Gibberellic Acid Production by Different Fermentation Systems Using Citric Pulp as Substrate/Support

Gibberellic acid (GA₃) is an important phytohormone, a member of gibberellins family, which acts as a promoter and regulator of plant growth. This study aimed to evaluate GA₃ production by Fusarium moniliforme LPB03 and Gibberella fujikuroi LPB06 using different techniques of fermentation, solid state fermentation (SSF), submerged fermentation (SmF), and semisolid state fermentation (SSSF), and different types of bioreactors. In all techniques, citric pulp (CP), a subproduct obtained from the extraction of orange juice, was employed as the substrate/support. GA₃ production by SSF reached 7.60 g kg^-1 and 7.34 g kg^-1 in Erlenmeyer flasks and column bioreactors, respectively. For SmF, the highest concentration of GA₃ obtained was 236.00 mg L^-1 in Erlenmeyer flasks, 273.00 mg L^-1 in a 10 L stirred tank reactor (STR), and 203.00 mg L^-1 in a 1.5 L bubble column reactor (BCR). SSSF was conducted with a CP suspension. In this case, GA₃ concentration reached 331.00 mg L^-1 in Erlenmeyer flasks and 208 mg L^-1 in a BCR. The choice of the fermentation technique is undoubtedly linked to the characteristics and productivity of each process. The methods studied are inexpensive and were found to produce good proportions of GA₃, making them suitable for several applications.