Two glycolipids increase in the bioremediation of halogenated aromatic compounds

Two bacterial glycolipids were applied for the bioremediation of mono-halogenated aromatic compounds in soil. 4-Chloro-1-naphthol (CN) and 3-chlorodiphenylamine (CDA) were rinsed from a polluted soil sample using a biosurfactant, rhamnolipid. Deemulsification by pH adjustment to 4.0 resulted in about 90% recovery of CN and CDA in an organic solvent fraction which was finally solidified by evaporation. For the bioremediation of the aqueous phase, a bacterial glycoglycerolipid, di-O-12-methyl-tetradecanoyl-3-O-beta-D-galactopyranosyl-sn-glycerol was used to decrease the level of cellular damage induced by the effects of oxygen radical of the intermediate metabolites of CN and CDA. The glycoglycerolipid at a concentration of 100 mg/l increased the cellular resistance to those CN and CDA approximately three fold. Instead of the addition of purified glycoglycerolipid, a 0.1%-volume addition of the culture supernatant of a glycoglycerolipid producer to active sludge was also effective.