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A new biomanufacturing platform combining intracellular metabolic engineering of the oleaginous yeastYarrowia lipolyticaand extracellular bioreaction engineering provides efficient bioconversion of plant oils/animal fats into high‐value products. However, predicting the hydrodynamics and mass transfer parameters is difficult due to the high agitation and sparging required to create dispersed oil droplets in an aqueous medium for efficient yeast fermentation. In the current study, commercial computational fluid dynamic (CFD) solver Ansys CFX coupled with the MUSIG model first predicts two‐phase system (oil/water and air/water) mixing dynamics and their particle size distributions. Then, a three‐phase model (oil, air, and water) utilizing dispersed air bubbles and a polydispersed oil phase was implemented to explore fermenter mixing, gas dispersion efficiency, and volumetric mass transfer coefficient estimations (k_La). The study analyzed the effect of the impeller type, agitation speed, and power input on the tank's flow field and revealed that upward‐pumping pitched blade impellers (PBI) in the top two positions (compared to Rushton‐type) provided advantageous oil phase homogeneity and similar estimatedk_Lavalues with reduced power. These results show good agreement with the experimental mixing andk_Ladata.

The development of gene therapies based on recombinant adeno‐associated viruses (rAAVs) has grown exponentially, so the current rAAV manufacturing platform needs to be more efficient to satisfy rising demands. Viral production exerts great demand on cellular substrates, energy, and machinery; therefore, viral production relies heavily on the physiology of the host cell. Transcriptomics, as a mechanism‐driven tool, was applied to identify significantly regulated pathways and to study cellular features of the host cell for supporting rAAV production. This study investigated the transcriptomic features of two cell lines cultured in their respective media by comparing viral‐producing cultures with non‐producing cultures over time in parental human embryonic kidney cells (HEK293). The results demonstrate that the innate immune response signaling pathways of host cells (e.g., RIG‐I‐like receptor signaling pathway, Toll‐like receptor signaling pathway, cytosolic DNA sensing pathway, JAK‐STAT signaling pathway) were significantly enriched and upregulated. This was accompanied by the host cellular stress responses, including endoplasmic reticulum stress, autophagy, and apoptosis in viral production. In contrast, fatty acid metabolism and neutral amino acid transport were downregulated in the late phase of viral production. Our transcriptomics analysis reveals the cell‐line independent signatures for rAAV production and serves as a significant reference for further studies targeting the productivity improvement in the future.

Previously, we identified six inhibitory metabolites (IMs) accumulating in Chinese hamster ovary (CHO) cultures using AMBIC 1.0 community reference medium that negatively impacted culture performance. The goal of the current study was to modify the medium to control IM accumulation through design of experiments (DOE). Initial over‐supplementation of precursor amino acids (AAs) by 100% to 200% in the culture medium revealed positive correlations between initial AA concentrations and IM levels. A screening design identified 5 AA targets, Lys, Ile, Trp, Leu, Arg, as key contributors to IMs. Response surface design analysis was used to reduce initial AA levels between 13% and 33%, and these were then evaluated in batch and fed‐batch cultures. Lowering AAs in basal and feed medium and reducing feed rate from 10% to 5% reduced inhibitory metabolites HICA and NAP by up to 50%, MSA by 30%, and CMP by 15%. These reductions were accompanied by a 13% to 40% improvement in peak viable cell densities and 7% to 50% enhancement in IgG production in batch and fed‐batch processes, respectively. This study demonstrates the value of tuning specific AA levels in reference basal and feed media using statistical design methodologies to lower problematic IMs.