Recent research led by Anna Weimer from the Institute of Systems Biotechnology at Saarland University has shed light on the unique capabilities of Pseudomonas putida KT2440, a bacterium with significant potential for industrial bioproduction. This study, published in the journal Microbial Cell Factories, explores how this microbe can thrive in an anoxic bio-electrochemical system (BES), where it can convert glucose into valuable chemicals like 2-ketogluconate (2KG) without relying on oxygen.
Pseudomonas putida is known for its strictly aerobic nature, which typically limits its applications in bioproduction. However, the research highlights a remarkable adaptability when cultured in a BES environment, where the anode acts as the terminal electron acceptor. This innovative approach allows the bacteria to maintain metabolic activity and produce 2KG, a compound with various commercial applications, including its use in food, pharmaceuticals, and chemical industries.
The study revealed that when incubated on glucose, P. putida KT2440 does not grow but instead produces significant amounts of 2KG, alongside smaller quantities of other metabolites such as gluconate and acetate. The research team utilized 13C tracer studies to trace the origins of these products, finding that they partially derive from the carbon in the bacteria’s biomass. Over time, the cells adapted by shutting down processes like translation and cell motility to conserve energy, demonstrating a fascinating survival strategy that enables sustained metabolic activity over weeks.
One of the key findings of the study was the role of acetate in energy supply. The researchers discovered that mutants of P. putida, which were deficient in acetate production, showed improved performance in 2KG production. Notably, the double deletion mutant ∆aldBI ∆aldBII outperformed the wild type, accumulating 2KG at twice the rate and achieving a yield of 0.96 mol/mol.
Weimer emphasized the significance of their findings, stating, “By integrating transcriptomic, proteomic, and metabolomic analyses, this work provides the first systems biology insight into the electrogenic phenotype of P. putida KT2440.” This research not only enhances our understanding of the bacterium’s metabolic pathways but also opens new avenues for metabolic engineering strategies aimed at improving 2KG production.
The implications of this research are substantial for various sectors, particularly in the production of biochemicals and biofuels. The ability to produce 2KG efficiently and sustainably could lead to reduced reliance on traditional chemical processes, aligning with the growing demand for greener production methods. As industries seek to transition to more sustainable practices, the insights gained from this study could pave the way for the development of innovative bioprocesses that leverage the unique properties of Pseudomonas putida.
In summary, this research not only enhances our understanding of Pseudomonas putida’s capabilities but also presents significant commercial opportunities for industries looking to adopt more sustainable practices. The findings published in Microbial Cell Factories could very well influence future bioproduction strategies, making this an exciting area to watch in the coming years.
