Gas bubble induced oil recovery from emulsions stabilised by yeast components

Heeres, Arjan S.; Heijnen, Joseph J.; Wielen, Luuk A.M. van der; Cuellar, Maria C.

doi:10.1016/j.ces.2016.02.011

Cited by 18 publications

(11 citation statements)

References 25 publications

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“…The integrated process presented in this work consists of a well‐mixed fermentation compartment operating in fed‐batch mode, connected to an external bubble column which typically operates at milder mixing conditions to promote oil recovery (Figure B). The main subprocesses taking place in the separation column are: i) circulation of the broth through the column; ii) mixing of the bulk liquid due to bubbles; iii) creaming of the oil droplets due to difference of density; and iv) coalescence of separated oil droplets into a clear oil layer on the top part of the column aided by the gas bubbles.…”

Section: Theoretical Backgroundmentioning

confidence: 99%

“…However, when designing the recovery compartment, not only hydrodynamics are important but also cellular responses and their effect on productivity and recovery. Although mild mixing conditions are required in the column to promote oil creaming this regime could lead to cellular stress caused by oxygen or nutrients limitation (Figure ). The possible consequences are diverse, such as release of SACs that include proteins, polysaccharides, carboxylic acids, to the increase of cell membrane hydrophobicity, loss of productivity and viability .…”

Section: Theoretical Backgroundmentioning

confidence: 99%

“…Model fermentations with wild‐type Escherichia coliEscherichia coli were performed, and hexadecane was eventually added to mimic microbial oil production and/or solvent extraction. Hexadecane was chosen due to its biocompatibility (log P of 8.8), its similarity in number of carbons compared to commercial microbial oils like sesquiterpenes (C 15 ), and the availability of GEOR data with this organic phase . This approach allows to fix the oil concentration regardless of fermentation performance.…”

Section: Theoretical Backgroundmentioning

confidence: 99%

“…Recently a gas‐enhanced oil recovery (GEOR) technology has been proposed as an alternative to recover emulsified fermentation products . This technology consists of promoting the coalescence of oil droplets forming a continuous oil layer by passing gas bubbles through an emulsion.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Integration of Gas Enhanced Oil Recovery in Multiphase Fermentations for the Microbial Production of Fuels and Chemicals

Cuesta

Keijzers

Wielen

et al. 2018

Biotechnology Journal

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In multiphase fermentations where the product forms a second liquid phase or where solvents are added for product extraction, turbulent conditions disperse the oil phase as droplets. Surface-active components (SACs) present in the fermentation broth can stabilize the product droplets thus forming an emulsion. Breaking this emulsion increases process complexity and consequently the production cost. In previous works, it has been proposed to promote demulsification of oil/supernatant emulsions in an off-line batch bubble column operating at low gas flow rate. The aim of this study is to test the performance of this recovery method integrated to a fermentation, allowing for continuous removal of the oil phase. A 500 mL bubble column is successfully integrated with a 2 L reactor during 24 h without affecting cell growth or cell viability. However, higher levels of surfactants and emulsion stability are measured in the integrated system compared to a base case, reducing its capacity for oil recovery. This is related to release of SACs due to cellular stress when circulating through the recovery column. Therefore, it is concluded that the gas bubble-induced oil recovery method allows for oil separation and cell recycling without compromising fermentation performance; however, tuning of the column parameters considering increased levels of SACs due to cellular stress is required for improving oil recovery.

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Section: Theoretical Backgroundmentioning

confidence: 99%

Section: Theoretical Backgroundmentioning

confidence: 99%

Section: Theoretical Backgroundmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Integration of Gas Enhanced Oil Recovery in Multiphase Fermentations for the Microbial Production of Fuels and Chemicals

Cuesta

Keijzers

Wielen

et al. 2018

Biotechnology Journal

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“…However, for economically feasible production of the biofuel, the recovery process has to be cheap, so a low cost process technology should be used. Technologies such as gas enhanced oil recovery (Heeres et al, 2016), magnetic nanoparticles (Furtado et al, 2015) and catastrophic phase inversion (Glonke et al, 2016) have been proposed as alternative de-emulsification methods. Furthermore, gravity separators such as plate droplet separators offer opportunities for either concentrating the disperse phase prior to one of the de-emulsification methods above, or for the complete separation of the disperse phase when the droplet stabilisation can be mitigated during the conversion process.…”

Section: Introductionmentioning

confidence: 99%

Photo-Optical In-Situ Measurement of Drop Size Distributions: Applications in Research and Industry

