TY - JOUR
T1 - Integration of Gas Enhanced Oil Recovery in Multiphase Fermentations for the Microbial Production of Fuels and Chemicals
AU - Pedraza-de la Cuesta, Susana
AU - Keijzers, Lore
AU - van der Wielen, Luuk A.M.
AU - Cuellar, Maria C.
N1 - Publisher Copyright:
© 2018 The Authors. Biotechnology Journal Published by Wiley-VCHVerlag GmbH & Co. KGaA, Weinheim
PY - 2018/4
Y1 - 2018/4
N2 - 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.
AB - 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.
KW - emulsion
KW - fermentation
KW - integration
KW - microbial biofuels
KW - product recovery
UR - http://www.scopus.com/inward/record.url?scp=85041238468&partnerID=8YFLogxK
U2 - 10.1002/biot.201700478
DO - 10.1002/biot.201700478
M3 - Article
C2 - 29345420
AN - SCOPUS:85041238468
SN - 1860-6768
VL - 13
SP - e1700478
JO - Biotechnology Journal
JF - Biotechnology Journal
IS - 4
M1 - 1700478
ER -