Enzymatic modification of microbial rhamnolipids

IVANA MAGARIO; FRANK LEITERMANN; ANKE NEUMANN; OLIVER VIELHAUER; CHRISTOPH SYLDATK

Edinburgo

Congreso; 3rd Euro Fed Lipid Congress.; 2004

Universidad de Edinburgo

Rhamnolipids are surface-active agents being used e.g. as surface cleaning agents. They are produced by Pseudomonas sp. and, though there are different kinds of them, the most relevant have a bond of one or two units of L-(+)-rhamnopyranoside with a (R,R)-3-(3-hydroxydecanoyloxy)decanoic acid. Enzymatic modifications of the mixture resulting from the production by Pseudomonas sp. are necessary in order to obtain a unique species with higher tensoactive properties. The first attempt consists of the use of rhamnosidases to hydrolyze one unit of L-(+)-rhamnose in a rhamnolipid molecule containing two of them. A further cleavage could be performed to achieve a higher quantity of L-(+)-rhamnose, which is starting material for the synthesis of flavor agents, and (R,R)-3-(3-hydroxydecanoyloxy)decanoic acid, an interesting source of the optic-active ß-hydroxydecanoic acid, used as starting material for chemical synthesis (1). Therefore, screening of rhamnosidases, optimization of the biotransformation of rhamnolipids and characterization of the kinetics for both reactions should be accomplished. Since most of the rhamnosidases have an acidic pH-optimum, and due to the low solubility of rhamnolipids under these conditions, bioconversion in organic solvents and biphasic systems should be considered. Consequently, a potential separation of the products in situ could be obtained, since L-(+)-rhamnose would remain in water and the (R,R)-3-(3 hydroxydecanoyloxy)decanoic acid in the organic phase. For a competitive industrial application, the recovery of the enzyme is essential. Therefore, immobilization methods of the rhamnosidase should be tested.