Genome‐Reduced Pseudomonas putida Outcompetes the Wild‐Type Strain Upon Oxygen Depletion

ABSTRACT The broad adoption of the obligate aerobe Pseudomonas putida in industrial‐scale production requires a good understanding of the effect of changing oxygen availability due to the dissolved oxygen (DO) gradients apparent at such a scale. To that end, both wild‐type P. putida KT2440 and a genome‐reduced derivative (strain SEM10) were subjected to different oxygen partial pressures (pO 2 ) in the aeration gas to evaluate the effect of low oxygen availability on growth characteristics in batch mode. Strain SEM10 consistently achieved a 12.7% higher biomass yield on glucose than the wild‐type strain during non‐DO limited growth, suggesting that genome reduction had no adverse effects on the overall growth properties. Furthermore, when exposed to oxygen depletion in cultivations at low pO 2 (0.0525 atm), strain SEM10 kept a similar biomass yield and maximum specific growth rate. In fact, the genome‐reduced strain significantly outcompeted the wild‐type strain under these conditions. SEM10 achieved 23.3% and 35.5% higher biomass yields on glucose and oxygen, respectively, compared to strain KT2440 at low pO 2 . These findings indicate that the genome‐reduced strain, SEM10, could endure oxygen depletion during growth and even outcompete the wild‐type strain under these conditions, highlighting the advantages of using streamlined strains as a platform for industrial bioprocesses. Summary An energy‐efficient, genome‐reduced strain of the Pseudomonas putida KT2440 has the potential to increase yields and rates in biochemical production. A lower energy consumption for futile processes, such as flagellar, allows allocation of this energy for product synthesis or survival. The latter being of importance when the strain is applied for the production of harsh biochemicals or intermediates. These attributes are of no use unless the obligate aerobe P. putida can tolerate scarce oxygen supplies that may occur in large‐scale cultivations. Our findings suggest that the genome‐reduced strain performs equally well under oxygen‐limited and non‐limited conditions and even outcompetes the wildtype under oxygen‐limited conditions. This highlights, for the first time, the potential application of the genome‐reduced P. putida strain for processes where oxygen limitation may occur.