Department of Chemical Engineering, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.
Biotechnol Bioeng. 1989 Sep;34(6):731-40. doi: 10.1002/bit.260340602.
The influence of Aspergillus niger broth rheology, bioreactor geometry, and superficial gas velocity on the volumetric liquid phase oxygen transfer coefficient (k(L)a(L)), riser gas holdup (epsilon(GR)), and circulating liquid velocity (u(LR)) was studied in a bubble column (BC) and two external-circulation-loop airlift (ECLAL) bioreactors. The results are compared to those of previous studies on homogeneous fluids and in particular with a recent study on non-Newtonian carboxymethylcellulose (CMC) solutions conducted in the same contactors used for the A. niger fermentations. As expected from the CMC-based studies, in the heterogeneous broths of A. niger epsilon(GR), k(L)a(L), and u(LR) decreased with increasing broth apparent viscosity; epsilon(GR) and k(L)a(L) decreased with increasing downcomer-to-riser cross-sectional area ratio, A(d)/A(r), whereas u(LR) increased with increasing A(d)/A(r). Gas holdup data in the airlift fermentations of A. niger were well predicted by the CMC-based correlation. However, the CMC-based correlations produced conservative estimations of k(L)a(L) and overestimates of u(LR) compared to the observed values in the A. niger broths.
黑曲霉菌浆流变学、生物反应器几何形状和表气速对体积液相氧转移系数（k（L）a（L））、升气管气含率（ε（GR））和循环液速（u（LR））的影响在鼓泡塔（BC）和两个外循环环空升流（ECLAL）生物反应器中进行了研究。结果与以前对均相流体的研究进行了比较，特别是与最近在相同的接触器中进行的非牛顿羧甲基纤维素（CMC）溶液的研究进行了比较，用于黑曲霉发酵。如基于 CMC 的研究预期的那样，在黑曲霉的异质菌浆中，ε（GR）、k（L）a（L）和 u（LR）随菌浆表观粘度的增加而降低；ε（GR）和 k（L）a（L）随降液管与升气管横截面积比 A（d）/A（r）的增加而降低，而 u（LR）随 A（d）/A（r）的增加而增加。黑曲霉气升式发酵中的气含率数据很好地预测了基于 CMC 的相关性。然而，与黑曲霉菌浆中的观察值相比，基于 CMC 的相关性对 k（L）a（L）的估计保守，对 u（LR）的估计过高。
