Bioprocess scale-down simulators are used to investi- gate the phenomena occurring in industrial scale cul- tivations. The aim is to simulate the large-scale con- ditions, characterized by long mixing times intro- ducing local gradients into the bioreactor, in labora- tory scale bioreactor. We have expanded the current physiological knowledge about the consequences of such cultivation conditions from well-known mixed- acid fermentation to amino acid metabolism. Several interesting deviations were observed for amino acids derived from pyruvate when a STR-PFR scale-down simulator and a regular STR fed-batch cultivation were compared. In this article we show that the cul- tivation of Escherichia coli K-12 substrain W3110 in a scale-down two-compartment bioreactor has conse- quences on the free amino acid pools. Repeated occu- rrence of high glucose zones affects the biosynthesis of amino acids derived from pyruvate. This is inte- resting since the pyruvate based amino acids are pre- cursors of the branched chain amino acid pathway, which is further disturbed by an unbalanced regulation caused by a frameshift mutation in the ilvG gene of E. coli K-12 strains. As a consequence the for- mation of non-typical amino acid norvaline was de- tected in the two compartment bioreactor cultivation.
Sprange K Brazier J, Cook SP, Craig C, Hind D, Walters SJ, Windle G, Woods R, Keetharuth AD, Chater T, Horner K, M. G. A., Sprange, K., Mountain, G. A., Brazier, J., Cook, S. P., Craig, C., … Horner, K. (2013). Lifestyle Matters for maintenance of health and wellbeing in people aged 65 years and over: study protocol for a randomised controlled trial. Trials, 14(1), 302. https://doi.org/10.4236/abb.2011.25049