Giuseppe Mascolo

Novel Sulfonolipid in the Extremely Halophilic Bacterium Salinibacter ruber

ABSTRACT Salinibacter ruber is an extremely halophilic bacterium, phylogenetically affiliated with the Flavobacterium/Cytophaga branch of the domain Bacteria. Electrospray mass analyses (negative ion) of the total lipid extract of a pure culture of S. ruber shows a characteristic peak at m/z 660 as the most prominent peak in the high-mass range of the spectrum. A novel sulfonolipid, giving rise to the molecular ion [M-H]− of m/z 660, has been identified. The sulfonolipid isolated and purified by thin-layer chromatography was shown by chemical degradation, mass spectrometry, infrared spectroscopy, and nuclear magnetic resonance analysis to have the structure 2-carboxy-2-amino-3-O-(13′-methyltetradecanoyl)-4-hydroxy-18-methylnonadec-5-ene-1-sulfonic acid. This lipid represents about 10% of total cellular lipids, and it appears to be a structural variant of the sulfonolipids found as main components of the cell envelope of gliding bacteria of the genus Cytophaga and closely related genera (W. Godchaux and E. R. Leadbetter, J. Bacteriol. 153:1238-1246, 1983) and of diatoms (R. Anderson, M. Kates, and B. E. Volcani, Biochim. Biophys. Acta 528:89-106, 1978). Since this sulfonolipid has never been observed in any other extreme halophilic microorganism, we consider the peak at m/z 660 the lipid signature of Salinibacter. This study suggests that this novel sulfonolipid may be used as a chemotaxonomic marker for the detection of Salinibacter within the halophilic microbial community in saltern crystallizer ponds and other hypersaline environments.

The role of 3-dimethylaminopropylamine and amidoamine in contact allergy to cocamidopropylbetaine

Since it has been found that all subjects with contact allergy to cocamidopropylbetaine (CAPB) have positive reactions to 3‐dimethylaminopropylamine (DMAPA), and reports have appeared in literature of the sensitizing action of amidoamine in products containing CAPB, we aimed to verify the possibility that pure amidoamine may have a sensitizing role in subjects with positive reactions to CAPB. To this end, in 10 patients with contact allergy to a commercial CAPB, we tested DMAPA 1% aq. and a pure amidoamine in concentrations ranging from 0·5% aq. to 0·1% aq. The study showed that all patients with positive reactions to DMAPA reacted to amidoamine at 0·5% and 0·25% aq., while 4 of the 10 also had positive reactions to amidoamine at 0·1% aq. We consider that simultaneous allergic reaction to DMAPA and amidoamine represents cross‐reactivity and hypothesize that DMAPA is in fact the true sensitizing substance, while amidoamine, which may in any case release DMAPA in vivo as a result of enzymatic hydrolysis, may favour the transepidermal penetration of the sensitizing agent. In addition, we advise that testing of CAPB be suspended, because, as suggested by chemico‐structural analyses and demonstrated in vivo, when thoroughly purified, it no longer has a sensitizing action.

Peroxymonosulfate-Co(II) oxidation system for the removal of the non-ionic surfactant Brij 35 from aqueous solution.

The non-ionic surfactant Brij 35 was effectively removed from concentrated aqueous solution by the peroxymonosulfate/Co(II) system, using oxone (2KHSO(5)·KHSO(4)·K(2)SO(4)) as a source of peroxymonosulfate. At pH=2.3 and initial Brij 35 concentration in the range 680-2410 mg L(-1), 86-94% removal was achieved after 24 h, using Co(II)=15 μM and oxone=5.9 mM. The effectiveness of removal did not change when initial pH was in the range 2.3-8.2. After five subsequent additions of Co(II) and oxone to the solution, COD and TOC removals increased up to 64% and 33%, respectively. Radical quenching tests confirmed that sulfate radical was the dominant radical species in the system. The main identified by-products from surfactant degradation were: (a) low molecular weight organic acids; (b) aldehydes and formates with shorter ethoxy chain than Brij 35; (c) alcohol ethoxylates carrying hydroxyl groups bonded to ethoxy chain. By-products identification allowed to hypothesize the pathways of Brij 35 degradation.

