PRODUCTION OF GIBBERELLINS FROM (-)-KAURENE WITH A BIO-REACTOR BY MICROBIAL CONVERSION WITH GIBBERELLA-FUJIKUROI

Gibberellins could be produced with a bio-reactor in a large yield by the microbial conversion of (-) -kaurene isolated from sugi (Cryptomer ia japonica D. Don) leaves in a mycelium suspension of the two strains of Gibberella fujikuroi IFO 30337 and 31251, with a minor amount of g rowth regulator. The regulator used was amoxy)-5-isopropyl-2-methylphe nyltrimethylammonium chloride. In the case of G.fujikuroi IFO 30337, t he amounts of the gibberellins produced by the microbial conversion of (-) -kaurene in the substrate concentration of 0.01% of the culture m edium increased with the extension of incubation time, and reached the maximum yield after incubation for ten days. The yield was 54% of the (-) -kaurene. However, when the incubation was conducted with the sam e strain in the substrate concentration of 0.1%, the maximum yield was 9.3% of the (-) -kaurene. On the contrary, in the case of G. fujikuro i IFO 31251, the maximum yield of the gibberellins from (-) -kaurene w as obtained when the incubation was for three days with the substrate concentration of 0.01%. The yield was 39% of (-)-kaurene. The amount o f gibberellins produced with G. fujikuroi without the substrate and th e growth regulator was about one-twentieth, compared with that with th e substrate and the growth regulator. To increase the amounts of the g ibberellins produced by the microbial conversion of (-) -kaurene, vari ous incubation conditions were examined with the use of G. fujikuroi I FO 31251. However, the increase in the amounts was only about 5%. Acti vities of the gibberellins produced from (-)-kaurene by dwarf rice mic rodrop assay using tan-ginbouzu were measured. The activities of the g ibberellins from (-) -kaurene were greater than those of gibberellin-A 3 (GA3) and GA4, one of the greatly active gibberellins in plants.