http://http://dspace.unitus.it:80 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. 2013-05-23T04:34:48Z http://hdl.handle.net/2067/1533 Title: Organic matter transformation and detoxification in dry olive mill residue by the saprophytic fungus Paecilomyces farinosus Authors: Sampedro, Inmaculada; Cajthaml, Tomáš; Marinari, Sara; Petruccioli, Maurizio; Grego, Stefano; D'Annibale, Alessandro Abstract: Dry olive mill residue (DOR), the by-product of the two-phase extraction process, is very rich in organic matter and nutritionally relevant cations. For this reason, the agronomic use of this waste has been suggested although DOR exhibits significant phytotoxicity. The objective of this study was to investigate the impact of Paecilomyces farinosus on both organic matter modification and detoxification of this waste.Humification ratio in DOR colonized by the fungus for 20 weeks was increased by about 65% with respect to the abiotic control and humification index reached 0.38, a value that characterizes well-humified materials. High performance size-exclusion chromatography of humic acids from fungal cultures showed a marked increase in both weight-averaged and number-averaged molecular weights with respect to abiotic controls. Water-soluble phenols were reduced by 45% in 20-week-old P. farinosus cultures on DOR and mass-balance ultra-filtration showed that the relative abundance of the molecular weight fraction of phenols above 30 kDa increased from 31 to 72% suggesting the occurrence of polymerization.Experiments performed with alfalfa grown on soils containing 2.5% (w/w) of abiotic controls and fungaltreated DOR showed that phytotoxicity was totally suppressed in the waste that underwent fungal treatment. Description: L'articolo è disponibile sul sito dell'editore: http://www.sciencedirect.com 2010-12-31T23:00:00Z http://hdl.handle.net/2067/1412 Title: Immobilized inocula of white-rot fungi accelerate both detoxification and organic matter transformation in two-phase dry olive-mill residue Authors: Sampedro, Inmaculada; Cajthaml, Tomáš; Marinari, Sara; Stazi, Silvia Rita; Grego, Stefano; Petruccioli, Maurizio; Federici, Federico; D'Annibale, Alessandro Abstract: The potential use for agronomic purposes of dry olive-mill residue (DOR), solid waste from the olive oil two-phase extraction process, might be impaired by its phytotoxicity. Although fungal treatments can detoxify DOR, long times are required for these processes. The objective of this study was to assess whether the addition of immobilized fungal inocula to DOR might improve colonization rates, thus reducing the time necessary for its detoxification and bioconversion. Inocula of Panus tigrinus CBS 577.79 and Phlebia sp. DABAC 9 immobilized on either chopped maize stalks or polyurethane sponge (PS) led to higher removals of both phenols and phytotoxicity from DOR than free inocula after 4 weeks of incubation. Best dephenolization (85%) was with PS-immobilized Phlebia sp., the use of which reduced germinability inhibition of Lepidium sativum and Lactuca sativa by 80 and 71.4%, respectively. Regardless of the type of inoculant, a low degree of humification was obtained. 2008-12-31T23:00:00Z http://hdl.handle.net/2067/1410 Title: Short-term impact of dry olive mill residue addition to soil on the resident microbiota Authors: Sampedro, Inmaculada; Giubilei, Maria Angela; Cajthaml, Tomáš; Federici, Ermanno; Federici, Federico; Petruccioli, Maurizio; D'Annibale, Alessandro Abstract: The short-term response of the resident soil bacterial and fungal communities to the addition of 5% (w/w) of either dry olive mill residue (DOR), DOR treated with Phlebia sp. (PTDOR) or DOR previously extracted with water (WEDOR) was investigated. As opposed to bacteria, the diversity of fungi increased upon the amendments as assessed by denaturing gradient gel electrophoresis of 18S rDNA. Over the first 30 days, phospholipid fatty acids analyses indicated a gradual decrease in the relative abundances of Gram+ bacteria (from 44.8% to 37.9%) and a concomitant increase of Gram- bacteria (from 37.3% to 51.2%) in DOR-amended soil. A considerable increase in the fungal/bacterial ratio was observed after 7 days in DOR, WEDOR and PTDOR-amended soils with respect to the control (0.316, 0.165 and 0.265, respectively, vs. 0.011). The overall microbial activity was stimulated by the amendments as indicated by the higher activity levels of both dehydrogenase and fluorescein diacetate hydrolase. These results indicate that DOR at the application level examined is not toxic on soil microorganisms. Description: L'articolo é disponibile sul sito dell'editore: http://www.sciencedirect.com 2008-12-31T23:00:00Z http://hdl.handle.net/2067/1576 Title: Solid-state cultures of Fusarium oxysporum transform aromatic components of olive-mill dry residue and reduce its phytotoxicity Authors: Sampedro, Inmaculada; D'Annibale, Alessandro; Ocampo, Juan Antonio; Garcia-Romera, Inmaculada Abstract: The present study mainly investigated the ability of solid-state cultures of the non-pathogenic Fusarium oxysporum strain BAFC 738 to transform aromatic components to reduce the phytotoxicity in olive-mill dry residue (DOR), the waste from the two-phase manufacturing process. Lignin, hemicellulose, fats and water-soluble extractives contents of DOR colonized by the fungus for 20 weeks were reduced by 16%, 25%, 71% and 13%, respectively, while the cellulose content increased by 25%. In addition, the ethyl acetate-extractable phenolic fraction of the waste was reduced by 65%. However, mass-balance ultra-Wltration and size-exclusion chromatography experiments suggested that the apparent removal of that fraction, mainly including 2-(3,4-dihydroxyphenyl)ethyl alcohol and 2-(4-hydroxyphenyl) ethyl alcohol, was due to polymerization. Mn-peroxidase and Mn-independent peroxidase activities were found in F. oxysporum solid-state cultures, while laccase and aryl alcohol oxidase activities were not detected. Tests performed with seedlings of tomato (Lycopersicum esculentum L.), soybean (Glycine maximum Merr.), and alfalfa (Medicago sativa L.) grown on soils containing 6% (w/w) of bioconverted DOR (kg soil)¡1 showed that the waste’s phytotoxicity was removed by 20 weeks-old fungal cultures. By contrast, the same material exhibited a high residual toxicity towards lettuce (Lactuca sativa L.). Description: L'articolo é disponibile sul sito dell'editore: http://www.sciencedirect.com 2006-12-31T23:00:00Z