1,721,276 research outputs found
Così gli scarti dei prodotti agroindustriali possono dare l’elisir dell’eterna giovinezza
No full textTrattasi di un articolo divulgativo sul quotidiano La Repubblica nel quale vengono evidenziati i potenziali vantaggi per la salute umana di un riciclo di alcune preziose componenti dei residui agroindustrial
Use of carbon and energy balances in the study of the anaerobic metabolism of Enterobacter aerogenes at variable starting glucose concentrations
No full textThe anaerobic metabolism of Enterobacter aerogenes was studied in batch culture at increasing initial glucose levels (9.0< So <72 g l–1)
Thermodynamic study and optimization of hydrogen production by Enterobacter aerogenes
No full text10102) utilizing starch hydrolysate as substrate. An optimum pH range corresponding to 6.1– 6.6 is the main evidence of
batch runs carried out at di3erent pHs. An optimum value of temperature corresponding to 40◦C is experimentally determined
by means of batch fermentation runs carried out at di3erent operative temperatures. A thermodynamic study, which was
performed developing the Arrhenius approach, allows the estimation, for both fermentation and thermal inactivation, of the
activation enthalpies (67.3 and 118:1 kJ mol−1) and of the correlated entropies (−0:087 and −0:46 kJ mol−1 K−1). ? 2001
International Association for Hydrogen Energy
Microbial, Corrosion
No full textMicrobial corrosion refers, by definition, to the deterioration of materials caused, directly or indirectly, by bacteria, algae, moulds or fungi, individually or in combination. In particular, degradation of metallic structures derives from the activity of a wide variety of microorganisms either directly participating in electrochemical reactions on the metal surface or producing aggressive metabolites capable of making the environment corrosive. A wide range of microorganisms may be involved in corrosion processes such as:
chemical attack of metals, concrete and other materials, by means of the by-products of microbe metabolism e.g. sulphuric and carbonic acids, hydrogen sulphide or ammonia;
attack of metal by a process in which the corrosion reaction is sustained by the combined action of microbes and metal or by a combination of bacteria;
depassivation of metal surfaces and induction of corrosion cells;
depolarization of cathodic reaction;
microbial attack of organic materials (e.g. paint coatings, plastic linings), degradation of inhibitors, conversion of natural inorganic compound (e.g. sulphur)
Estrogen receptor activation protects against TNFa-induced endothelial dysfunction
No full textLack of estrogen is a cause of cardiovascular disease in men and postmenopausal women. We examined the effects of estrogen receptors (ERs) activation/inactivation on endothelial cells subjected to tumor necrosis factor (TNF)α, which is involved in vascular disease pathogenesis. Endothelial nitric oxide synthase (eNOS) and matrix metalloproteinases (MMP)-9 expression, as well as protein kinase B (PKB) activation were evaluated as markers of endothelial dysfunction. TNFα induces eNOS and MMP-9 expression and PKB activation. ER activation by apigenin, a non-steroidal compound with estrogen-like activity mediated through ER binding-dependent pathways, counteracts these effects. These effects are reversed by classic (ERα and ERβ) and non-classic (GPR30) ER inhibitors (ICI182, 780 and PTX, respectively). Our data suggest that ER activation counteracts endothelial dysfunction induced by TNFα. The use of ER activators, such as apigenin, may represent a strategy to prevent vascular disease associated with endothelial dysfunction, while avoiding the feminizing effects of estrogens
Optimization study and modelling of an entrapped-cell contactor for alcohol fermentation
No full textA general model, previous proposed for entrapped-cell Rotating Biological Surface reactors provided with spongy supports has been improved to take into account limitations in mass transfer and substrate inhibition effects coming from increases in support surface per unit volume and in feed concentration, respectively
Mathematical modelling and optimization of hydrogen continuous production in a fixed bed bioreactor
No full textThe purpose of this paper is to investigate, both theoretically and experimentally, hydrogen production from agro-industrial by-products
using a continuous bioreactor packed with a mixture of spongy and glass beads and inoculated with Enterobacter aerogenes. Replicated
series of experimental runs were performed to study the e6ects of residence time on hydrogen evolution rate and to characterize the
critical conditions for the wash out, as a function of the inlet glucose concentration and of the 7uid super'cial velocity. A further series of
experimental runs was focused on the e6ects of both residence time and inlet glucose concentration over hydrogen productivity. A kinetic
model of the process was developed and showed good agreement with experimental data, thus representing a potential tool to design a
large-scale fermenter. In fact, the model was applied to the optimal design of a bioreactor suitable of feeding a phosphoric acid fuel cell
of a target power
The effect of citric acid on the phenolic contents of olive oil
No full textResponse surface methodology was used to optimise the combined effects of malaxation time (t) and
aqueous citric acid solution (CA) added at the beginning of the malaxation step on total polyphenols
(TP) and o-diphenols (OD) content and the antiradical power (ARP) of the olive oil extracted from the Italian
olive fruits of Coratina cultivar. Different tests were performed according to a 32 full factorial design,
varying t from 30 to 90 min and the CA from 5 to 15 ml/kgpaste. Overall optimal conditions identified by a
numerical optimisation for the three responses were found to be at t = 30 min and CA = 13.79 ml/kgpaste
under which the model predicted TP = 604.52 lgCAE/goil, OD = 80.44 lgCAE/goil and ARP = 28.73
lgDPPH/llextract. There were also linear correlations between TP (R2 = 0.8176) and OD (R2 = 0.8633) values
of olive oil and waste water. The results of this study demonstrate that considerably short malaxation
time and relatively small amounts of citric acid were required to enhance the quality of olive oil. The outcome
of our study will therefore be of great value for the commercial production of olive oil with high
level of polyphenols and o-diphenols
Detoxification of hemicellulose acid-hydrolyzates for xylitol production by yeasts
No full textCandida guilliermondii, Debaryomyces hansenii and Pachysolen tannophilus were evaluated to ferment xylose solutions prepared from hardwood hemicellulose hydrolyzates
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