Effect of rhamnolipid (biosurfactant) structure on solubilization and biodegradation of n-alkanes

Journal Article · Thu Jun 01 04:00:00 EDT 1995 · Applied and Environmental Microbiology

OSTI ID:96607

Zhang, Y; Miller, R M ^[1]

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1. Univ. of Arizona, Tucson, AZ (United States)

A study to quantify the effect of rhamnolipid biosurfactant structure on the degradation of alkanes by a variety of Pseudomonas isolates was conducted. Two dirhamnolipids were studied, a methyl ester form (dR-Me) and an acid form (dR-A). These rhamnolipids have different properties with respect to interfacial tension, solubility, and charge. For example, the interfacial tension between hexadecane and water was decreased to <0.1 dyne/cm by the dR-Me but was only decreased to 5 dyne/cm by the dR-A. Solubilization and biodegradation of two alkanes in different physical states, liquid and solid, were determined at dirhamnolipid concentrations ranging from 0.01 to 0.1 mM (7 to 70 mg/liter). The dR-Me markedly enhanced hexadecane (liquid) and octadecane (solid) degradation by seven different Pseudomonas strains. For an eighth strain tested, which exhibited extremely high cell surface hydrophobicity, hexadecane degradation was enhanced but octadecane degradation was inhibited. The dR-A also enhanced hexadecane degradation by all degraders but did so more modestly than the dR-Me. For octadecane, the dR-A only enhanced degradation by strains with low cell surface hydrophobicity. 19 refs., 5 figs., 2 tabs.

• DOE Contract Number: FG03-93ER61526
• OSTI ID: 96607
• Journal Information: Applied and Environmental Microbiology, Journal Name: Applied and Environmental Microbiology Journal Issue: 6 Vol. 61; ISSN AEMIDF; ISSN 0099-2240
• Country of Publication: United States
• Language: English

Related Subjects

56 BIOLOGY AND MEDICINE
APPLIED STUDIES
ALKANES
BIODEGRADATION
BIOLOGICAL EFFECTS
BIOLOGICAL PATHWAYS
PSEUDOMONAS
SURFACTANTS