Carboxylic acid consumption and production by Corynebacterium glutamicum_LC-MS/MS

Corynebacterium glutamicum is well-known as an industrial workhorse, most notably for its use in the bulk production of amino acids in the feed and food sector. Fast growth and robustness against oscillatory oxygen availability, which can occur in large-scale bioreactors, are advantageous properties of this bacterium. However, previous studies of the effect of gradients in scale-down reactors with complex media disclosed an accumulation of several carboxylic acids and a parallel decrease of growth and product accumulation by C. glutamicum. This study addresses the impact of carboxylic acids, e.g. acetate and L-lactate, on the cultivation process and their potential role in scale up related performance losses. In order to mimic a discontinuous oxygen supply, a fluctuating power input in shake flask and stirred tank cultivations with mineral salt was applied. One focus of this study is to identify relative changes in the proteome due to the differing availability of carboxylic acids under discontinuous oxygen supply.