Selective production of bikaverin in a fluidized bioreactor with immobilized Gibberella fujikuroi

Abstract

The best culture medium composition for the production of bikaverin by Gibberella fujikuroi in shake-flasks, i.e. 100 g glucose l⁻¹; 1 g NH₄Cl l⁻¹; 2 g rice flour l⁻¹; 5 g KH₂PO₄ l⁻¹ and 2.5 g MgSO₄ l⁻¹, was obtained through a fractional factorial design and then scaled-up to a fluidized bioreactor. The effects of carbon and nitrogen concentrations, inoculum size, aeration, flow rate and bead sizes on batch bikaverin production using immobilized G. fujikuroi in a fluidized bioreactor were determined by an orthogonal experimental design. Concentrations of up to 6.83 g bikaverin l⁻¹ were obtained when the medium contained 100 g glucose l⁻¹ and 1 g NH₄Cl l⁻¹ with an inoculum ratio of 10% v/v, an aeration rate of 3 volumes of air per volume of medium min⁻¹, and a bead size of 3 mm. Based on dry weight, the bikaverin production was 30–100 times larger than found in submerged culture and approximately three times larger than reported for solid substrate fermentation.