Solvent-Augmented Mineralization of Pyrene by a Mycobacterium sp.

摘要: The biodegradation of polycyclic aromatic hydrocarbon pollutants is constrained, in part, by their solid physical state and very low water solubility. Searching for ways to overcome these limitations, we isolated from soil a bacterium capable growing on pyrene as sole source carbon energy. Acid-fast stain, morphology, fatty acid profile identified it Mycobacterium sp. In mineral salts solution, the isolate mineralized 50% 250-(mu)g/ml concentration [(sup14)C]pyrene 2 3 days. Detergent below critical micelle increased mineralization rate 154%, but above concentration, detergent severely inhibited mineralization. water-miscible solvent polyethylene glycol was inhibitory. hydrophobic solvents heptamethylnonane, decalin, phenyldecane, diphenylmethane were also inhibitory at several concentrations tested, addition paraffin oil, squalene, squalane, tridecylcyclohexane, cis-9-tricosene 0.8% (vol/vol) doubled rates without being utilized themselves. found have high cell surface hydrophobicity adhered emulsified droplets that contained dissolved pyrene, facilitating its mass transfer degrading bacteria. Cells physically adhering metabolized 8.5 times fast cells suspended aqueous medium. An enhanced compounds microorganisms suitable might allow development solvent-augmented techniques use or slurry-type bioreactors.