title: Production of rhamnolipids in solid-state cultivation: Characterization, downstream processing and application in the cleaning of contaminated soils.
abstract: Pseudomonas aeruginosa UFPEDA 614 produced a rhamnolipid biosurfactant when grown on sugarcane bagasse impregnated with a solution containing glycerol. Biosurfactant levels reached 40 g of rhamnolipid per kilogram of dry initial substrate after 12 days. On the basis of the volume of liquid used, the biosurfactant levels were similar to those obtained in submerged liquid culture of a medium identical to the impregnating solution. The properties of the biosurfactant were very similar to those obtained with rhamnolipids produced in submerged culture, with a critical micelle concentration of 46.8 mg/L and an emulsification index at 24 h of over 90% against gasoline. The surface properties were maintained after autoclaving of the fermented solids, meaning that it is possible to minimize safety risks by killing the producing organism with a heat treatment of the solids prior to product extraction. The biosurfactant was used in the washing of soils contaminated with gasoline. An aqueous biosurfactant solution was 3.2-fold more efficient than water in leaching organic material from the soil, demonstrating the viability of application of rhamnolipids in the bioremediation of soils contaminated with gasoline.
authors.affiliation: Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Brazil.
authors.forename: Doumit
authors.initials: D
authors.lastname: Camilios Neto
authors.forename: Joel Alexandre
authors.initials: JA
authors.lastname: Meira
authors.forename: Elaine
authors.initials: E
authors.lastname: Tiburtius
authors.forename: Patrício Peralta
authors.initials: PP
authors.lastname: Zamora
authors.forename: Cryshelen
authors.initials: C
authors.lastname: Bugay
authors.forename: David Alexander
authors.initials: DA
authors.lastname: Mitchell
authors.forename: Nadia
authors.initials: N
authors.lastname: Krieger
mesh_terms: D001673:Biodegradation, Environmental; D019149:Bioreactors; D002482:Cellulose / Q000378:metabolism; D004355:Drug Stability; D005742:Gasoline; D006017:Glycolipids / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D008823:Micelles; D011550:Pseudomonas aeruginosa / Q000378:metabolism*; D012989:Soil Pollutants / Q000378:metabolism*; D013499:Surface Properties; D013501:Surface-Active Agents / Q000737:chemistry / Q000378:metabolism*; D013696:Temperature
chemical_list: D005742:Gasoline; D006017:Glycolipids; D008823:Micelles; D012989:Soil Pollutants; D013501:Surface-Active Agents; C418382:rhamnolipid; D002482:Cellulose; C027433:bagasse