosin (0.5 gm. in 100 cc. of water) was a better stain for distinguishing living from dead cells than methylene-blue (1:1000 and 1:200) or eosin (1:200). After preliminary experiments, the following synthetic medium was adopted (the figures being in gm.): sucrose 100.0, NH4Cl 1.2, K2HPO4 0.5, CaCl2 0.1, MgSO4 0.2, distilled water 1000.