Improved performance of Pseudomonas putida in a bioelectrochemical system through overexpression of periplasmic glucose dehydrogenase. Issue 1 (6th October 2017) - Yu, Shiqin
Abstract: It was recently demonstrated that a bioelectrochemical system (BES) with a redox mediator allowed Pseudomonas putida to perform anoxic metabolism, converting sugar to sugar acids with high yield. However, the low productivity currently limits the application of this technology. To improve productivity, the strain was optimized through improved expression of glucose dehydrogenase (GCD) and gluconate dehydrogenase (GAD). In addition, quantitative real‐time RT‐PCR analysis revealed the intrinsic self‐regulation of GCD and GAD. Utilizing this self‐regulation system, the single overexpression strain (GCD) gave an outstanding performance in the electron transfer rate and 2‐ketogluconic acid (2KGA) productivity. The peak anodic current density, specific glucose uptake rate and 2KGA producing rate were 0.12 mA/cm 2, 0.27 ± 0.02 mmol/gCDW /hr and 0.25 ± 0.02 mmol/gCDW /hr, which were 327%, 477%, and 644% of the values of wild‐type P. putida KT2440, respectively. This work demonstrates that expression of periplasmic dehydrogenases involved in electron transfer can significantly improve productivity in the BES. Abstract : Anodic respiration using mediated electron transfer enables anaerobic glucose oxidation in Pseudomonas putida using a bioelectrochemical system. Overexpression of periplasmatic dehydrogenases enabled a tremendous increase in electron transfer and thus reduced process time. This work highlights the potential of combining metabolic engineering on the one hand with microbial electrochemical technologies on the other hand for development and control of new redox driven bioprocesses.