Preliminary evaluation of biopolymers production by mixed microbial culture from citrus wastewater in a MBR system using respirometric techniques

This preliminary study was aimed at evaluating the feasibility to produce biopolymers (BP) from citrus wastewater by mixed microbial culture in an anaerobic/aerobic membrane bioreactor (A/O-MBR). The activated sludge of the A/O-MBR was successfully enriched in microorganisms having a good capacity in producing intracellular biopolymers. The production of BP was found to be about 0.55 mgCOD mgCOD−1 using pure acetate at a concentration of 1000 mgCOD L−1. When using fermented wastewater, the conversion of acetate into BP product was 0.56 mgCOD mgCOD−1 in the test performed with C/N equal to 1000:1, whereas it was only 0.12 mgCOD mgCOD−1 in the test with C/N of 100:5. The results achieved suggested the feasibility to use citrus wastewater as a feedstock for biopolymers production although the low biomass storage capacity (0.26 mgCOD mgCODbiomass−1) suggested the need for optimizing the operating conditions in future studies

Chemical speciation of organic matter in natural waters. Interaction of nucleotide 5' mono-, di- and triphosphates with major components of seawater

AbstractThe interactions of nucleotide 5' mono-, di- and triphosphates in a multicomponent ionic medium simulating the macro-composition of seawater (Na+, K+, Ca2+, Mg2+, Cl-, SO42-, Synthetic Sea Water, SSW) have been investigated at different ionic strengths and at T= 25°C. A chemical speciation model, according to which all the internal interactions between the components of the ionic medium are taken into account, was applied to determine the effective formation constants of species in the nucleotide-seawater system. The results were compared to protonation parameters calculated from single electrolyte systems. A simpler model (SSW considered as a single salt BA, with Bz+ and Az-), representative of the cation (Na+, K+, Ca2+, Mg2+) and anion (Cl-, SO42-) macro-components of seawater respectively, was also used to calculate the overall complexing ability of the seawater salt towards all the systems here investigated

Bio-plastic recognition by mussels hemocytes

The growing use of bio-polymers derivatives poses an increasingly pressing problem regarding their environmental sustainability. In particular, it should be still ascertained the claimed absence of direct and indirect influence on ecosystems and the health of living organisms, including humans. Our goal was about assessing the potential effects of poly-lactates and polyhydroxyalkanoates, the most widely used bio polymers classes with promising different applications for replacing conventional plastics on natural aquatic environments. We chose M. galloprovincialis as sentinel species since their extensive filter-feeding activity. When it is exposed to microparticles can bioaccumulate them in soft tissues and organs. In the immunobiological investigation, to highlight if bio-polymers can influence the marine ecosystems, in vitro exposure assays on bivalve mussel have been carried out, and their impacts have been explored, by evaluating the cellular response of hemocytes referred to their phagocytic and/or encapsulation activity. Preliminary evidences have shown that bioplastic particles behave in a very similar way to fossil plastic triggering the immuno-system and activating the elimination of non-self particles via cellular response. As future perspectives, although it is widely recognized that in vitro testing is an effective method for defining the effects of emerging pollutants, the in vitro test will be further deepened with in vivo experiments

Sabella spallanzanii mucus contain a galactose-binding lectin able to agglutinate bacteria. Purification and characterization

Lectins are present in almost all living organisms and are involved in several biological processes, including immune responses. In the present study, a calcium dependent galactose-binding lectin exhibiting an apparent MW of 43 kDa has been characterized and purified from the mucus of the polychaete Sabella spallanzanii by using both affinity chromatography and high-pressure liquid chromatographic methods. Its agglutinating activity towards rabbit erythrocytes was significantly modified by the addition of calcium or EDTA. The activity was optimal at temperature values comprised between 4 and 18 \ub0C, maintain a 50% of activity between 20 and 37 \ub0C, was significant deleted after exposure at 50 \ub0C, and was depleted at 90 \ub0C. The S. spallanzanii Galactose-Binding Lectin (SsGBL) was able to agglutinate bacteria and to preferentially recognize Gram-negative bacteria. The strongest agglutinating activity was observed towards Vibrio alginolyticus and Escherichia coli, by contrast mucus agglutinated in a lesser extent both Aeromonas hydrophyla and the Gram-positive Micrococcus lysodeikticus thus suggesting its involvement in host pathogen interactions

Metals distribution in the organic and inorganic fractions of soil: a case study on soils from Sicily

AbstractThe content of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn, has been determined in the organic and inorganic fraction of eight soil samples from Sicily. A modified type-Tessier sequential extraction procedure has been used to recognize metals in five different fractions categorised as follows: (a) exchangeable metals, (b) metals bound to carbonates, (c) metals bound to iron and manganese oxides, (d) metals bound to organic matter, and (e) metals in residual fraction. The mineralogical composition of soils samples was characterized by X-ray diffraction. Humic substances were extracted by means of an alkaline extraction procedure. It has been found that both the mineralogical composition and the different content of humic fraction of organic matter in the soils investigated are responsible for the observed trace metal distribution. The obtained data show that a significant amount of trace metals is bound to the organic fraction where different binding sites are present simultaneously. In particular, Pb an..

Improvement of Fresh Ovine “Tuma” Cheese Quality Characteristics by Application of Oregano Essential Oils

In the present work, oregano essential oils (OEOs) were applied to process the fresh ovine cheese "Tuma" obtained by pressed cheese technology. Cheese making trials were performed under industrial conditions using ewe's pasteurized milk and two strains of Lactococcus lactis (NT1 and NT5) as fermenting agents. Two experimental cheese products (ECP) were obtained through the addition of 100 (ECP100) and 200 (ECP200) & mu;L/L of OEO to milk, while the control cheese product (CCP) was OEO-free. Both Lc. lactis strains showed in vitro and in vivo ability to grow in the presence of OEOs and to dominate over indigenous milk lactic acid bacteria (LAB) resistant to pasteurization. In the presence of OEOs, the most abundant compound found in cheese was carvacrol, constituting more than 65% of the volatile fraction in both experimental products. The addition of OEOs did not influence ash, fat, or protein content, but it increased by 43% the antioxidant capacity of the experimental cheeses. ECP100 cheeses showed the best appreciation scores by the sensory panel. In order to investigate the ability OEOs to be used as a natural preservative, a test of artificial contamination was carried out, and the results showed a significant reduction of the main dairy pathogens in OEO-added cheeses

Speciation of organic matter in natural waters. Interaction of polyacrylates with the major cation components of seawater

The speciation of some high molecular weight polycarboxylates was studied in different ionic media. Polyacrylates here investigated (W=2.0, 5.1 and 20.0 kDa) form weak species with alkali metal cations (K=102 mol l1, t=25 jC, I=0 mol l1) and quite stable complexes with alkaline earth metal cations (K>106 mol l1, t=25 jC, I=0 mol l1). Results are reported from experiments performed in a multicomponent electrolyte solution simulating the major composition of seawater (artificial seawater). Protonation constants in this medium are expressed as a polynomial function of S1/2 (S=salinity) and the sharp lowering with respect to values obtained in non-interacting aqueous tetraalkylammonium salts can be ascribed to the formation of alkali and alkaline earth cation complexes. A simplified approach, according to which the seawater salt is considered as a single 1:1 salt, was used to describe the total interacting ability of the major components of seawater towards polyacrylates. Protonation and complex formation data are reported as a function of the degree of proton dissociation and of the molecular weight: empirical equations to take into account these functions are also give