Growth Factors for Bacteria

Abstract

Accessory growth-promoting substances for Clostridium butylicum and Cl. aceto-butylicum have been found in liver, yeast, malt sprouts, yellow corn, wheat bran, and a commercial vitamin preparation (Vitab II). Growth was measured by either rate of sugar fermentation or turbidity (Evelyn photometer). Considerable purification of the stimulatory substance was accomplished by extraction with ether from acidic soln., after a preliminary extraction with ether from neutral soln. to remove inactive substances. The active material was completely adsorbed on norit but could not be completely eluted with alcohol and pyridine. Alcohol-soluble Cu salts gave detectable stimulation at a conc. of 0.01 [gamma] per ml. and maximum effect at 1 [gamma] per ml. The factor cannot be replaced by riboflavin, indol acetic acid, sporo-genes growth factor, nicotinic acid amide, vitamin B1, vitamin B6, pimelic acid, inositol, [beta]-alanine, pantothenic acid, or by a mixture of all the naturally occurring amino acids except hydroxy-glutamic acid. It is stable to auto-claving, to steaming in normal alkali and to bromination.