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Increasing cell‐specific productivities (CSPs) for the production of heterologous proteins in Chinese hamster ovary (CHO) cells is an omnipresent need in the biopharmaceutical industry. The novel additive 5′‐deoxy‐5′‐(methylthio)adenosine (MTA), a chemical degradation product of S‐(5′‐adenosyl)‐ʟ‐methionine (SAM) and intermediate of polyamine biosynthesis, boosts the CSP of IgG1‐producing CHO cells by 50%. Compartment‐specific 13C flux analysis revealed a fundamental reprogramming of the central metabolism after MTA addition accompanied by cell‐cycle arrest and increased cell volumes. Carbon fluxes into the pentose‐phosphate pathway increased 22 fold in MTA‐treated cells compared to that in non‐MTA‐treated reference cells. Most likely, cytosolic ATP inhibition of phosphofructokinase mediated the carbon detour. Mitochondrial shuttle activity of the α‐ketoglurarate/malate antiporter (OGC) reversed, reducing cytosolic malate transport. In summary, NADPH supply in MTA‐treated cells improved three fold compared to that in non‐MTA‐treated cells, which can be regarded as a major factor for explaining the boosted CSPs. [ABSTRACT FROM AUTHOR]

Production of nanomagnetic particles via microbial processes offers the advantage of better biocompatibility for medical applications. However, this process is not widely applied due to the difficulties in cultivating magnetotactic bacteria in the lab. This research explored the possibilities of cultivating magnetotactic bacteria in order to produce nanomagnetic particles in the lab and in particular to find the carbon and iron sources to get the optimum yield of nanomagnetic particles. Experiments were performed as semiaerobic-batch-magnetotactic-bacteria cultivations. The carbon source in the media was varied as: sodium lactate, sodium acetate, and sodium pyruvate. As for the iron source, either Fe-citrate or Fe-quinate was used. Bacterial cell growth was monitored using the turbidometry-gravimetry method, substrate concentration was measured using high performance liquid chromatography (HPLC), while the cellular iron content was measured using electron dispersive X-ray spectroscopy (EDS) and transmission electronic microscopy (TEM). It was observed that cell growth did not correlate with the production of nanomagnetic particles. The bacteria grew best on sodium pyruvate and Fe-quinate, however, the best yield of nanomagnetic particles was obtained from the cultivation with sodium acetate and Fe-quinate. The obtained TEM images confirmed the presence of nanomagnetic particles. [ABSTRACT FROM AUTHOR]