A new NMR airlift bioreactor used in 31P-NMR studies of itaconic acid producing Aspergillus terreus.

An airlift bioreactor for in-vivo NMR studies of cells is described. The 10-mm diameter airlift reactor was constructed for studies of mycelial/pellet forming organisms, grown in suspension. With this device 161 MHz 31P-NMR spectra of living Aspergillus terreus cells, producing itaconic acid, have been obtained. Signals were observed for intra- and extracellular orthophosphate, glycerol-3-phosphorylethanolamine (GPE), glycerol-3-phosphorylcholine (GPC), sugar phosphates and polyphosphate. The spectra also showed broad overlapping resonances in the shift range of NAD(H) and NADP(H). Polyphosphate disappeared when the respiratory gas was exchanged for pure N2. The intracellular pH was estimated at 6.2. In spectra of cell extracts approx. 60 peaks were observed in the range of 20 to -22 ppm, and they confirmed the appearance of the metabolites observed in living cells.