Steady and dynamic shear characterization of cellulase-producing Trichoderma reesei suspensions
Suspension rheology of fungal fermentations is important in determination of mass transfer rates, as well as mixing quality. We have characterized Trichorderma reesei RUT-C30 suspension rheology during growth on xylose (soluble) and cellulose (particulate) substrates, using both steady and dynamic s...
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Veröffentlicht in: | Applied biochemistry and biotechnology 1995-09, Vol.51 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | Suspension rheology of fungal fermentations is important in determination of mass transfer rates, as well as mixing quality. We have characterized Trichorderma reesei RUT-C30 suspension rheology during growth on xylose (soluble) and cellulose (particulate) substrates, using both steady and dynamic shear measurements. Biomass growth was monophasic on xylose and biphasic on cellulose; the latter behavior is consistent with relatively rapid, early growth on soluble sugars derived from rapidly hydrolyzed material, followed by a second, slower growth phase owing to hydrolysis of more recalcitrant cellulose by increasing cellulase concentrations. Steady shear measurements established the presence of a yield stress for fermentation broths when using a 10 (vol)% fungal inoculum. The Casson equation represented all data well. Casson parameters of viscosity and yield stress followed biomass evolution: two maxima in both parameters were observed with cellulose substrates, and a single maximum with xylose. Dynamic shear measurements on broths indicated a gel behavior at small strains and a shear thinning liquid behavior at larger displacements. These results indicate the need to include rheology and mixing considerations in the subsequent development of a full biological and physical kinetic description of T. reesei cellulose conversions |
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ISSN: | 0273-2289 1559-0291 |
DOI: | 10.1007/BF02933435 |