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Multiple stage anaerobic system was found to be an effective strategy for reductive decolorization of azo dyes in the presence of sulfate. Bulk color removal (56-90%) was achieved concomitant with acidogenic activity in the 1st-stage reactor (R1), while organic matter removal (≤100%) and sulfate reduction (≤100%) occurred predominantly in the 2nd-stage reactor (R2). However, azo dye reduction mechanism and metabolic routes involved remain unclear. The involved microbial communities and conditions affecting the azo dye removal in a two-stage anaerobic digestion (AD) system were elucidated using amplicon sequencing (16S rRNA, fhs, dsrB and mcrA) and correlation analysis. Reductive decolorization was found to be co-metabolic and mainly associated with hydrogen-producing pathways. We also found evidence of the involvement of an azoreductase from Lactococcus lactis. Bacterial community in R1 was sensitive and shifted in the presence of the azo dye, while microorganisms in R2 were more protected. Higher diversity of syntrophic-acetate oxidizers, sulfate reducers and methanogens in R2 highlights the role of the 2nd-stage in organic matter and sulfate removals, and these communities might be involved in further transformations of the azo dye reduction products. The results improve our understanding on the role of different microbial communities in anaerobic treatment of azo dyes and can help in the design of better solutions for the treatment of textile effluents.

The acetylation status of histones is regulated in eukaryotes by two kinds of enzymes, histone acetyltransferases (HATs) and histone deacetylases (HDACs), which are responsible for acetylation and deacetylation of lysines residues in N-terminal tails of histone.[1] Thus acetylation, together with phosphorylation and methylation of N-terminal tail of histones, are involved in regulating fundamental processes, such as proliferation and cell death.[2-3] Sodium butyrate, which belongs together with valproic acid to the class of short chain fatty acids, was the first HDAC inhibitor (HDACI) to be identified.[1] Organotin compounds have various influences on physical function including the hormone and immune systems, embryogenesis, and development. Dibutyltin and diphenyltin, metabolites of TBT and TPT, respectively, also promoted HAT activity.[4] New triorganotin(IV) complexes of valproic acid have been synthesized and investigated by spectroscopical and biological methods. An anionic, monodentate valproate ligand was observed, ester-like coordinating the tin atom on a tetra-coordinated, monomeric environment. The structures, though, can distort towards a pentacoordination, as a consequence of a long range O-Sn interaction. Crystallographic and NMR findings confirm this situation both in solid state and solution. Biological finding evidenced a clear cytotoxic action of the complexes in hepatocellular carcinoma cell cultures: one of the complexes induced an 80% cell viability reduction after 24 h treatment in HepG2 cells. This effect was accompanied by the appearance of biochemical signs of apoptosis. In Chang liver cells, the same compound induced only modest effects, suggesting a potential use as anti-cancer drug.

Ammonium nitrogen removal from a synthetic wastewater by nitrification and denitrification processes were performed in a sequencing batch biofilm reactor containing immobilized biomass on polyurethane foam with circulation of the liquid-phase. It was analyzed the effect of four external carbon sources (ethanol, acetate, carbon synthetic medium and methanol) acting as electron donors in the denitrifying process. The experiments were conducted with intermittent aeration and operated at 30±1°C in 8-hcycles. The synthetic wastewater (100 mgCOD/L and50 mgNH4+ -N/L) was added batch-wise, while the external carbon sources were added fed-batch-wise during the periods where aeration was suspended. Ammonium nitrogen removal efficiencies obtained were 95.7, 94.3 and 97.5% for ethanol, acetate and carbon synthetic medium, respectively. As to nitrite, nitrate and ammonium nitrogen effluent concentrations, the results obtained were, respectively: 0.1, 5.7 and 1.4 mg/L for ethanol; 0.2, 4.1 and 1.8 mg/L for acetate and 0.2, 6.7 and 0.8 for carbon synthetic medium. On the other hand using methanol, even at low concentrations (50% of the stoichiometric value calculated for completedenitrification), resulted in increasing accumulation of nitrate and ammonium nitrogen in the effluent over time.

Lately, the interest in nanotubes has been extended to several non-carbonaceous compounds, including conducting, semiconducting and isolating materials that find potential application in materials science, catalysis, electronics, or drug delivery. Geoinspired synthetic chrysotile (Mg3Si2O5(OH)4) is a stoichiometric silicate having a tubular nanostructure phase, and it can be blended to other compounds to yield advanced materials, without the drawbacks for human health typical of the natural chrysotile’s toxicity.1 We tried to use this as a nanostructured inorganic matrix to organize functional chromophores, such as porphyrins and their derivatives,2 and to obtain organic/inorganic hybrids having potential applications in photonics, non-linear optics and as sensors.3 The adsorption of various derivatives of the negatively charged tetra-(4-sulfonatophenyl)porphyrin (TPPS) on chrysotile has been easily achieved taking advantage of the nanotubes being positively charged over a broad range of pH, as determined via Z-potential measurements. These hybrid nanocomposites have been prepared by dropwise addition of concentrated (650 μM) aqueous solutions of the different dyes to the nanotubes aqueous suspensions. If the experiments are carried out at a neutral pH, the TPPS free base spontaneously adsorbs onto the initially white solid until charges neutralization has occurred (∼ 10 nmol TPPS /mg chrysotile). TPPS metalloderivatives (CuII, ZnII, MnIII) have been also adsorbed successfully on the inorganic matrix, allowing to prepare materials having a variety of optical properties, which have been thoroughly characterized by the combined use of UV/Vis extinction, fluorescence and resonance light scattering (RLS) techniques. TPPS/chrysotile hybrids have shown a reversible response to the presence of acids vapors or solutions, with the formation of TPPS J-aggregates after a substantial rearrangement of the dye molecules at the surface, thus pointing to possible sensor applications. The ionic self assembly approach has been also used to prepare stable colloidal dispersions of the nanotubes in chlorinated solvents through addition of an anionic surfactant (SDS), that can then interact with the tetrabutylammonium salt of TPPS, leading to supported H- and J-aggregates. The latter ones possess very narrow extinction and RLS features which are very similar to those normally observed for unsupported TPPS aggregates in water, and that seem promising for NLO applications.4