Panckow

Reinecke²,

Cuellar

et al. 2017

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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-The exact knowledge of Drop Size Distributions (DSD) plays a major role in various fields of applications to control and optimise processes as well as reduce waste. In the microbial production of advanced biofuels, oil droplets are produced under turbulent conditions in an aqueous medium containing many surface active components, which might hinder the recovery of the product. Knowledge of DSD is thus essential for process optimisation. This study demonstrates the capability of a photo-optical measurement method for DSD measurement in fermentation broth and in plate separators aimed at cost reduction in the microbial production of advanced biofuels. Measurements were made with model mixtures in a bioreactor, and at the inlet and outlet of a plate separator. In the bioreactor, the method was effective in detecting a broad range of droplet sizes and in differentiating other disperse components (e.g. microbial cells and gas bubbles). In the plate separator, the method was effective in determining the influence of the varied parameters on the separation efficiency.Résumé -Mesure photo-optique in-situ de la distribution des taille des gouttes : applications dans la recherche et l'industrie -La connaissance approfondie de la distribution du diamètre des gouttelettes joue un rôle important dans des diverses applications des contrôles et d'optimisations des processus, de plus elle permet de réduire le gaspillage. Pendant la production microbienne de biocarburants avancés, des gouttelettes d'huiles sont produites sous les effets des turbulences du milieu aqueux contenant beaucoup de substances tensio-actives, ce qui pourrait entraver la récupération du produit. La connaissance de la distribution du diamètre des gouttelettes est donc essentielle pour l'optimisation des processus. Cette étude montre les possibilités offertes par une méthode de mesure photo-optique pour les mesures de la taille des gouttelettes dans des bouillons de fermentations et dans des séparateurs à plaques, ceci vise à réduire les coûts dans la production microbienne de biocarburants avancés. Les mesures ont été effectuées avec des mélanges modèles dans un bioréacteur ainsi qu'à l'entrée et à la sortie d'une plaque de séparation. Dans le bioréacteur, le procédé est efficace dans la détection d'une large gamme de tailles de gouttelettes et dans la différenciation des autres composants dispersés (par exemple des cellules microbiennes et des bulles de gaz). Dans le séparateur à plaque, le procédé est efficace, car il détermine l'influence de différents paramètres sur l'efficacité de la séparation.Oil & Gas Science and Technology -Rev. IFP Energies nouvelles (2017) 72, 14 Ó R.P. Panckow et al., published by IFP Energies nouvelles, 2017 DOI: 10.2516 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. LIST OF SYMBOLS AND/OR NOT...

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The role of Saccharomyces cerevisiae in stabilizing emulsions of hexadecane in aqueous media

Meirelles

Cunha

Gombert

2018

Appl Microbiol Biotechnol

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During downstream operations involved in the purification of hydrophobic biofuels produced by microorganisms, undesired stable emulsions may be formed. Understanding the mechanisms behind this stability is a pre-requisite for designing cost-effective strategies to break these emulsions. In this work, we aimed at increasing our knowledge on the mechanisms responsible for stabilizing yeast-containing oil-in-water emulsions. For this purpose, emulsions containing hexadecane and different yeast-based aqueous phases were prepared and analyzed for phase separation, surface charge density, particle size, and rheology. First, we observed that compounds present in fresh tablet baker's yeast contribute to emulsion stability. In order to eliminate this effect, we generated stocks with this yeast in the laboratory, and compared its performance with an industrial fuel ethanol strain, namely Saccharomyces cerevisiae PE-2. We confirmed that the presence of yeast cells enhances emulsion stability. The cultivation medium (complex or defined) in which cells are grown, as well as the physiological state of the cells (pre- or post-diauxic), prior to emulsion preparation, influenced emulsion stability. The smaller cell size of tablet yeast probably also contributes to more stable emulsions, when compared to those prepared with yeast cells grown in the laboratory. Baker's and fuel ethanol yeast cells in post-diauxic phase promote the formation of more stable emulsions than those with cells in the pre-diauxic physiological state. Finally, we propose a mechanism to explain the enhanced emulsion stability due to the presence of yeast cells, with electrostatic repulsion between emulsion droplets having the prevailing effect.

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Gas bubble induced oil recovery from emulsions stabilised by yeast components

Cited by 18 publications

References 25 publications

Integration of Gas Enhanced Oil Recovery in Multiphase Fermentations for the Microbial Production of Fuels and Chemicals

Integration of Gas Enhanced Oil Recovery in Multiphase Fermentations for the Microbial Production of Fuels and Chemicals

Photo-Optical In-Situ Measurement of Drop Size Distributions: Applications in Research and Industry

The role of Saccharomyces cerevisiae in stabilizing emulsions of hexadecane in aqueous media

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