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Stirred tank bioreactors are the most widely used method for the large-scale culture of mammalian cells. However, the scale of stirred tank bioreactors is limited by insufficient oxygen/nutrient mixing and the accumulation of waste products in high cell density cultures. The most effective method to solve these problems is to increase the stirring rate; this usually leads to increased cell proliferation, but can decrease the utilization of nutrients for recombinant protein synthesis. To investigate the effects of stirring rate on the proliferation, metabolism, and recombinant protein yield of microencapsulated recombinant Chinese hamster ovary (rCHO) cells, the cells were cultured under different stirring rates, and cell viability, metabolic activity, and protein yield were measured. Microencapsulation promoted Desmodus rotundus salivary plasminogen activator expression, and higher stirring rates promoted increases in microencapsulated cell density and metabolic activity. However, the maximum yield of recombinant protein was obtained at a moderate stirring rate, whereas protein yield was decreased at the highest tested stirring rate. The stirring rate had a significant impact on the growth and protein expression of microencapsulated rCHO cells, and a specific stirring rate was identified to maximize the yield of recombinant protein. [ABSTRACT FROM AUTHOR]

Abstract In the present work, five polysaccharides were selected as co-encapsulant of skim milk based matrix and used for the microencapsulation of Lactobacillus paracasei Lpc-37 by spray drying. The morphological characterization, physical properties, encapsulation efficiency, gastrointestinal simulation, and storage stability of microencapsules were examined to evaluate the protective capacity against the adverse conditions of the different wall matrices. Addition of polysaccharides was associated with the enhancement of physical performance of microencapsulated powders, such as the flowability and water activity. Encapsulation matrices containing gum Arabic showed the greatest encapsulation efficiency of 97.1% (maximum survival 7.78 log CFU/g). L. paracasei Lpc-37 encapsulated with the matrices incorporating sodium alginate or sodium carboxymethylcellulose exhibited higher survival (>6.5 log CFU/g) after exposed to simulated gastrointestinal condition and lower viability loss (<0.3 log CFU/g) after 8 weeks of refrigerated storage. The application of polysaccharides, however, showed the tendency of higher hygroscopicity and lower stability of the powders in high temperature and humid environment. Highlights • The applied polysaccharides improved the flowability of microencapsulated powder. • Gum Arabic maintained L. paracasei viable during spray-drying process. • Sodium alginate and sodium carboxymethylcellulose enhanced L. paracasei viability during simulated digestion. [ABSTRACT FROM AUTHOR]