Degradation of sulphur containing s-triazines during water chlorination

Abstract The reactions of four sulphur containing s-triazines (prometryne, terbutryne, ametryne and desmetryne) with hypochlorous acid (HClO) and chlorine dioxide (ClO 2 ) have been investigated using an 11 ppm/3 ppm oxidant/herbicide ratio. The main objective of the study was the identification of by-products. Additionally, to study the effect of oxidant concentration on the reaction rate, two more oxidant/herbicide ratios (3 ppm/3 ppb and 11 ppb/3 ppb) have been investigated only for prometryne. Oxidation reactions were monitored by high performance liquid chromatography (HPLC), while, the identification of by-products was initially carried out by low resolution HPLC-mass spectrometry (HPLC-MS) and confirmed by accurate mass measurement. Under the experimental conditions ( T = 20°C, pH = 8, reaction time = 48 h), the results indicate that all the investigated triazines react in the same way with each oxidant. The reactions with HClO occur much faster than those with ClO 2 and give rise to three identified oxidation by-products: the sulfoxide, the sulfone and the sulfones hydrolysis product. The reactions with ClO 2 , instead, give rise to a sole oxidation by-product: the sulfoxide. With both oxidants, as expected, the lower the oxidant concentration the slower the oxidation rate. Based on the obtained results, a general pathway for the oxidation of sulphur containing s-triazines is proposed.

Tracing endocrine disrupting chemicals in a coastal lagoon (Sacca di Goro, Italy): sediment contamination and bioaccumulation in Manila clams.

The Water Framework Directive, recently amended with new priority substances (2013/39/EU), is meant to regulate the health status of European aquatic environments, including transitional waters. Despite the ecological and economic importance of transitional water bodies and, in particular, of coastal lagoons, a relevant example of this type of environments, little is known about their contamination by priority substances, particularly by endocrine disrupting chemicals (EDCs). In this study, a wide array of priority substances, all with recognised disrupting properties, was investigated in the Sacca di Goro Lagoon (Adriatic Sea, Italy), which receives freshwater from the Po River after draining the most urbanised and industrialised Italian regions. Flame retardants, alkylphenols, bisphenol A, natural and synthetic steroids, personal care products and legacy pollutants were investigated both in sediments and in the clam Ruditapes philippinarum collected from three sites in the lagoon. Sediments showed that most of the chemicals analysed could reach the lagoon ecosystem but their concentrations were below existing quality guidelines. Clams essentially reflected this condition although some concern was raised by polybrominated diphenyl ethers (PBDEs): the limit for the sum of six congeners set for biota in the European Directive (2013/39/EU) to protect human health was exceeded 4-5 times. No significant biota-sediment accumulation factors (BSAFs) were calculated. Nonylphenol, tonalide, PBDE, polychlorinated biphenyls and bisphenol A were the most abundant chemicals in clam tissues.

Lipids of the ultra-thin square halophilic archaeon Haloquadratum walsbyi

The lipid composition of the extremely halophilic archaeon Haloquadratum walsbyi was investigated by thin-layer chromatography and electrospray ionization-mass spectrometry. The analysis of neutral lipids showed the presence of vitamin MK-8, squalene, carotene, bacterioruberin and several retinal isomers. The major polar lipids were phosphatidylglycerophosphate methyl ester, phosphatidylglycerosulfate, phosphatidylglycerol and sulfated diglycosyl diether lipid. Among cardiolipins, the tetra-phytanyl or dimeric phospholipids, only traces of bisphosphatidylglycerol were detected. When the cells were exposed to hypotonic medium, no changes in the membrane lipid composition occurred. Distinguishing it from other extreme halophiles of the Halobacteriaceae family, the osmotic stress did not induce the neo-synthesis of cardiolipins in H. walsbyi. The difference may depend on the three-laminar structure of the cell wall, which differs significantly from that of other Haloarchaea.

