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A strain of Klebsiella oxytoca BAS-10, known to produce a specific exopolysaccharide (EPS), when grown aerobically in static mode in the presence of Pd(NO3)2, generated the species Pd-EPS that was used as catalyst precursor in the aqueous biphasic treatment of some nitrocompounds with hydrogen. Nitrobenzene was hydrogenated to aniline with almost quantitative yields and the catalyst, embedded in the aqueous phase, was used with success and with near the same efficiency in three recycling experiments. In the case of 1-iodo-4-nitrobenzene only nitrobenzene was obtained while the unsaturated nitro compound β-methyl-β-nitrostyrene afforded both the corresponding oxime and the saturated nitro derivative.

A sediment sample from Venice Lagoon was found to be contaminated with 475 mg Kg(-1) polycyclic aromatic hydrocarbons (PAHs). Naphthalene was the principal pollutant at 26% of total PAHs. Two strains of Pseudomonas SN1 and SB1 were isolated from sediment amended with 2% naphthalene. 16S rRNA gene sequence analysis indicated that the two strains have about 99% nucleotide identity with strains of the genus Pseudomonas, and are very Close to Pseudomonas stutzeri. Their metabolic profiles showed significant nutritional differences, the most significant of which was that SN1 grows in marine mineral medium spiked with naphthalene and SB1 grows with biphenyl as sole carbon and energy sources. Pseudomonas sp. SN1 had a doubling time of 3.1 h with 2% naphthalene and SB1 had a doubling time of 19.5 h with 2% biphenyl. Strain SN1 oxidised naphthalene at 564 32 mg O-2 l(-1) d(-1) and SB1 oxidised biphenyl at 426 25 mg O-2 l(-1) d(-1) in respirometry reaction vessels under controlled conditions. Screening of the two strains for dioxygenase genes involved in the first step of the two hydrocarbon degradation pathways, by polymerase chain reaction, showed naphthalene dioxygenase in SN1 and biphenyl dioxygenase in SB1. The strains each have a different catechol 2,3-dioxygenase responsible for cleavage of the aromatic ring. (c) 2006 Elsevier Ltd. All rights reserved.