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Since its discovery in the late 1970s, emulsan has been the subject of significant interest for fundamental biosynthesis and structure–function relationships as well as for its potential industrial applications. These studies initially examined the emulsification properties of the compound, while more recent efforts have focused on potential biomedical applications. As a result of this change of focus, it became necessary to more completely characterize the structure of the emulsan molecule and to develop a more reproducible purification process. We review previous studies with emulsan and explain how prior notions were recently shown to be incorrect through the development of a new purification process. More recent genetic modification of the relevant operon is also reviewed. Finally, the potential applications for the new purified polymer will be discussed. [ABSTRACT FROM AUTHOR]

Acinetobacter venetianus RAG-1 produces an extracellular protein/high-molecular-weight (HMW) polysaccharide complex termed emulsan. As an emulsion stabilizer, emulsan has potential industrial applications. To control the molecular weight of the polymer, a stable chromosomal mutant was generated where RAG-1 wza, wzb, wzc genes were replaced by Escherichia coli homologs. The heterologous Wza, Wzb, Wzc proteins restored production of HMW polysaccharide. The polymer produced was of higher molecular weight than from the parent strain and with the cells exhibiting modified hydrophobicity. [ABSTRACT FROM AUTHOR]

A Nile red fluorescent technique to quantify 20–200 μg ml−1 of emulsan was developed. Nile red dissolved in DMSO showed an adsorption peak at 552 nm, and emission peak at 636 nm, with molar extinction coefficient of 19,600 cm−1 M−1. Nile red fluorescence in DMSO was proportionally quenched by emulsan and the quenching was time-dependent. The assay was used to follow the production of emulsan by cultures of Acinetobacter venetianus RAG-1. [ABSTRACT FROM AUTHOR]