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A biosurfactant-producing bacterium (Staphylococcus sp. strain 1E) was isolated from an Algerian crude oil contaminated soil. Biosurfactant production was tested with different carbon sources using the surface tension measurement and the oil displacement test. Olive oil produced the highest reduction in surface tension (25.9 dynes cm(-1)). Crude oil presented the best substrate for 1E biosurfactant emulsification activity. The biosurfactant produced by strain 1E reduced the growth medium surface tension below 30 dynes cm(-1). This reduction was also obtained in cell-free filtrates. Biosurfactant produced by strain 1E showed stability in a wide range of pH (from 2 to 12), temperature (from 4 to 55 °C) and salinity (from 0 to 300 g l(-1)) variations. The biosurfactant produced by strain 1E belonged to lipopeptide group and also constituted an antibacterial activity againt the pathogenic bacteria such as Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Bacillus subtilis. Phenanthrene solubility in water was enhanced by biosurfactant addition. Our results suggest that the 1E biosurfactant has interesting properties for its application in bioremediation of hydrocarbons contaminated sites.

Aims:  To characterize the white rot fungus Perenniporia tephropora with respect to its laccase and to test its ability to decolourize synthetic dyes. Methods and Results:  Under the culture conditions utilized, P. tephropora produced one laccase isozyme, which was purified to electrophoretic homogeneity by ammonium sulfate precipitation, size‐exclusion chromatography and anion‐exchange chromatography. The protein was monomeric with a molecular mass of 63 kDa (SDS–PAGE) and had an isoelectric point of 3·3. The N‐terminal amino acid sequence was SIGPVADLTVTNANI and the highest similarity value was found to the laccase from Lentinus tigrinus (86·6%). The optimum pH of the enzyme varied and was substrate dependent. It was 4·0 and 5·0 for 2,6‐dimethoxyphenol (DMP) and 2,2′‐azino‐di(3‐ethyl‐benzthiazoline‐6‐sulfonate) (ABTS), respectively. Under standard assay conditions, Km values of the enzyme were 7·3 and 0·4 mmol l−1 towards DMP and ABTS, respectively. The laccase was inhibited by NaN3, EDTA and p‐coumarate but not by SDS and NaBr. Laccase was stable in the presence of some metal ions such as Cu2+, Co2+, Ca2+, Cd2+, Mg2+, Mn2+, Mo2+, Ni2+, Li+ and Al3+. The crude enzyme as well as the purified laccase was able to decolourize dyes from the textile industries, including remazol brilliant blue R, neolane blue and neolane pink. However, several other dyes were partially or not decolourized. In the presence of 1‐hydroxybenzotriazole as mediator, only the decolourization of neolane yellow was achieved, while the decolourization of most of the dyes was just slightly improved. Significance and Impact of the Study:  This study is the first report on the purification and the characterization of the laccase from the white rot fungus P. tephropora. The high levels of laccase secreted by this fungal strain as well as its stability suggest that it could be a useful tool for environmental applications.