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

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 (pO₂) 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 pO₂ (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 pO₂. 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.