Papers by Maurizio Petruccioli
International Biodeterioration & Biodegradation, 2014
ABSTRACT An experimental biofuel wood chip storage site was studied, as a potential fungal “reser... more ABSTRACT An experimental biofuel wood chip storage site was studied, as a potential fungal “reservoir,” by means of quantitative and qualitative assessments of airborne fungal spores. Fungal load in the bio-aerosol, determined through active and passive methods, declined with the distance from wood piles. Occupational exposure was comparatively evaluated when two specific operational tasks, manual and mechanized handling, were performed. Under the conditions tested, the manual operators were more exposed to the airborne fungal spores (4864 ± 580 CFU m−3 air). The collected spores were identified as belonging to species of the genera Alternaria, Aspergillus, Penicillium, Fusarium, Cladosporium, Pleospora, Cochliobolus, Epicoccum, Absidia, and Trichoderma. Most prevalent were the genera Alternaria and Cladosporium, with the highest percentages of occurrence (30 and 12%, respectively). To the best of our knowledge, this is the first work reporting the identification through molecular methods of airborne fungi released during the handling of wood chip biofuel biomass.
Microbiological Research, 1995
The presence of antibiotic resistant bacteria was revealed among bacteria isolated from non carbo... more The presence of antibiotic resistant bacteria was revealed among bacteria isolated from non carbonated mineral waters bottled in plastic (PVC) and in glass containers. Heterotrophic plate count values ranged between < 10 and 4.3 x 10 3 and between < 10 and 1.2 x 10 4 colony forming units/ml for the waters bottled in PVC and glass, respectively. The greatest resistance to a single antibiotic, 39.1 % of320 isolates from mineral waters, was found for nalidixic acid. Resistance to the other antibiotics was as follows: ampicillin (26.2%), bacitracin (19.7%), cotrimoxazole (18.7%), streptomycin (15.0%), tetracycline (14.4%), gentamycin (11.6%), chloramphenicol and rifampin (9.7%). The strains resistant to two or more antibiotics (multiple antibiotic resistant, MAR) provided 51% of the total isolates. Identification of 127 MAR strains showed that in the mineral waters gram-positive cocci dominated. The second, third and fourth group of identified MAR phenotypes were, in order to importance, gram-negative nonfermentative rods, gram-positive rods and gram-negative fermentative rods. The importance of the antibiotic resistant bacteria in mineral water is discussed.
Letters in Applied Microbiology, 2004
Isolation and characterization of the glucose oxidase (GOX)-encoding gene from a Penicillium vari... more Isolation and characterization of the glucose oxidase (GOX)-encoding gene from a Penicillium variabile strain (P16) having a high level of GOX activity and comparison of its expression with that of another strain of P. variabile (NRRL 1048) characterized by low GOX activity. The gene, isolated by PCR consisted of 1818 bp encoding 605 amino acid residues. Gene expression was analysed by Northern blotting and compared with that of P. variabile NRRL 1048. The higher GOX activity of strain P16 appeared likely because of de novo mRNA synthesis. Southern blotting analyses of the genomic DNA showed that the hybridization pattern of the two strains differed for the size of hybridizing fragment detected by the probe and slightly for their signal intensity. The GOX-encoding gene of P. variabile P16 was isolated and characterized to identify the molecular bases of its high level of expression and in view of improving enzyme production by developing a process based on heterologous expression. GOX-encoding genes can be subjected to high difference in their expression levels. The P16 strain of P. variable producing large amount of GOX as well as its encoding gene might be exploited for industrial applications.
