Cultivation of a filamentous mould in an airlift bioreactor

Abstract

Cephalosporin C biosynthesis was investigated in a pilot-plant external-loop airlift bioreactor for evaluating the capacity of this bioreactor to surpass the problems which arise from the morphology of the mould and the rheology of the broth.Some of the results were compared with those obtained in a stirred tank bioreactor.The dilution and the use of static mixers was necessary to overcome the effects of the high viscosities. The oxygen transfer rate represented 84% of that in the stirred bioreactor, but the efficiency of the power utilization was higher. The specific productivity of Cephalosporin C is comparable to that obtained in the stirred tank bioreactor, but the average specitic power consumption was found to be */3 of that in the stirred vessel.

Influence of Morphology on Product Formation in Aspergillusawamori during Submerged Fermentations

“…The batch medium contained the following components: MgSO 4 ‚7H 2 O 1.0 g/dm 3 , NaNO 3 6.0 g/dm 3 , KH 2 PO 4 1.0 g/dm 3 (all from Merck, Germany), yeast extract Kat 2.0 g/dm 3 (from Ohly, Germany), Antifoam 0.07 g/dm 3 (Structol, J673, Schill & Seilacher, Hamburg, Germany), and fructose 8.0 g/dm 3 (Boom, Meppel, The Netherlands). The feed had the following composition: xylose 53.0 g/dm 3 , fructose 20.0 g/dm 3 (Boom, Meppel, The Netherlands), yeast extract Kat 6.8 g/dm 3 (Ohly, Germany), and KH 2 PO 4 3.4 g/dm 3…”

“…Fermentation Conditions: The fermentations were performed in fermenters with a total volume of 20 dm 3 and a working volume of 7-8 dm 3 . The starting volume of the fermenter was 6 dm 3 .…”

“…Viscosity and cell differentiation in the mycelium will seriously influence the productivity obtained in submerged fungal fermentations. The viscous contribution will affect mass transfer and mixing properties (1,2), giving poor mass transfer and reduced mixing, which often results in lower productivity (3)(4)(5) and finally less economically attractive processes.…”

Interaction between CO2-mass transfer, light availability, and hydrodynamic stress in the growth ofPhaeodactylum tricornutum in a concentric tube airlift photobioreactor

“…One reactor configuration that can fulfill the demands of microalgae culture-i.e., high mass transfer, large ratio of surface-to-volume, ease of control, safe sterile operation and low mechanical forces on cells-is the airlift loop reactor. Airlift loop reactors have been applied to grow different types of cells and microorganisms (Ballica and Ryu, 1993;Fischer and Alfermann, 1995;Gavrilescu and Roman, 1995;Liu et al, 1996;Pollard et al, 1996;Zhang et al, 1995), but have rarely been used to grow microalgae (Gudin and Chaumont, 1991;Molina Grima et al, 1994b;Silva et al, 1987;Suzuki et al, 1995). Operational characteristics and the design features of airlift bioreactors have been treated in some detail by Chisti (1989).…”

Immobilization in Nanomatrices of Humicola Lutea Mycelium for Alpha-Galactosidase Biosynthesis in Laboratory Air-Lift Bioreactor

“…the use of nonmechanically agitated bioreactors for fungal cell fermentation may contribute to reducing the process costs, because they are considered to have a lower power requirement for comparable values of the oxygen mass transfer coefficient than the mechanically agitated vessels (17). The potential of such a device was previously demonstrated in the submerged cultivation of free as well as immobilized Humicola lutea cells (2,3,6) producing different hydrolyzing enzymes.…”