Conference Presentation

PUBDB-2023-01302

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Controlling macromorphologies of Aspergillus niger during high and low shear stress bioreactor cultivation

Engelbert, K. ; Kheirkhah, T. ; Mueller, H.TUM* ; Deffur, C.TUM* ; Junne, S. ; Hammel, J.HZG*Hereon* ; Briesen, H. (Corresponding author)TUM* ; Neubauer, P. ; Meyer, V. (Corresponding author)

2023

Abstract: Submersed cultivation of filamentous fungi is widely used in fungal biotechnology. The formation of different macromorphologies, however, range from dispersed mycelia over loose clumps to dense pellets, and thus limits productivity with shear stress as one of the main influencing parameters. In this study, seed cultures with defined macromorphologies of the cell factory Aspergillus niger were exposed to high shear stress in stirred-tank (STR) and low shear stress in rocking-motion bioreactors (RMB). Talcum microparticles at 1 and 10 g L-1 were added to the seed cultures to achieve pellet populations with controlled diameter sizes. Physiological and morphological data were comprehensively investigated with high-throughput 2D image analysis and 3D synchrotron radiation based micro-computed tomography. This approach allowed us to determine the distribution of spore agglomerates, pellets and dispersed mycelia as well as hyphal densities and total hyphal lengths. Our data show that high shear stress in STR leads to breakage of pellets right after the stirrer was switched on. The mechanical stress from stirring also hindered pellets from surpassing a certain diameter during cultivation. In contrast, pellet size increased constantly until glucose was limited during RMB cultivations with largest macromorphological changes during the exponential growth phase. This work will allow us to estimate hyphal growth rates and pellet breakage as a function of shear stress for the first time and will furthermore pave the way for better understanding of cell-bioreactor interactions, and thus morphology-optimised cultivation processes.

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Contributing Institute(s):

1. DOOR-User (DOOR ; HAS-User)
2. Helmholtz-Zentrum Hereon (Hereon)
3. Technische Universität München (TUM)

Research Program(s):

1. 6G3 - PETRA III (DESY) (POF4-6G3) (POF4-6G3)
2. FS-Proposal: I-20211150 (I-20211150) (I-20211150)

Experiment(s):

1. PETRA Beamline P05 (PETRA III)

Appears in the scientific report 2023

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