Rhamnolipids and PHAs: Recent reports on Pseudomonas-derived molecules of increasing industrial interest

Rhamnolipids (RL) and polyhydroxyalkanoates (PHA) from Pseudomonas species show a wide range of potential industrial applications. Rhamnolipids are surface-active molecules that are usually produced by Pseudomonas aeruginosa strains. Their unique properties, including detergency, foaming, emulsifying, demulsifying, solubilizing, wetting, thickening, metal sequestering, vesicle forming and phase dispersion make them suitable for use in pharmaceuticals, cosmetics and food. Pseudomonas species are also able to synthesize biopolymers known as PHAs that present flexible or elastomeric properties that are useful for biomedical applications and for the manufacture of packaging material. The main advantage of RL and PHAs is that they are biodegradable and are potentially able to substitute for chemical detergents and plastics. However, a drawback to their widespread use is the economics of their production and the scarce information about their biotic and abiotic toxicities. Rhamnolipids and PHAs can be produced by several Pseudomonas species including some that are non-pathogenic; furthermore, the biosynthetic pathways of both compounds are closely related, and their simultaneous microbial production might lead to a feasible strategy to make their commercial exploitation successful. (C) 2010 Elsevier Ltd. All rights reserved.