Biomass specific perfusion rate as a control lever for the continuous manufacturing of biosimilar monoclonal antibodies from CHO cell cultures.

Continuous manufacturing enables high volumetric productivities of biologics such as monoclonal antibodies. However, it is challenging to maintain both high viable cell densities and productivities at the same time for long culture durations. One of the key controls in a perfusion process is the perfusion rate which determines the nutrient availability and potentially controls the cell metabolism. Cell Specific Perfusion Rate (CSPR) is a feed rate proportional to the viable cell density while Biomass Specific Perfusion Rate (BSPR) is a feed rate proportional to the biomass (cell volume multiply by cell density). In this study, perfusion cultures were run at three BSPRs in the production phase. Low BSPR favored a growth arresting state that led to gradual increase in cell volume, which in turn led to an increase in net perfusion rate proportional to the increase in cell volume. Consequently, at low BSPR, while the cell viability and cell density decreased, high specific productivity of 55 pg per cell per day was achieved. In contrast, the specific productivity was lower in bioreactors operating at a high BSPR. The ability to modulate the cell metabolism by using BSPR was confirmed when the specific productivity increased after lowering the BSPR in one of the bioreactors that was initially operating at a high BSPR. This study demonstrated that BSPR significantly influenced cell growth, metabolism, and productivity in cultures with variable cell volumes.

Systematic evaluation of genome-wide metabolic landscapes in lactic acid bacteria reveals diet- and strain-specific probiotic idiosyncrasies.

Lactic acid bacteria (LAB) are well known to elicit health benefits in humans, but their functional metabolic landscapes remain unexplored. Here, we analyze differences in growth, intestinal persistence, and postbiotic biosynthesis of six representative LAB and their interactions with 15 gut bacteria under 11 dietary regimes by combining multi-omics and in silico modeling. We confirmed predictions on short-term persistence of LAB and their interactions with commensals using cecal microbiome abundance and spent-medium experiments. Our analyses indicate that probiotic attributes are both diet and species specific and cannot be solely explained using genomics. For example, although both Lacticaseibacillus casei and Lactiplantibacillus plantarum encode similarly sized genomes with diverse capabilities, L. casei exhibits a more desirable phenotype. In addition, "high-fat/low-carb" diets more likely lead to detrimental outcomes for most LAB. Collectively, our results highlight that probiotics are not "one size fits all" health supplements and lay the foundation for personalized probiotic design.