Determination of the average shear rate in a stirred and aerated tank bioreactor

Author(s)

Campesi, Alexandre ^[1] ; Cerri, Marcel O. ^[1] ; Hokka, Carlos 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. 32, n. 2, p. 241-248, FEB 2009.
• Web of Science Citations: 21

Abstract

A method for evaluating the average shear rate ((gamma) over dot(av)) in a stirred and aerated tank bioreactor has been proposed for non-Newtonian fluids. The volumetric oxygen transfer coefficient (k(L)a) was chosen as the appropriate characteristic parameter to evaluate the average shear rate ((gamma) over dot(av)). The correlations for the average shear rate as a function of N and rheological properties of the fluid (K and n) were obtained for two airflow rate conditions (phi(air)). The shear rate values estimated by the proposed methodology lay within the range of the 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 0.5 vvm and four different rotational impeller speeds. The results show that the values of the average shear rate ((gamma) over dot(av)) varied from 437 to 2,693 s(-1) by increasing with N and flow index (n) and decreasing with the fluid consistency index (K). (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