Specific activity of Caa. Growth of complementation strain in TSB and minimal media with fructose. A) Specific activity of purified Strep2-tagged CA enzymes. Substrates used for this assay were bicarbonate (50 mM, dark bars) and CO2 (saturated solution, grey bars). CA activity was measured by comparing the rapid change of pH in the presence of CA to the slower pH change in the absence of CA. The pH change was monitored using phenol red and the absorbance A557nm was measured for 60 sec. Average values from three experiments were plotted with error bars representing the standard deviation. B) Cultures of R. eutropha wild type (H16 - ●), Re2428 (○), Re2428/pCaa (▼), and Re2428pCaaB (∆) in TSB media. C) Growth in minimal media with 2% fructose (w vol-1). Values represent average from three replicates with standard deviation as error bars.