Hydrodynamics for the integration of fermentation and separation in the production of diesel and jet biofuels

Over the years, various technologies have been developed to produce and separate advanced biomolecules. These technologies range from complex terpenoids for pharmaceuticals and flavors to commodity chemicals and fuels via the fermentative route. These compounds are often poorly water soluble, phase splitting organic compounds or inhibitory and unstable necessitating addition of an extractive, second liquid phase for product removal. The turbulent conditions in the multiphasic fermentation coupled with the presence of surface-active compounds in the medium create a stable emulsion that is difficult to separate in conventional systems. Technologies such as centrifugation and de-emulsifiers have been used to separate the emulsion and recover the product. However, these type of recovery processes are expensive, drastically increase the final product’s environmental footprint and often hamper cell recycling.BT/Bioprocess Engineerin

Impact of flocculant addition in oil recovery from multiphasic fermentations

Emulsion formation is a major concern when dealing with multiphasic fermentations. Flocculants can be used together with other demulsification techniques to improve oil recovery in multiphasic fermentations. In this paper, the impact of adding flocculants during a multiphasic fermentation with 10 wt% dodecane, to destabilize the broth emulsion, improve creaming formation and enhance oil recovery is studied. Flocculants, CaCl2 and (NH4)2SO4 were shown to be the most promising flocculants. Flocculant addition, their time of addition, and its impact on multiphasic fermentations has been evaluated by comparing fermentation performance against reference fermentations and three oil recovery methods: gravity settling, gas enhanced oil recovery and centrifugation. When adding 75 mM of (NH4)2SO4 during fermentation, the creaming rate during gravity settling increased 3-fold and the oil recovery by gas enhanced oil recovery was 35%, without altering fermentation performance. Addition of CaCl2 during fermentation resulted in 88% and 67% oil recovery for early and late addition, which is a 4 and 3-fold increase in comparison with the reference. Yet, CaCl2 deviated from standard fermentation performance when added immediately after second phase addition. In conclusion, flocculant addition during multiphasic fermentation can be used to destabilize microbial emulsions and potentially improve in situ oil recovery.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.BT/Bioprocess EngineeringExecutive boardChemE/Transport Phenomen