Foam adsorption as an ex situ capture step for surfactants produced by fermentation

• Published in: Journal of biotechnology Vol. 258; pp. 181 - 189
• Main Authors: Anic, Iva, Nath, Arijit, Franco, Pedro, Wichmann, Rolf
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 20.09.2017
• Subjects: Adsorption; Bioreactors - microbiology; Biosurfactant; Chromatography, High Pressure Liquid; Ex situ separation; Fermentation; Fermentation - physiology; Foam adsorption; Glycolipids - chemistry; Glycolipids - isolation & purification; Glycolipids - metabolism; Hydrophobic and Hydrophilic Interactions; Pseudomonas putida; Pseudomonas putida - metabolism; Rhamnolipid; Surface-Active Agents - chemistry; Surface-Active Agents - isolation & purification; Surface-Active Agents - metabolism; Biosurfactant; Foam adsorption; EDX; HHI; RL; SEM; Rhamnolipid; ACN; Fermentation; Ex situ separation; Pseudomonas putida
• ISSN: 0168-1656; 1873-4863
• DOI: 10.1016/j.jbiotec.2017.07.015

•Adsorbent characteristics for efficient rhamnolipid adsorption are described.•Rhamnolipid adsorption from a foam phase has been demonstrated.•Fermentation with simultaneous separation of rhamnolipid was conducted by foam adsorption. In this report, a method for a simultaneous production and separation of a microbially synthesized rhamnolipid biosurfactant is presented. During the aerobic cultivation of flagella-free Pseudomonas putida EM383 in a 3.1L stirred tank reactor on glucose as a sole carbon source, rhamnolipids are produced and excreted into the fermentation liquid. Here, a strategy for biosurfactant capture from rhamnolipid enriched fermentation foam using hydrophobic–hydrophobic interaction was investigated. Five adsorbents were tested independently for the application of this capture technique and the best performing adsorbent was tested in a fermentation process. Cell-containing foam was allowed to flow out of the fermentor through the off-gas line and an adsorption packed bed. Foam was observed to collapse instantly, while the resultant liquid flow-through, which was largely devoid of the target biosurfactant, eluted towards the outlet channel of the packed bed column and was subsequently pumped back into the fermentor. After 48h of simultaneous fermentation and ex situ adsorption of rhamnolipids from the foam, 90% out of 5.5g of total rhamnolipids produced were found in ethanol eluate of the adsorbent material, indicating the suitability of this material for ex situ rhamnolipid capture from fermentation processes.