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The addition of ethanol as defoamer in fermentation of rhamnolipids
Author(s) -
Sha Ruyi,
Meng Qin,
Jiang Lifang
Publication year - 2012
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.2728
Subject(s) - defoamer , fermentation , ethanol , chemistry , bioreactor , laboratory flask , rhamnolipid , polyhydroxyalkanoates , pulp and paper industry , chromatography , food science , organic chemistry , bacteria , pseudomonas aeruginosa , biology , dispersant , physics , genetics , optics , engineering , dispersion (optics)
BACKGROUND: Rhamnolipids biosurfactants mainly produced by Pseudomonas aeruginosa have a wide range of potential applications. However, production of rhamnolipids on a large scale is constrained by severe foaming in fermentation. This study addressed the applicability of organic solvents as both defoamer and carbon substrate in rhamnolipids fermentation. RESULTS: In this work, although isopropanol and n‐butanol performed better defoaming activities against rhamnolipid‐induced foams, ethanol was focused on as a potential defoamer due to its high bioavailability and low toxicity in a shaking culture of P. aeruginosa ZJU. The most appropriate dose of ethanol addition was determined to be 1% (v/v) and the best time for addition was after 48 h of culture in shaking flasks. The capability of ethanol to control foaming was further illustrated during rhamnolipids fermentation in 2 L and 50 L bioreactors. In both fermentations, the addition of ethanol not only suppressed severe foaming but also supported cell growth. CONCLUSIONS: The use of ethanol as a defoamer is a potential strategy to avoid undesirable foam in fermentation of biosurfactant. Copyright © 2012 Society of Chemical Industry