OXIDATION OF NONIONIC SURFACTANTS BY FENTON AND H2O2/UV PROCESSES

Abstract The oxidation of 10 nonionic surfactants (6 alcohol ethoxylates and 4 alkylphenol ethoxylates) by Fenton and H2O2/UV processes was investigated in synthetic (deionized water) and real aqueous matrices, i.e. secondary effluent from municipal wastewater treatment plant and groundwater. Batch tests were carried out to assess the optimal dosages of reagents leading to the total removal of surfactants. Regardless to the specific surfactant, both Fenton and H2O2/UV treatments of synthetic solutions containing one single surfactant (C0=14 mg l−1) always caused its rapid and quantitative removal (96–99%) with a corresponding very low (0–18%) TOC decrease. Only for the Fenton treatment, linear relationships were found between the amounts of H2O2 and Fe2+ necessary for surfactant removal and the ethoxy chain length of each surfactant. Conversely, in the case of H2O2/UV treatment the H2O2 dosage causing the quantitative oxidation of the treated surfactant depended on the length of both chains: the ethoxy and the hydrophobic one. Mixtures of the 10 surfactants (1.4 mg l−1 each) were treated in both synthetic and real matrices. These latter were different in the case of Fenton (i.e. municipal secondary effluent) or H2O2/UV (i.e. real groundwater) treatments. Fenton treatment of municipal secondary effluent containing the surfactants mixture led to its total removal when a molar ratio [Total surfactants]/[H2O2]/[Fe2+] equal to 1/17/12 was used. As for H2O2/UV treatment of real groundwater samples, quantitative removal of surfactants mixture was achieved with a molar ratio [Total surfactants]/ [H2O2] equal to 1/7.4. Surfactants mixture removals, if compared in deionized water and in real matrices, showed the same matrix effect during both treatments, i.e. less amounts of reagents were always required in synthetic solutions.

Degradation of chlorobenzene by Fenton-like processes using zero-valent iron in the presence of Fe3+ and Cu2+.

Batch and column tests were conducted to compare the efficiencies of three Fenton‐like systems in the degradation of chlorobenzene. In the investigated systems, iron powder was the source of Fe2+ ions, and either Fe3+ or Cu2+ were added in order to enhance the degradation process. Optimum pH and concentrations of Fe3+, Cu2+ and hydrogen peroxide were assessed by treating synthetic chlorobenzene solutions both in batch and in column mode, thus achieving the minimum residual concentration of chlorobenzene. Optimum conditions assessed by means of column tests were then applied to column treatment of real chlorobenzene‐contaminated groundwater. Results showed that, when the TOC content of water was above 12 mg L−1, the performance of the Fe0/H2O2 system was enhanced by the addition of Fe3+, leading to 10–20 µg L−1 of residual chlorobenzene.

By-products Formation during the Ozonation of the Reactive Dye Uniblu-A

Abstract The degradation by ozone of the hydrolyzed Uniblu-A (Uniblu-OH), i.e. the compound found in the spent bath resulting from dyeing process with the reactive dye Uniblu-A, has been studied with the aim of identifying intermediate as well as end by-products formed. The experimental results, obtained by ozonating (16 mg O3/L in the feed gas at 100 mL/min) aqueous solutions (500 ml) of Uniblu-OH (40 mg/L), in the presence or not of t-butanol, show that the oxy-dye is completely removed within 30 minutes and that its decay results only slightly affected by the presence of t-butanol. Several organic by-products have been identified by liquid chromatography-mass spectrometry (turboionspray interface) as a result of the oxy-dye degradation. Such by-products result from oxidation of the amino group, hydroxylation of the aromatic rings, cleavage of the alkyl chain, cleavage of the sulfoalkylbenzene group leaving substituted anthraquinone structures and cleavage of the latter structures leading to phthalic acid. Such by-products are further degraded leading to the formation of low molecular weight aldehydes and acids, nitrate and sulphate. As for the formation of inorganic end by-products, after 120 minutes of ozonation, the percentages of nitrate and sulphate conversion resulted 6 and 7 %, 53 and 89% in the absence and in the presence of t-butanol respectively.

Simultaneous Cr(VI) reduction and non-ionic surfactant oxidation by peroxymonosulphate and iron powder

Some industrial wastewaters contain both hexavalent chromium and surfactants. In this work, their removal from aqueous solution by zero-valent iron (ZVI) and peroxymonosulphate (PMS) was studied using Brij 35 as a representative non-ionic surfactant. The performance of the ZVI/PMS system in the simultaneous removal of both pollutants was compared to that achieved with control solutions containing either Cr(VI) or Brij 35 separately. Reactions were carried out over 24h at initial pH=2.3 with variable initial amounts of Cr(VI) and Brij 35. The results showed that surfactant removal was enhanced in the system also containing Cr(VI). Surfactant degradation followed zero-order kinetics and produced formic acid as the main by-product, together with hydroxylated aldehydes, formates and alcohols that were identified by LC/MS. The presence of surfactant similarly enhanced Cr(VI) reduction, which also followed zero-order kinetics. Chromium removal was quantitative only when the initial chromium concentration was lower than 140 mg L(-1). Reduced chromium was mainly in the solution phase together with dissolved iron. Precipitation with NaOH was therefore required to definitively remove dissolved metals from the investigated system.