Evidence for an Unidentified Growth Factor Required by Microbacterium flavutn ∗

Abstract

Summary

Micro bacterium flavum has been shown to require an unidentified factor(s) and magnesium for optimal growth in a synthetic medium. The addition of this substance to an otherwise synthetic medium supports growth approximately equivalent to that obtained in Difco Micro Inoculum Broth or trypticase soy broth. The unidentified factor(s) can be found in Wilson's liver L, asparagus juice, yeast extract, soybean meal, and Alpha protein. It is not replaceable by any known growth factors tested. It is stable to HCl hydrolysis, treatment with HNO₂ and H₂O₂ and is separated from aqueous solution with acetone.