The microbiological assay of the vitamin B6 complex (pyridoxine, pyridoxal and pyridoxamine) with Kloeckera brevis

Abstract

A complete re-investigation of the microbiological assay of the vitamin B₆ complex (pyridoxine, pyridoxal and pyridoxamine) with the yeast Kloeckera brevis has been made. The superiority of the proposed method over others e.g., those involving Saccharomyces carlsbergensis 4228 (ATCC 9028), the protozoan Tetrahymena pyriformis and the X-ray mutant Neurospora sitophila 299, is discussed and suitable methods of extraction are described, particularly for blood, liver, human and rat brain, and urine.

Kloeckera brevis has also been found to be a more suitable organism for the cup-plate assay of the vitamin B₆ complex than S. carlsbergensis. The zones of exhibition are sharp and clear and background growth is reduced to a minimum, which is frequently not so with S. carlsbergensis.