http://http://dspace.unitus.it:80 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Mon, 20 May 2013 14:25:25 GMT 2013-05-20T14:25:25Z http://hdl.handle.net/2067/1200 Title: In vivo and in vitro degradation of aromatic contaminants by white rot fungi. A case study: Panus tigrinus CBS 577.79 Authors: Covino, Stefano Description: Dottorato di ricerca in Evoluzione biologica e biochimica Wed, 17 Feb 2010 23:00:00 GMT http://hdl.handle.net/2067/1200 2010-02-17T23:00:00Z http://hdl.handle.net/2067/1408 Title: Effect of mobilizing agents on mycoremediation and impact on the indigenous microbiota Authors: Giubilei, Maria Angela; Leonardi, Vanessa; Federici, Ermanno; Covino, Stefano; Sasek, Vaclav; Novotny, Cenek; Federici, Federico; D'Annibale, Alessandro; Petruccioli, Maurizio Abstract: BACKGROUND: Mobilizing agents (MAs) have been suggested to improve the fungal degradation of polycyclic aromatic hydrocarbons (PAHs) in soil. Three different MAs (Tween 20, Tween 80 and soybean oil) were investigated for their ability to stimulate contaminant degradation by either Phlebia sp. DABAC 9 or Allescheriella sp. DABAC1 in a soil spiked with amixture of PAHs. RESULTS: Phlebia sp. and Allescheriella sp. markedly differed in their growth capabilities under non-sterile conditions and withoutMAs (3.0 versus 0.1 μg ergosterol g−1 soil, respectively). However, soybean oil led to a 35-fold increase of Allescheriella sp. growth. Contaminant degradations by Phlebia sp. DABAC 9 and Allescheriella sp. DABAC 1 were best supported by soybean oil and Tween 20, respectively. Enumeration of cultivable bacteria and denaturing gradient gel electrophoresis (DGGE) analysis of PCR-amplified 16S rRNA showed that microbial density and biodiversity were positively affected by the mycoremediation especially with Allescheriella sp., the use of which led to an evident detoxification. CONCLUSIONS: Allescheriella sp. DABAC 1 appears to be a promising strain in the remediation of PAH-contaminated soils. The different response of the two fungi to MAs addition confirms the stringent need for a preliminary lab-scale assessment of fungus/MA combinations prior to application. Description: L'articolo è disponibile sul sito dell'editore: http://www.onlinelibrary.wiley.com Wed, 31 Dec 2008 23:00:00 GMT http://hdl.handle.net/2067/1408 2008-12-31T23:00:00Z http://hdl.handle.net/2067/1411 Title: Kinetic and redox properties of MnP II, a major manganese peroxidase isoenzyme from Panus tigrinus CBS 577.79. Authors: Petruccioli, Maurizio; Frascono, Marco; Quaratino, Daniele; Covino, Stefano; Favero, Gabriele; Mazzei, Franco; Federici, Federico; D'Annibale, Alessandro Abstract: A manganese peroxidase (MnP) isoenzyme from Panus tigrinus CBS 577.79 was produced in a benchtop stirred-tank reactor and purified to apparent homogeneity. The purification scheme involving ultrafiltration, affinity chromatography on concanavalin–A Sepharose, and gel filtration led to a purified MnP, termed ‘‘MnP II,’’ with a specific activity of 288 IU mg-1 protein and a final yield of 22%. The enzyme turned out to be a monomeric protein with molecular mass of 50.5 kDa, pI of 4.07, and an extent of N-glycosylation of about 5.3% of the high-mannose type. The temperature and pH optima for the formation of malonate manganic chelates were 45°C and 5.5, respectively. MnP II proved to be poorly thermostable at 50 and 60°C, with half-lives of 11 min and 105 s, respectively. Km values for H2O2 and Mn2+ were 16 and 124 lM, respectively. Although MnP II was able to oxidize veratryl alcohol and to catalyze the Mn2+ -independent oxidation of several phenols, it cannot be assigned to the versatile peroxidase family. As opposed to versatile peroxidase oxidation, veratryl alcohol oxidation required the simultaneous presence of H2O2 and Mn2+; in addition, low turnover numbers and Km values higher than 300 lM characterized the Mn2+ -independent oxidation of substituted phenols. Kinetic properties and the substrate specificity of the enzyme markedly differed from those reported for MnP isoenzymes produced by the reference strain P. tigrinus 8/18. To our knowledge, this study reports for the first time a thorough electrochemical characterization of a MnP from this fungus. Description: L'articolo è disponibile sul sito dell'editore: http://www.springerlink.com Wed, 31 Dec 2008 23:00:00 GMT http://hdl.handle.net/2067/1411 2008-12-31T23:00:00Z