ISSN:
0006-3592
Keywords:
Aspergillus awamori
;
intrinsic kinetic parameters
;
oxygen concentration profiles
;
oxygen microelectrode
;
immobilisation
;
pellet formation
;
Chemistry
;
Biochemistry and Biotechnology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Fungi like Aspergillus awamori may spontaneously form pellets, which introduces an extra oxygen transfer resistance and influences the activity of the microorganism. Consequently, dramatic variations of apparent kinetics are reported in literature, due to variations in culture conditions, e.g., oxygen bulk concentration and pellet morphology. True intrinsic growth parameters like maximum growth rate and biomass yield, are important for process modelling and design. Values for these parameters may be obtained from observed kinetics by properly accounting for the anaerobic activity of the fungus. The true aerobic carbon yield for A. awamori of 0.6 mol Cx/mol Cs could be determined from the observed biomass yield after macroscopic monitoring of the anaerobic activity, and correction for the ethanol production by the fungal pellets. The true maximum growth rate was obtained from artificially immobilised A. awamori. In such well-defined system, transport is only diffusive and the morphology is not influenced by the stirring conditions. A maximum growth rate of 0.4 h-1 at pH 4.5 could be established in gel beads after microscopic monitoring of the oxygen penetration with microelectrodes. The developing biomass concentration profiles in these beads may be inferred from an adequate theoretical description of the oxygen profiles in course of time. © 1998 John Wiley & Sons, Inc. Biotechnol Bioeng 58: 478-485, 1998.
Additional Material:
9 Ill.
Type of Medium:
Electronic Resource
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