Description and evaluation of reciprocating plate bioreactors

Wood Pulp as Model Fluid to Mimic the Oxygen Mass Transfer in Aspergillus Niger Fermentation

“…Increasing the intensity of agitation results in the production of smaller bubbles that have greater probability of being retained for a longer period of time in the bioreactor and thereby leading to an increase in gas holdup. Lounes et al (1995) have clearly shown that the gas holdup as a function of power input per unit volume also has two distinct regimes and similar threshold values.…”

“…The rheological properties of many fermentation media change during the course of the fermentation process due to the growth of microorganism and/or product formation. For example, in the case of pullulan production using Aureobasidium pullulans, the viscosity of the fermentation broth can Aureobasidium pullulans, the viscosity of the fermentation broth can Aureobasidium pullulans increase by many orders of magnitude during the course of fermentation because of the long water-soluble biopolymer chains that are synthesized (Lounes et al, 1995;Audet et al, 1996;Thibault and LeDuy, 1999). On the other hand, for fi lamentous microorganisms, the drastic increase in viscosity is associated with the growth and morphology of microorganisms.…”

“…Finding an optimum operating point for these parameters therefore becomes an important issue. For highly viscous fermentation broths, the use of traditional mixing devices such as Rushton turbines leads to non-uniform K L K L K a within the stirred tank a within the stirred tank a bioreactor (STB) (Lounes et al, 1995). It is usually large in the vicinity of the mixing element and signifi cantly lower further away.…”

“…Several unconventional mixing devices have been designed and studied. These are the reciprocating plate mixer (Lounes et al, 1995), the helical ribbon mixer (Jolicoeur et al, 1992), and the helical ribbon screw mixer (Tecante and Choplin, 1993). Helical ribbon mixers are good for mixing but relatively poor for oxygenation.…”

“…However, there are only few investigations considering their use as a gas-liquid contractor (Baird and Rama Rao, 1988). Lounes et al (1995) give a detailed description of this type of bioreactor. The reciprocating plates occupy the whole cross-sectional area of the bioreactor and, as a result, energy is imparted more gently and uniformly throughout the fermentation medium.…”