Towards Sustainable Bioinoculants: A Fermentation Strategy for High Cell Density Cultivation of Paraburkholderia sp. SOS3, a Plant Growth-Promoting Bacterium Isolated in Queensland, Australia

Paraburkholderia sp. SOS3 is a plant growth-promoting bacterium (PGPB) that displays pleiotropic effects and has the potential to be applied at large scale across several agronomically important crops. The use of suitable option reduce chemical fertilisers. While benefits have been demonstrated in vitro, its applications are limited due low biomass yield current batch culture systems. Here, we developed strategy for high-cell density cultivation instrumented bioreactors, moving from low-biomass complex medium high-biomass semi-defined medium. We achieved 40-fold increase production, achieving cell densities up 11 g/L (OD600 = 40). This result was when cultivated using fed-batch strategy. Biomass productivity, initially 0.02 g/L/h cultures, improved 12-fold, reaching 0.24 during cultures. also 10-fold 0.07 0.71 gbiomass/gsolids. Analysis fermentation profile indicated minimal production by-products accumulation polyhydroxybutyrate (PHB) exponential growth phase associated with nitrogen limitation By implementing proteomics analysis identified expression four metabolic pathways effects, which may used as qualitative parameter guarantee efficacy bioinoculant. Ultimately, confirmed cultures maintained their capacity tested sorghum maize under glasshouse conditions.