Tryptophan stimulation of growth and sporulation of Rhizopus arrhizus Fischer

Abstract

Individual amino acids (0.002 M) when added to Fothergill's medium stimulated the growth of Rhizopus arrhizus. Maximum growth was obtained with shikimic acid and the next highest growth with tryptophan. Sporulation was stimulated in the dark by the addition of tryptophan or methionine. Rhizopus arrhizus grown in tryptophan medium produced indoleacetic acid (IAA). The addition of IAA to Fothergill's medium did not increase the amount of growth and did not stimulate sporulation in the dark.