Journal of Chemical Technology & Biotechnology, 2007
Fumaric acid production by Rhizopus arrhizus from commercial hydrolysates of corn starch (i.e. gl... more Fumaric acid production by Rhizopus arrhizus from commercial hydrolysates of corn starch (i.e. glucose molasses) was studied at different initial concentrations of glucose (S) and C:N ratios (R) by performing a 3(2) factorial experiment. By using the response surface methodology and statistical analysis, fumaric acid (YF) and mycelial biomass (YX) yields, as referred to the initial concentration of glucose and fumaric acid productivity (PF), were fitted to the only significant first-order effects of S and R with mean percentage errors ranging from 11 to 15%. The resulting empiric models were used to determine the optimal values of S (100-130 g dm-3) and R (150-210 g-atom C per g-atom N) associated with YF and PF varying in the ranges 40-49% and 7-8.5 g dm-3 day-1, respectively. After establishing the validity of these data at the 95% confidence level, an optimal operating condition (S = 120 g dm-3 and R = 150) was further tested using other substrates (i.e. glucose and acid or enzymatic hydrolysates of cassava, corn and potato flours). Statistically significant improvements in the fumaric acid yield and productivity were determined with respect to the predicted values. Since the highest values of YF and PF were obtained from the acid hydrolysates of the starch-based materials and such values were also found to be insensitive to the substrate used (at a probability level of 0.05), the above operating condition might be further employed to minimise fumaric acid production costs as a function of the feedstock used.
Journal of Biotechnology, 2010
Journal of Biotechnology, 2010
Bioscience, Biotechnology, and Biochemistry, 1999
The effects of medium composition on the production of beta-glucosidase (amygdalase and linamaras... more The effects of medium composition on the production of beta-glucosidase (amygdalase and linamarase) by Penicillium aurantiogriseum P35 were studied and the medium optimized as follows (g/l of deionized water): pectin, 10.0; (NH4)2SO4, 8.0; KH2PO4, 8.0; Na2HPO4, 2.8; MgSO4.7H2O, 0.5; yeast extract, 4.0; initial pH 6.0. When grown in a bench fermenter on this medium, the fungus produced 50.5 mU of amygdalase and 9.4 mU of linamarase per ml of culture broth. Two beta-glucosidases (PGI and PGII), each having amygdalase and linamarase activities, were recovered from the culture broth and purified; their relative molecular weights, as native enzymes, were estimated to be about 247,000 and 147,000, respectively. Both enzymes showed the same optimum pH (6.0) but different optimum temperatures (55 and 60 degrees C for PGI and PGII, respectively). Thermostability (10 min at 60 degrees C) and half-life of enzyme activity (7 hours at 60 degrees C) of PGII were higher than those of PGI (10 min at 50 degrees C and 2 hours at 55 degrees C, respectively). A wide range of cyanogenic glycosides (such as tetraphyllin B, epivolkenin, gynocardin, passibiflorin, prunasin, taxiphyllin, amygdalin, lucumin, sambunigrin, dhurrin, linamarin and cardiospermin sulfate) were hydrolyzed by both enzymes.
Archives of Microbiology, 1998
Mucor circinelloides LU M40 and Penicillium aurantiogriseum P 35 produce extracellular beta-glyco... more Mucor circinelloides LU M40 and Penicillium aurantiogriseum P 35 produce extracellular beta-glycosidases that are active on the cyanogenic glycoside amygdalin. From the culture broths of M. circinelloides, only one beta-glycosidase could be identified, while two different enzymes - both having amygdalase activity - were found in culture broths of P. aurantiogriseum. The study of the mechanism of hydrolysis of the beta-bis-glycoside amygdalin with purified enzymes from the two organisms indicated a possible sequential (two-step) reaction. In all cases, the first step of hydrolysis from amygdalin to prunasin was very rapid, while the second step from prunasin to cyanohydrin was much slower. No cyanohydrin lyase activity was found in the culture broths of either fungus.
