Continuous production of daidzein and genistein from soybean in a magnetofluidized bed bioreactor

A magnetofluidized bed (MFB) bioreactor has been used for continuous production of daidzein and genistein from immobilized soybean culture for over 2 months. The MFB, which offers continuous, plug-flow biocatalyst throughput, is well suited for production of intracellularly stored plant metabolites. Soybean cultures were co-immobilized with ferritic stainless steel in calcium alginate spheres. Transport of biocatalyst through the column was controlled with a magnetic valve. Immobilized soybean concentrations reached over 10 g of dry tissue/L of biocatalyst. Daidzein and genistein concentrations ranged from 10 to 200 mu g/g of dry soybean tissue. Biocatalyst microscopy suggested that oxygen diffusion in the biocatalyst was not rate limiting. Ampicillin, Timentin, and Benlate were found to have limited phytotoxicity at concentrations useful in preventing contamination in long-term, continuous bioreactor operation.