Steady and dynamic shear characterization of cellulase-producing Trichoderma reesei suspensions

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:150419

Marten, M R; Velkovska, S; Khan, S A ^[1]

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1. North Carolina State Univ., Raleigh, NC (United States); and others

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 cellulose 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.

• Research Organization: Oak Ridge National Lab., TN (United States)
• OSTI ID: 150419
• Report Number(s): CONF-940526--
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
BIOCONVERSION
BIOMASS
CELLULASE
CELLULOSE
FERMENTATION
GROWTH
MASS TRANSFER
RHEOLOGY
SUBSTRATES
SUSPENSIONS
TRICHODERMA
VISCOSITY
XYLOSE