Applied and Environmental Microbiology, 2013
The antibacterial eect of dierent glucose oxidase (GOX)/glucose combinations was studied on two f... more The antibacterial eect of dierent glucose oxidase (GOX)/glucose combinations was studied on two foodpoisoning organisms, enterotoxic Escherichia coli PM 015 and Salmonella derby BP 177. Growth of E. coli in nutrient broth (NB) was clearly inhibited by 4.0 mg/ml glucose after 24 h when combined with 2.0 U/ml GOX and after 48 h when combined with 0.5 or 1.0 U/ml GOX. Salmonella derby was more resistant than E. coli, but showed clear growth inhibition only after 48 h when inoculated in tubes where 2 mg glucose/ml and 2 U GOX/ml (or 4 mg glucose/ml and 1 U GOX/ml) were combined. In order to understand if the enzyme eect on microbial growth can be attributed to hydrogen peroxide or to pH decrease as a result of the production of gluconic acid, catalase (CAT) was added to GOX/glucose system. Since CAT decomposes H 2 O 2 to H 2 O and O 2 , the antibacterial eect was ascribed to a pH decrease as a result of gluconic acid in the system.
Journal of Industrial Microbiology and Biotechnology, 2004
Jet-loop reactors (JLR) used as biological waste treatment processes introduce an additional sele... more Jet-loop reactors (JLR) used as biological waste treatment processes introduce an additional selective pressure on the natural microbial flora of the incoming effluent. Several high-performing microbial inocula were tested for winery wastewater treatment and the microbial composition was analysed. A microbial consortium was enriched and selected for use with a new type of aerobic JLR. The reactor was operated continuously for more than 1 year using winery wastewaters collected in different seasons. Chemical oxygen demand (COD) removal efficiency was on average greater than 80%, with retention times of 0.8-1 day. Microbial populations were sampled for characterisation after 6 months and at the end of the study. Isolates were identified at genus and/or species level. Almost all isolates belonged to the genera Pseudomonas and Bacillus. Saccharomyces cerevisiae was also found but no filamentous fungi. These results show that a highly adapted population develops in JLRs treating winery effluents as compared to other bioreactors. Aerobic JLRs impose a stringent selective criterion on the composition of the microbial biomass.
Coloration Technology, 2009
The present study was aimed to assess the antibacterial activity and dyeing property of the pigme... more The present study was aimed to assess the antibacterial activity and dyeing property of the pigments obtained from five fungal species, Monascus purpureus, Isaria farinosus, Emericella nidulans, Fusarium verticillioides and Penicillium purpurogenum. Pigments composed from Monascus purpureus and Penicillium purpurogenum was found to be best among the pigments extracted. The opportunistic pathogens Pseudomonas aeruginosa and Escherichia coli were found to be highly suseptiable to all the pigments extracted from the fungi. The cotton fabric and leather samples were dyed with the purified pigments and their antibacterial activity were assayed under in-vitro conditions. Post-mordant cotton fabric and leather samples exhibited maximum bacterial reduction when compared with the pre-mordant and dyed samples. In general, post-mordant fabric and leather samples dyed with Monascus purpureus pigments exhibited maximum reduction towards the pathogens tested (Pseudomonas aeruginosa (fabric 48.2%, leather 41.2%), Escherichia coli (fabric 44.6%, leather 39.6%), Aeromonas hydrophila (fabric 40.9%, leather 36.3%), Salmonella typhi (fabric 40.7%, leather 36.0%), Staphylococcus aureus (fabric 34.9%, leather 23.7%). In addition, pigment exhaustion, colour coordinates, and fastness properties of the dyed cotton fabric and leather samples were also assessed. The toxicity of the pigments was evaluated by seed germination assay. https://mc.manuscriptcentral.com/cte
Antonie van Leeuwenhoek, 2003
One-hundred and five fungal strains, belonging to 46 different species, were screened for exopoly... more One-hundred and five fungal strains, belonging to 46 different species, were screened for exopolysaccharide production. Phytopathogenicity and, in particular, inability to produce conidia, were physiological characteristics positively associated and correlated with the fungal ability to produce polysaccharides. Among the 29 positive strains, Botryosphaeria rhodina DABAC-P82 was the most interesting reaching, when grown on optimal nitrogen source and concentration (NaNO3 and 2.0 g l(-1), respectively) and culture medium pH (3.7), 17.7 g l(-1) of exopolysaccharide production after only 24 h of fermentation; yield and productivity were 0.69 g g(-1) and 0.73 g l(-1)h(-1), respectively. The purified polysaccharide was characterised as a homopolysaccharide of glucose with a molecular weight of 4.875 x 10(6) Da. Studies of structural analysis indicated the presence of beta-1,3 and beta-1,6 linkages; the EPS structure was very similar to that of scleroglucan.
