title: Effect of emulsified feeding of oily substrate via submerged ceramic membranes on surfactant production in Pseudomonas aeruginosa fermentation.
abstract: Aqueous two-phase systems often face mass transfer limitations due to very poor miscibility of the fluids, and to enhance the homogeneity (or emulsification) in the reaction volume, high energy inputs are required which result in high shear forces in the culture medium. For the purposes of emulsification, microporous systems have advantages over other conventional methods due to mild operating conditions and narrow droplet-size distribution. In this study, emulsification within the culture volume was achieved by feeding the oily substrate (dispersed phase) into the aqueous medium (dispersion phase) via ceramic membranes integrated in the bioreactor. The method was investigated for bioprocesses aimed at producing rhamnolipids and polyhydroxyalkanoates (PHA). Better homogenization of the mixed volume and hence improved consumption of oily substrate was successful. Surfactants are produced by various bacterial cultures, especially Pseudomonas aeruginosa species, when oil is present as the only carbon source. Are surfactants produced only as a result of bacteria feeding on the oily substrate, or as a requirement to feed on the oily substrate, owing to their surface-active characteristics? This paper also intends to draw some conclusions in this respect.
authors.affiliation: upt GmbH, Im Statdwald Geb. D3.3, Saarbruecken, Germany. dhariwal@upt.uni-saarland.de
authors.forename: Anuj
authors.initials: A
authors.lastname: Dhariwal
authors.forename: Markus
authors.initials: M
authors.lastname: Mohrdieck
authors.forename: Frank
authors.initials: F
authors.lastname: Leitermann
authors.forename: Ignacio Martin
authors.initials: IM
authors.lastname: Arjol
authors.forename: Angels
authors.initials: A
authors.lastname: Manresa
authors.forename: Christoph
authors.initials: C
authors.lastname: Syldatk
authors.forename: Hans Dieter
authors.initials: HD
authors.lastname: Janke
authors.forename: Horst
authors.initials: H
authors.lastname: Chmiel
mesh_terms: D002516:Ceramics / Q000737:chemistry*; D004655:Emulsions / Q000737:chemistry; D005285:Fermentation; D008567:Membranes, Artificial; D009821:Oils / Q000737:chemistry; D044367:Phase Transition; D011550:Pseudomonas aeruginosa / Q000378:metabolism*; D013501:Surface-Active Agents / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D004655:Emulsions; D008567:Membranes, Artificial; D009821:Oils; D013501:Surface-Active Agents