THE EFFECT OF pH CONTROL IN THE AUTOCLAVING OF YEAST WITH RESPECT TO THE VITAMIN B FACTORS

Several investigators have described methods for the preparation of vitamin Bil concentrates practically devoid of vitamin Bz.~ However, very little has been reported on methods for procuring a rich source of vitamin B, free from vitamin B,. Salmon, Guerrant, and Hays (1) have described a preparation, made from velvet bean leaves, relying upon the specificity of fullers’ earth adsorption, solubility differences in alcohol, and heat. Smith and Hendrick (2), Sherman and Axtmayer (3), Chick and Roscoe (4), and other workers have relied upon autoclaved yeast to supply vitamin B,, and their results seemed to justify the opinion that by this procedure yeast could be consistently freed of vitamin B1 and still retain its vitamin Bz potency. Results in our laboratory with the use of autoclaved yeast have been sufficiently irregular to justify investigation of this practice, especially since we felt that a satisfactory test for vitamin B1 with rats necessitated a vitamin B-free diet plus a supply of vitamin Bt entirely free from vitamin Bi.