Oxygen transfer in multiphase bioprocesses

A systematic quantification and correlation of oxygen transfer coefficients and interfacial area in simulated model hydrocarbon‐based bioprocesses in stirred tank reactors

Background.

Hydrocarbons are attractive substrates for bioconversion to an expansive range of commodity products. Since these are aerobic bioprocesses, an overall volumetric oxygen transfer coefficient (K_La) which facilitates sufficient oxygen transfer is critical to their optimum operation, design and scale‐up.

Results.

The significant parameters influencing K_La, the oxygen transfer area and the oxygen transfer coefficient (K_L) were identified in simulated model hydrocarbon‐based bioprocesses comprising alkane–aqueous dispersions with suspended yeast using a rigorous statistical approach. K_La was measured using the dynamic procedure incorporating the probe constant. Transfer area was determined using photography and image analysis. Concurrent determination and correlation of K_La, K_L and transfer area, under regimes defined by agitation rate and yeast and alkane concentration, facilitated quantification of the dominant causative factor underpinning K_La behaviour as the Sauter mean diameter or K_L, depending on the operational regime. Potential mechanisms which corroborate these results have been discussed.

Conclusion.

The systematic identification, quantification and correlation of the parameters and mechanisms impacting on K_La in hydrocarbon‐based bioprocesses, and the comprehensive and statistically validated empirical data, provide an expedient platform to support future development of a fundamental model for the prediction of K_La in these systems.

The full article is available here: https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.4897