Enzyme and Microbial Technology, 1997
Glucose oxidase production by the mutant M-80.10 and the parental strain of Penicillium variabile... more Glucose oxidase production by the mutant M-80.10 and the parental strain of Penicillium variabile required the same nutrient addition to the production medium. Their corresponding batch cultures in a benchtop fermenter resulted in 25.6 and 19.1 U ml−1 of glucose oxidase activity, respectively, thus showing an overproduction of the mutant strain of about one third with respect to the wild
Science of The Total Environment, 2015
Different applications of spent Agaricus bisporus substrate (SAS), a widespread agro-industrial w... more Different applications of spent Agaricus bisporus substrate (SAS), a widespread agro-industrial waste, were investigated with respect to the remediation of a historically polluted soil with Polycyclic Aromatic Hydrocarbons (PAH). In one treatment, the waste was sterilized (SSAS) prior to its application in order to assess its ability to biostimulate, as an organic amendment, the resident soil microbiota and ensuing contaminant degradation. For the other treatments, two bioaugmentation approaches were investigated; the first involved the use of the waste itself and thus implied the application of A. bisporus and the inherent microbiota of the waste. In the second treatment, SAS was sterilized and inoculated again with the fungus to assess its ability to act as a fungal carrier. All these treatments were compared with natural attenuation in terms of their impact on soil heterotrophic and PAH-degrading bacteria, fungal growth, biodiversity of soil microbiota and ability to affect PAH bioavailability and ensuing degradation and detoxification. Results clearly showed that historically PAH contaminated soil was not amenable to natural attenuation. Conversely, the addition of sterilized spent A. bisporus substrate to the soil stimulated resident soil bacteria with ensuing high removals of 3-ring PAH. Both augmentation treatments were more effective in removing highly condensed PAH, some of which known to possess a significant carcinogenic activity. Regardless of the mode of application, the present results strongly support the adequacy of SAS for environmental remediation purposes and open the way to an attractive recycling option of this waste.
Enzyme and Microbial Technology - ENZYME MICROB TECHNOL, 1995
Batch cultures of Penicillium variabile P16 were grown in a 3-1 benchtop bioreactor. Glucose oxid... more Batch cultures of Penicillium variabile P16 were grown in a 3-1 benchtop bioreactor. Glucose oxidase and catalase production was followed while varying stirrer speed and adding buffering agents. Four hundred rev min−1 appeared to be optimum to ensure good growth and best enzyme production; above this, production was reduced. Among the different chemicals (CaCO3, NaOH, and NaOH plus CaCl2) employed to counteract the pH drop in the fermentation broth, CaCO3 gave the best results. The time course of growth, enzyme activities, and gluconate production at 400 rev min−1 and using CaCO3 as neutralizing agent is reported.
Biotechnology Letters, 1994
Conidia of Penicillium variabile P16 producing glucose oxidase were immobilized in different carr... more Conidia of Penicillium variabile P16 producing glucose oxidase were immobilized in different carriers and used in repeated-batch processes. Limited free-cell growth and good mechanical stability of the carriers were obtained with Ca-alginale, agar and polyurethane sponge. During prolonged experiments, the polyurethane sponge appeared to be the best carrier in relation to glucose oxidase and catalase activities. The maximum mean volumetric
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Papers by Maurizio Petruccioli