Kinetics and Transport Phenomena in Biological Reactor Design

Abstract

The application of chemical engineering principles is useful in an analysis of the design and operation of bioreactors. However, classical approaches to the analysis are limited by the following special constraints: 1.The reactant mixture is relatively complex. Microbial biomass increases with the biochemical transformation and catalyst is synthesized as the reactions proceed. 2.The bulk densities of suspended microbial cells and substrate particles generally approach those of their liquid environment so that relative flow between the dispersed and continuous phases is normall low. This situation may be conetrasted to the relatively heavy metallic catalyst particles generally used in chemical reactors. The sizes of single microbial cells are very small (in the range of a few microns) compared to chemical catalyst particles: coupled with the above constraints it is generally difficult to promote high velocities and turbulent-flows conditions 4.Polymeric substrates or metabolites and mycelial growth often produce very viscous reaction mixtures which are generally pseudoplastic non-Newtonian; again, these conditions tend to limit desirably high flow dynamics in bioreactors. 5.Many multicellular microbial growths, especially fungal ones generally form relatively large cell aggregates such as clumps or pellets: compared to catalyst particles,

Effects of shear rate, photoautotrophy and photoheterotrophy on production of biomass and pigments by Chlorella vulgaris

“…The likely reason for the higher cell growth rate and productivity of STR was its better gas–liquid oxygen transfer compared with the FPA. Mechanically agitated stirred tanks are generally known to be better in transferring oxygen from air to liquid than the nonmechanically mixed airlift bioreactors . As the observed photoheterotrophic growth was mainly due to heterotrophy, oxygen was required for consumption of glucose, the principal source of energy and carbon.…”

Influence of pectin, glucose, and pH on the production of endo- and exo-polygalacturonase by Aspergillus oryzae in liquid medium

“…The volumetric oxygen transfer coefficient (K L a) in non-inoculated WBE medium was determined using the static method described by Moo-Young and Blanch (1989). For this determination, the stirring speed was 300 rpm, the specific air flow rate was 2.0 vvm, and the medium temperature was held at 28 °C.…”

Ammonium Phosphate as a Sole Nutritional Supplement for the Fermentative Production of 2,3-Butanediol from Sugar Cane Juice

“…The temperature was kept at 37 °C and the pH was controlled at 5.5 with 5 m NaOH. The ini tial oxygen transfer coefficient (kLa), measured by the method reported by Moo-Young and Blanch (1987), was set at 95 h-1.…”