Average shear rate in three pneumatic bioreactors

Author(s)

Thomasi, Sergio S. ^[1] ; Cerri, Marcel O. ^[1] ; Badino, Alberto C. ^[1]

Affiliation

^[1] Univ Fed Sao Carlos, Dept Chem Engn, BR-13565905 Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: Bioprocess and Biosystems Engineering; v. 33, n. 8, p. 979-988, OCT 2010.
• Web of Science Citations: 11

Abstract

A method proposed in recent literature was applied to evaluate the average shear rate ((gamma) over dot(av)) in three pneumatic bioreactors of 5-dm(3) working volume: bubble column, split airlift, and concentric-tube airlift. The volumetric oxygen transfer coefficient (k(L)a) is the appropriate characteristic parameter to assess the average shear rate (gamma) over dot(av) in this methodology. Correlations for (gamma) over dot(av) as a function of superficial gas velocity in the riser region (U(GR)) and rheological fluid properties (consistency index, K, and flow index, n) were obtained for each model of pneumatic bioreactor studied. The (gamma) over dot(av) values estimated by the proposed methodology lay within the range of values calculated by classical correlations. The proposed correlations were utilized to predict the (gamma) over dot(av) during the Streptomyces clavuligerus cultivations carried out at the same specific air flow rate (3.5 vvm) in the different types of pneumatic bioreactors. The lowest values of (gamma) over dot(av) related to the highest values of consistency index (K) were found for the bubble column bioreactor, and the highest values of (gamma) over dot(av) related to the lowest values of K were found for the concentric-tube airlift bioreactor. Intermediate values were found for the split airlift bioreactor. The results showed that high (gamma) over dot(av) values affect the structural health of the mycelia by the rupture of the hipha. (AU)

• FAPESP's process: 05/55079-4 - Production and purification of clavulanic acid, cephamycin C and other bioactive metabolites of Streptomyces
• Grantee: Carlos Osamu Hokka
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 08/10432-7 - Evaluation of the hydrodynamics and mass transfer of pneumatic reaction system and its utilization on production of beta-lactam compounds
• Grantee: Marcel Otavio Cerri
• Support Opportunities: Scholarships in Brazil - Post-Doctoral