Continuous ethanol production byZymomonas mobilisin a fluidized bed reactor. Part I. Kinetic studies of immobilization in macroporous glass beads

✍ Scribed by D. Weuster-Botz

• Publisher: Springer
• Year: 1993
• Tongue: English
• Weight: 610 KB
• Volume: 39
• Category: Article
• ISSN: 1432-0614
• DOI: 10.1007/bf00164449

✦ Synopsis

A model has been developed to calculate the ethanol production in a well-mixed fluidized bed reactor. This model takes into account diffusion and the reaction inside porous glass beads and the activity of suspended cells in the fluidized bed reactor. The associated model parameters have been determined from the literature and by kinetic studies with Z y m o m o n a s mobilis in a continuous stirred tank reactor. The model permits g o o d predictions of steady-state data in a fluidized bed reactor at residence times longer than 1-1.5 h. The immobilization of Z . mobilis in a fluidized bed reactor results in high ethanol space-time yields of more than 50 g . 1 -1 . h -1 at a glucose conversion of 80% (glucose in substrate: 120 g 1-1). A t 99% conversion a space-time yield of 30 g . l -l . h -1 can be achieved when two fluidized bed reactors operate as cascade.

immobilization techniques, substrates, reactor configurations) are varied.

This paper deals with experimental steady-state studies of continuous ethanol production by Z. mobilis immobilized in macroporous glass beads in a wellmixed fluidized bed reactor. A model to predict the ethanol production in such fluidized bed reactors is developed. This model describes the effects of diffusion inside the macroporous glass beads on the reaction rate. In contrast to the literature (e.g., Vos et al. 1990) the activity of suspended cells in the fluidized bed reactor is also considered. The parameters of this model were obtained from the literature and by kinetic studies with Z. mobilis in continuous stirred tank reactor (CSTR). The kinetic model considers product and substrate inhibition as well as maintenance energy effects.