Effects of increasing the metabolic flux pools of precursors for 2,3-BD production in K. oxytoca. (A) 3D mesh plot graph as a continuous surface for in silico flux solution space of K. oxytoca wild-type strain correlated with cell growth rate, byproducts formation rate, and 2,3-BD production rate and its corresponding contour graph. (B) Method to examine the effects of increasing the metabolic flux pools of 2,3-BD precursors. In order to increase the metabolic flux pools of 2,3-BD precursors, all reactions that consume the target precursor were eliminated except for reactions that exist in 2,3-BD biosynthetic pathway and essential reactions for growth on the basis of the wild-type strain of KoxGSC1457. Because the first priority of a actual cell is survival, the maximal point of in silico cell growth rate is generally useful to predict the actual state of a cell, which is indicated by an arrow. Byproduct contains ethanol and several organic acids: lactic acid, acetic acid, succinic acid, and formic acid. (C) Schematic metabolic pathway related with 2,3-BD production and 3D mesh plot graphs as a continuous surface for in silico flux solution spaces of cases that increase each metabolic flux pool of 2,3-BD precursors and its corresponding contour graphs. The colors changed by gradation in graph indicate the value of cell growth rate. The red color means larger value of cell growth rate than other colors.
Park et al. Microbial Cell Factories 2013 12:20 doi:10.1186/1475-2859-12-20