Current industrial practice in solid state fermentations for secondary metabolite production: the Biocon India experience

Solid substrate fermentation at Biocon was originally envisaged for the production of enzymes, used in the food processing industry. The original process developed at Biocon was a hygienically designed automated tray culture process. Plants using this process still continue to run effectively at Biocon, and produce a variety of products meeting and exceeding FCC/JECFA specifications for food products. Biocon recently designed, developed and patented a new bioreactor, the PlaFractor™ (pronounced play-fractor) for carrying out fermentations that use solid matrices—a term covering both nutritive support matrices as well as non-nutritive matrices impregnated with medium. Using the PlaFractor™ process it is now possible to extend the use of solid matrix fermentation for the production of enzymes, biocontrol agents and pharmaceutical products, that require elaborate containment—under precisely defined conditions. The production takes place in computer controlled bioreactors, using complex fermentation control algorithms. All the operations of solid matrix fermentation, i.e. sterilization, cooling, inoculation, fermentation and process control, product recovery and post-fermentation sterilization, are all done in one single equipment, which was not hitherto possible. All the advantages of traditional solid state fermentation, over submerged fermentation, like low energy consumption, low water requirement, high mass transfer coefficient, no foaming, and high product concentrations are retained. In addition, techniques that are important to submerged fermentation, like fed-batch fermentation, process parameter profiling, air and media sterilization, operation under aseptic environments, and ease of handling, can now be easily applied to solid state fermentation, because of the way this bioreactor is designed. A production plant, built around this bioreactor has already been operating for more than a year.