Properties of hydrocarbon‐in‐water emulsions stabilized by Acinetobacter RAG‐1 emulsan

Zinaida Zosim*, David Gutnick, Eugene Rosenberg

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Emulsan is a polymeric extracellular emulsifying agent produced by Acinetobacter RAG‐1. Hydrocarbon‐in‐water emulsions (Vf of hydrocarbon of 0.01–0.10) were stabilized by small quantities of emulsan (0.02–0.2 mg/mL). Although both aliphatic and aromatic hydrocarbon emulsions were stabilized by emulsan, mixtures containing both aliphatics and aromatics were better substrates for emulsan than the individual hydrocarbon by themselves. The emulsan remained tightly bound to the hydrocarbon even after centrifugation as determined by (a) residual emulsan in the aqueous phase and (b) the fact that the resulting “cream” readily dispersed in water to reform stable emulsions. With hexadecane‐to‐emulsan weight ratio of 39 and 155, the noncoalescing oil droplets had average droplet diameters of 2.0 and 4.0 μm, respectively. Dialysis studies showed that the water‐soluble dye Rhodamine B adsorbed tightly to the interface of hexadecane–emulsan droplets although the dye did not bind to either hexadecane or emulsan alone. At saturating concentrations of dye, 2.2 μmol of dye were bound per mg emulsan.

Original languageEnglish
Pages (from-to)281-292
Number of pages12
JournalBiotechnology and Bioengineering
Issue number2
StatePublished - Feb 1982


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