Production of gibberellic acid by fermentation.

The elonigationi of rice plants iinduced by the application of cell-free culture filtrates from the li(uid culture of Futsariutm moniliforme was first demonstrated in 1926 by Kurosawa. Twelve years later, Yabuta and Sumiki (1938) were able to isolate in crystalline form two growth-promotinig compounds, gibberellins A and B, from filtrates of this organism; gibberellin A was the maini substaniee obtained. In 1954, Curtis and Cross reported the discovery of a third metabolite, gibberellic acid, from a culture filtrate of Gibberella fuijikuroi, the perfect stage of F. moniliforme. This finding was con1firmed the followinig year by Stodola et al. (1955) and Takahashi et al. (1955). Brian anid Grove (1957) have writteni anl excellent comprehensive review of the gibberellins with emphasis placed upon gibberellic acid. It is this compounid with which we are concerned at this time. A complete literature review has been prepared by Stodola (1958). The straini of Fuisariuim m9niliformestraini Kewno.917, which we used for these investigational studies, was the one reported by Borrow et al. (1955) to give the highest yield of gibberellic acid. With this culture and a medium composed of glucose, 40 g per L; ammonium tartrate, 9.5 g per L; moniopotassium phosphate, 2.0 g per L; potassium sulfate, 0.6 g per L; and magnesium sulfate, 0.2 g per L; they obtained 180 mg per L gibberellic acid. The yields obtained by Borrow et al. in a medium used by Yabuta, Sumiki, and Uno (1939) consisting of glycerol or glucose, ammonium chloride, and monopotassium phosphate were negligible with all of the Kew cultures. The former value of 180 mg per L gibberellic acid is substantially greater than that of 22 mg per L reported by Stodola et al. (1955) in a medium consisting of glucose, 15 g per L; monopotassium phosphate, 3 g per L; ammoniium chloride, 3 g per L; land magniesium sulfate, 3 g per L. Usinig the Kewv no. 917 culture we obtained gibberellic acid yields of 880 mg per L in shaker flasks anid 650 mg per L in 1000-gallon fermentors.