Growth Model for Continuous Culture of a Hydrogen-Oxidizing Bacterium, Hydrogenophilus thermoluteolus Strain TH-1

Hydrogenophilus thermoluteolus strain TH-1 is a thermophilic hydrogen-oxidizing bacterium that can autotrophically grow using H₂, CO_2, and O₂ with the highest rate among autotrophs. However, despite its significant potential for use in biomanufacturing from CO₂, no model to date has accurately described strain TH-1 growth under both H₂- and O₂-limiting conditions. Here, we report on a growth model for continuous culture. Theoretical equations were established for cell yields from the substrate consumption, overall mass transfer coefficients of H₂ and O₂, cell densities, and dilution rates. These equations were globally fitted to a series of cell culture profiles. Global fitting showed that the model closely reproduced cell production in continuous culture under H₂-limiting and O₂-limiting conditions. This model will be useful for understanding culture profiles and optimizing production.