Abstract: A method for selectively enriching for a microorganism able to metabolise a test substrate, and/or the enrichment of an enzyme involved in the metabolism of the test substrate, the method comprising the steps of: a) providing a population of microorganisms in a vessel, b) feeding fluid into the vessel at a controlled flow rate commencing with an initial flow rate, the fluid comprising a nutrient medium and, for at least part of the feed period, the test substrate, c) producing a signal indicative of the level of a metabolism indicator over the time-frame of the enrichment, and d) providing an output based on the signal to enable assessment of selective enrichment of a microorganism that metabolises the test substrate, and/or the enrichment of an enzyme produced by the microorganism that is involved in the metabolism of the test substrate. To accelerate the enrichment process, conditions may be set to increase the flow rate in stages as a steady state is detected.

Abstract: A cell culture medium which is low in dissolved carbon dioxide is disclosed. The medium contains less than about 1 g/L added sodium bicarbonate and includes an organic buffer and a metal complexing agent. The medium is preferably essentially free of added sodium bicarbonate. Methods of use of the medium in culturing mammalian cells, particularly cells engineered to produce recombinant factor VIII, are also disclosed.

Abstract: A chemiluminescence-based gel assay may be used as an indicator of fermenter health. The assay is performed using a sample of fermentation medium essentially directly from the fermenter (with no need for complicated purification of the sample before performing the assay). Results from the assay may be correlated with the final product purification yield of a given protein/purification protocol system. This may then be used as a predictor of purification yield before actually performing the purification.