There are quite a few groups in academia working on bioreactor modeling in Fluent. I've been doing it at TU Delft focusing on Lagrangian biomass representation; indeed Jerome Morchain is doing highly interesting work using population balances to represent the biomass in an Eulerian fashion. Ralf Takors's group has done some Lagrangian work, and also did work on air-water mass transfer. In the fields of multiphase mass transfer and mixing in stirred tanks/bubble columns, you'll find tons of publications with too many groups to mention. The groups of Tiefeng Wang and Ning Yang in China are performing interesting work on gas-liquid flow representation. Also the work of Dale McClure in Australia is most interesting, treating aspects ranging from reaction kinetics to the effect of surfactants on bubble drag. All in all, there's a lot out there - so much to read it hardly leaves you time to do simulations yourself ;)