Rhamnolipid production by <i>Burkholderia plantarii</i> DSM 9509^T

Abstract

Abstract The Burkholderia plantarii type strain DSM 9509 T was shown to produce extracellular rhamnolipids that clearly differ in structure and properties from the Pseudomonas aeruginosa rhamnolipids. The type strain has not been previously described as rhamnolipid producer. B. plantarii DSM 9509 T was cultivated in a parallel bioreactor system and produced up to 45.74 mg/L of rhamnolipids when grown in glucose supplemented rich medium. The structure of the main rhamnolipid Rha 2 ‐C 14 ‐C 14 ( L ‐rhamnopyranosyl‐ L ‐rhamnopyranosyl‐β‐hydroxytetradecanoyl‐β‐hydroxytetradecanoate) was verified by MS/MS. The purified rhamnolipid Rha 2 ‐C 14 ‐C 14 lowered the equilibrium surface tension of distilled water to 29.4 mN/m. The CMC was between 15 and 20 mg/L. In this study, growth and product formation were investigated under biotechnological aspects. Practical applications : B. plantarii DSM 9509 T produces a rhamnolipid that differs in structure from P. aeruginosa rhamnolipids and exhibits excellent surfactant properties. An essential advantage in comparison to P. aeruginosa is that B. plantarii DSM 9509 T is a Biosafety Level 1 microorganism and not pathogenic in humans. A biotechnological production of the Burkholderia rhamnolipids could lead to their application in detergents, pharmaceuticals, and other industries providing new products on the biosurfactant market.