Bacteria belonging to the genus Paenibacillus were isolated by enrichment from petroleum-hydrocarbon-contaminated sediment and salt marsh rhizosphere using either naphthalene or phenanthrene as the sole carbon source, and were characterized using phenotypic, morphological and molecular techniques. The isolates were grouped by their colony morphologies and polyaromatic hydrocarbon-degradation patterns. Phenanthrene-degrading isolates produced mottled colonies on solid media and were identified as P. validus by fatty acid methyl ester and 16S rRNA gene sequence analyses. In contrast, the naphthalene-degrading isolates with mucoid colony morphology were distantly related to Paenibacillus validus, according to fatty acid methyl ester and 16S rRNA gene sequence analyses. The predominant fatty acids of the mucoid isolates were 15 :0 anteiso, 16 :1ω11c, 16 :0 and 17 :0 anteiso, constituting, on average, 505, 120, 112 and 65 % of the total, respectively. The GMC contents of their DNA ranged from 47 to 52 mol %. The 16S rDNA sequence analysis revealed the highest (a 94 %) similarity to P. validus. In addition, phylogenetic analyses based on 16S rDNA sequences showed that the mucoid isolates formed a distinct cluster within Paenibacillus. DNA-DNA hybridization experiments showed only a 6 % DNA similarity between the type strain of P. validus and mucoid strain PR-N1. On the basis of the morphological, phenotypic and molecular data, the naphthalene-degrading isolates merit classification as a new Paenibacillus species, for which the name Paenibacillus naphthalenovorans sp. nov. is proposed, with PR-N1 T (l ATCC BAA-206 T l DSM 14203 T ) as the type strain.

The purpose of this study was to determine the ability of nonbasidiomycete soil fungi to oxidize pyrene (four rings) and benzo[a]pyrene (BaP) (five rings). Fungi were isolated from five different soils in which the polycyclic aromatic hydrocarbon content ranged from 0.8 to 80 micrograms/g dry soil. Approximately 50% of the isolates in all sites were able to oxidize pyrene. The pyrene-oxidizing species belonged to all fungal divisions except basidiomycetes. The most common were Penicillium spp. of the subgenus Furcatum and these dominated the more contaminated soils. Penicillium janthinellum and Syncephalastrum racemosum exhibited the most rapid rates of pyrene oxidation. The major pyrene metabolites were identified by proton NMR and mass spectrometry as 1-pyrenol, 1,6- and 1,8-pyrenediol, and the 1,6-and 1,8-pyrenequinones. A high correlation was found between the ability to oxidize pyrene and BaP. As with pyrene, approximately 50% of the fungal isolates tested oxidized BaP to 9-hydroxy-BaP. Eighty percent of the pyrene-oxidizing strains were also able to metabolize BaP.

At present, there is little information on the optimization of the degradation of polycyclic aromatic hydrocarbons (PAH) by deuteromycete filamentous fungi, a reaction catalyzed by cytochrome P450 monooxygenases. We utilized response-surface methodology to determine the optimal growth conditions for the oxidation of the PAH pyrene by Penicillium janthinellum SFU403, with respect to the variables glucose concentration, nitrate concentration and bioconversion time. Models were derived for the relationship between the variables tested and the level of the pyrene oxidation products. 1-pyrenol (1-PY) and pyrenequinones (PQ). Production of 1-PY and PQ were optimized by the same glucose and nitrate concentrations: 2.5% glucose and 1.5% sodium nitrate. The optimized 1-PY and PQ bioconversion times were 71 h and 73 h respectively. These conditions improved the yield of 1-PY by fivefold and PQ were more than 100-fold higher than the baseline levels obtained in this study. The optimized PQ yield represented 95% of the initial pyrene, thus the total optimised pyrene bioconversion to 1-PY and PQ was approximately 100%. Concentrations of glucose exceeding 4.0% repressed pyrene hydroxylation. Pyrene hydroxylation occurred almost exclusively during the deceleration phase of culture growth.

Treatment of dredged sediments contaminated by polyaromatic hydrocarbons (PAHs) is a significant problem in the New York/New Jersey (NY/NJ) Harbor. 0.5 m--scale slurry-phase bioreactors were used to determine whether bioaugmentation with a PAH-degradative bacterial consortium, or with the salt marsh grass S. alterniflora, could enhance the biodegradation of PAHs added to dredged estuarine sediments from the NY/NJ Harbor. The results were compared to biodegradation effected by the indigenous sediment microbial community. Sediments were diluted 1:1 in tap water and spiked to a final concentration of 20 rng/kg dry weight sediment of phenanthrene, anthracene, acenaphthene, fluorene, fluoranthene, and pyrene. The sediment slurry was then continuously sparged with air over 3 months. In all bioreactors a rapid reduction. of greater than 95% of the initial phenanthrene, acenaphthene, and fluorene occurred within 14 days. Pyrene and fluoranthene reductions of 70 to 90% were achieved by day 77 of treatment. Anthracene was more recalcitrant and reductions ranged from 30 to 85%. Separate experiments showed that the sediment microbial communities mineralized 14C-pyrene and 14C-phenanthrene. PAH degradation, and the number of phenanthrene-degrading bacteria, were not enhanced by microbial or plant bioaugmentation. These data demonstrate that bioaugmentation is not required to effect efficient remediation of PAR-contaminated dredged sediments in slurry-phase bioreactors.