Bioprocess

About: Bioprocess is a research topic. Over the lifetime, 2219 publications have been published within this topic receiving 50972 citations.

Verification of a new biocompatible single-use film formulation with optimized additive content for multiple bioprocess applications

Abstract: Single-use bioprocessing bags and bioreactors gained significant importance in the industry as they offer a number of advantages over traditional stainless steel solutions. However, there is continued concern that the plastic materials might release potentially toxic substances negatively impacting cell growth and product titers, or even compromise drug safety when using single-use bags for intermediate or drug substance storage. In this study, we have focused on the in vitro detection of potentially cytotoxic leachables originating from the recently developed new polyethylene (PE) multilayer film called S80. This new film was developed to guarantee biocompatibility for multiple bioprocess applications, for example, storage of process fluids, mixing, and cell culture bioreactors. For this purpose, we examined a protein-free cell culture medium that had been used to extract leachables from freshly gamma-irradiated sample bags in a standardized cell culture assay. We investigated sample bags from films generated to establish the operating ranges of the film extrusion process. Further, we studied sample bags of different age after gamma-irradiation and finally, we performed extended media extraction trials at cold room conditions using sample bags. In contrast to a nonoptimized film formulation, our data demonstrate no cytotoxic effect of the S80 polymer film formulation under any of the investigated conditions. The S80 film formulation is based on an optimized PE polymer composition and additive package. Full traceability alongside specifications and controls of all critical raw materials, and process controls of the manufacturing process, that is, film extrusion and gamma-irradiation, have been established to ensure lot-to-lot consistency. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:1171–1176, 2014

Fed-batch microbioreactor platform for scale down and analysis of a plasmid DNA production process.

Abstract: The rising costs of bioprocess research and development emphasize the need for high-throughput, low-cost alternatives to bench-scale bioreactors for process development. In particular, there is a need for platforms that can go beyond simple batch growth of the organism of interest to include more advanced monitoring, control, and operation schemes such as fed-batch or continuous. We have developed a 1-mL microbioreactor capable of monitoring and control of dissolved oxygen, pH, and temperature. Optical density can also be measured online for continuous monitoring of cell growth. To test our microbioreactor platform, we used production of a plasmid DNA vaccine vector (pVAX1-GFP) in Escherichia coli via a fed-batch temperature-inducible process as a model system. We demonstrated that our platform can accurately predict growth, glycerol and acetate concentrations, as well as plasmid copy number and quality obtained in a bench-scale bioreactor. The predictive abilities of the micro-scale system were robust over a range of feed rates as long as key process parameters, such as dissolved oxygen, were kept constant across scales. We have highlighted plasmid DNA production as a potential application for our microbioreactor, but the device has broad utility for microbial process development in other industries as well.

Oxygen Uptake Rate Soft-Sensing via Dynamic kLa Computation: Cell Volume and Metabolic Transition Prediction in Mammalian Bioprocesses.

Abstract: In aerobic cell cultivation processes, dissolved oxygen is a key process parameter, and an optimal oxygen supply has to be ensured for proper process performance. To achieve optimal growth and/or product formation, the rate of oxygen transfer has to be in right balance with the consumption by cells. In this study, a 15 L mammalian cell culture bioreactor was characterized with respect to kLa under varying process conditions. The resulting dynamic kLa description combined with functions for the calculation of oxygen concentrations under prevailing process conditions led to an easy-to-apply model, that allows real-time calculation of the oxygen uptake rate (OUR) throughout the bioprocess without off-gas analyzers. Subsequently, the established OUR soft-sensor was applied in a series of 13 CHO fed-batch cultivations. The OUR was found to be directly associated with the amount of viable biomass in the system, and deploying of cell volumes instead of cell counts led to higher correlations. A two-segment linear model predicted the viable biomass in the system sufficiently. The segmented model was necessary due to a metabolic transition in which the specific consumption of oxygen changed. The aspartate to glutamate ratio was identified as an indicator of this metabolic shift. The detection of such transitions is enabled by a combination of the presented dynamic OUR method with another state-of-the-art viable biomass soft-sensor. In conclusion, this hyphenated technique is a robust and powerful tool for advanced bioprocess monitoring and control based exclusively on bioreactor characteristics.