Indigenous fungi isolated from soil of a former gasworks site were investigated in submerged cultures with pyrene as the sole carbon source. Five fungal strains capable of degrading pyrene included one strain of Trichoderma harzianum and four strains with characteristics of the genus Penicillium. These are identified as Penicillium simplicissimum, Penicillium janthinellum, Penicillium funiculosum and Penicillium terrestre. A maximum of 75% of 50 mg l(-1) and 67% of 100 mg l(-1) of pyrene was removed by the fast degrading strain P. terrestre at 22 degrees C during 28 days of incubation. The slower degrader P. janthinellum was able to remove 57% of 50 mg l(-1) and about 31.5% of 100 mg l(-1) pyrene. Degradation of pyrene is directly correlated with biomass development. To the best of our knowledge, this is the first time that fungi have been reported to use pyrene as the sole carbon and energy source. They may be ideal candidates for effective bioremediation of polycyclic aromatic hydrocarbons.

An unknown Gram-positive, catalase-positive, facultatively anaerobic, non-spore-forming, coccus-shaped bacterium originating from sediment was characterized using phenotypic, molecular chemical and molecular phylogenetic methods. Chemical studies revealed the presence of a cell-wall murein based on ll-diaminopimelic acid (type ll-Dpm-glycine1), a complex mixture of saturated, monounsaturated and iso- and anteiso-methyl-branched, non-hydroxylated, long-chain cellular fatty acids and tetrahydrogenated menaquinones with eight isoprene units [MK-8(H4)] as the major respiratory lipoquinone. This combination of characteristics somewhat resembled members of the suborder Micrococcineae, but did not correspond to any currently described species. Comparative 16S rRNA gene sequencing confirmed that the unidentified coccus-shaped organism is a member of the Actinobacteria and represents a hitherto-unknown subline related to, albeit different from, a number of taxa including Intrasporangium, Janibacter, Terrabacter, Terracoccus and Ornithinicoccus. Based on phenotypic and phylogenetic considerations, it is proposed that the unknown bacterium originating from lake sediment be classified as a new genus and species, Arsenicicoccus bolidensis gen. nov., sp. nov. (type strain CCUG 47306T=DSM 15745T).

Five indigenous fungal strains with characteristics of the genus Penicillium capable of degrading and utilizing pyrene, as sole carbon source were isolated from soil of a former gas work site. Two strains were identified as Penicillium ochrochloron. One of the strains was able to degrade a maximum of 75% of 50 mg l(-1) pyrene at 22 degrees C during 28 days of incubation. The presence of pyrene in the medium resulted in an aggregation of hyphae into pellets by the two Penicillium ochrochloron strains. Formation of pellets was observed after 48 h of incubation with difference in size and texture between the two strains. This indicated the individual variation within the same genus of fungi. However, remaining strains did not show this behavior even though they were capable of utilizing pyrene as sole carbon source. The macro- and microscopic morphology of fungal pellets was studied using scanning electron microscopy. It was found that the addition of varying concentration of pyrene ranging from 10 to 50 mg l(-1) in the medium influenced shape and structure of the mycelial pellets. A two-fold increase in hyphal branching (with concomitant decrease in the average hyphal growth unit) was observed at a concentration of 10mg l(-1). The relevance of fungal growth and morphology for bioremediation of polycyclic aromatic hydrocarbons (PAHs) contaminated sites are discussed.

A ten member microbial consortium (AS) consisting of eight phenol-degrading and two non-phenol-degrading strains of bacteria was developed and maintained in a fed-batch reactor by feeding 500 mg l(-1) phenol for four years at 28 +/- 3 degrees C. The consortium could degrade 99% of 500 mg l(-1) phenol after 24 hours incubation with a biomass increase of 2.6 x 10(7) to 4 x 10(12) CFU ml(-1). Characterization of the members revealed that it consisted of 4 principal genera, Bacillus, Pseudomonas, Rhodococcus, Streptomyces and an unidentified bacterium. Phenol degradation by the mixed culture and Bacillus subtilis, an isolate from the consortium was compared using a range of phenol concentrations (400 to 700 mg l(-1)) and by mixing with either 160 mg l(-1) glucose or 50 mg l(-1) of 2,4-dichlorophenol in the medium. Simultaneous utilization of unrelated mixed substrates (glucose/2,4-dichlorophenol) by the consortium and Bacillus subtilis, indicated the diauxic growth pattern of the organisms. A unique characteristic of the members of the consortia was their ability to oxidize chloro aromatic compounds via meta pathway and methyl aromatic compounds via ortho cleavage pathway. The ability of a large membered microbial consortia to maintain its stability with respect to its composition and effectiveness in phenol degradation indicated its suitability for bioremediation applications.