title: Degradation and mineralization of high-molecular-weight polycyclic aromatic hydrocarbons by defined fungal-bacterial cocultures.
abstract: This study investigated the biodegradation of high-molecular-weight polycyclic aromatic hydrocarbons (PAHs) in liquid media and soil by bacteria (Stenotrophomonas maltophilia VUN 10,010 and bacterial consortium VUN 10,009) and a fungus (Penicillium janthinellum VUO 10, 201) that were isolated from separate creosote- and manufactured-gas plant-contaminated soils. The bacteria could use pyrene as their sole carbon and energy source in a basal salts medium (BSM) and mineralized significant amounts of benzo[a]pyrene cometabolically when pyrene was also present in BSM. P. janthinellum VUO 10,201 could not utilize any high-molecular-weight PAH as sole carbon and energy source but could partially degrade these if cultured in a nutrient broth. Although small amounts of chrysene, benz[a]anthracene, benzo[a]pyrene, and dibenz[a,h]anthracene were degraded by axenic cultures of these isolates in BSM containing a single PAH, such conditions did not support significant microbial growth or PAH mineralization. However, significant degradation of, and microbial growth on, pyrene, chrysene, benz[a]anthracene, benzo[a]pyrene, and dibenz[a,h]anthracene, each as a single PAH in BSM, occurred when P. janthinellum VUO 10,201 and either bacterial consortium VUN 10,009 or S. maltophilia VUN 10,010 were combined in the one culture, i.e., fungal-bacterial cocultures: 25% of the benzo[a]pyrene was mineralized to CO(2) by these cocultures over 49 days, accompanied by transient accumulation and disappearance of intermediates detected by high-pressure liquid chromatography. Inoculation of fungal-bacterial cocultures into PAH-contaminated soil resulted in significantly improved degradation of high-molecular-weight PAHs, benzo[a]pyrene mineralization (53% of added [(14)C]benzo[a]pyrene was recovered as (14)CO(2) in 100 days), and reduction in the mutagenicity of organic soil extracts, compared with the indigenous microbes and soil amended with only axenic inocula.
authors.affiliation: Centre for Bioprocessing and Food Technology, Victoria University of Technology, Werribee Campus, Melbourne, Australia 8001.
authors.forename: S
authors.initials: S
authors.lastname: Boonchan
authors.forename: M L
authors.initials: ML
authors.lastname: Britz
authors.forename: G A
authors.initials: GA
authors.lastname: Stanley
mesh_terms: D001564:Benzo(a)pyrene / Q000378:metabolism*; D001673:Biodegradation, Environmental; D018920:Coculture Techniques; D003407:Creosote; D009152:Mutagenicity Tests; D010407:Penicillium / Q000378:metabolism*; D011084:Polycyclic Aromatic Hydrocarbons / Q000378:metabolism*; D012988:Soil Microbiology; D012989:Soil Pollutants; D020615:Stenotrophomonas maltophilia / Q000378:metabolism*
chemical_list: D011084:Polycyclic Aromatic Hydrocarbons; D012989:Soil Pollutants; D001564:Benzo(a)pyrene; D003407:Creosote